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Traditional pastures in temperate regions face limitations such as reduced growth and nutritional quality during the summer season. Plantain (P. lanceolata L.) offers advantages like increased yield and decreased nitrogen losses from grazing ruminants. Effective grazing management is essential for pasture health, and defoliation frequency and intensity play a pivotal role. This study aimed to evaluate plantain's regrowth, yield, and morpho-physiological and chemical responses under different defoliation frequencies and intensities, with the goal of enhancing its management in pastures. The study was conducted in pots within a controlled-environment growth chamber, examining the impact of three defoliation frequencies (based on extended leaf length: 15, 25 and 35 cm) and two defoliation intensities (5 and 8 cm of residual heights) with four replicates (24 pots as experimental units). The variables of interest were morphological characteristics, dry matter (DM) accumulation, herbage chemical composition, growth rate traits, and photosynthetic parameters. Defoliation frequency affected plantain's growth and nutritional composition. More frequent cuts (15 cm) resulted in lower DM yield per cut and lower stem content, while less frequent cuts (35 cm) produced higher values. Defoliation intensity influenced the proportion of leaves and stems in the total DM, with 5 cm cuts favoring leaves. Nutrient content was also affected by defoliation frequency, with less frequent cuts (35 cm) showing lower crude protein concentration and metabolizable energy content but higher neutral detergent fiber and water-soluble carbohydrate concentration. Plantain's growth rate variables were mainly influenced by defoliation frequency, with less frequent cuts promoting faster leaf appearance and growth of new leaves. The basal fluorescence variables and chlorophyll content were affected by cutting frequency, being highest when cut less frequently (35 cm), while no differences were found in the actual quantum efficiency among different defoliation frequencies and intensities. The fraction of light dedicated to non-photochemical quenching was highest when cut less frequently and more intensively. Overall, defoliation at 25 cm of extended leaf length balanced plantain forage quality and regrowth capacity. [ABSTRACT FROM AUTHOR]

An extensive discoloration (yellowing, browning), and defoliation (leaf loss) were observed in Slovak forests during the summer of 2022. These phenomena are attributed to the combination of very low atmospheric precipitation and extremely high air temperatures from June to early August. In this study, the deterioration of forest health was analysed by comparing the image classification of Sentinel-2 satellite data from the year of intense drought occur-rence, 2022, with that from a referenced year without drought occurrence, 2020. The results indicated that in 2022, the proportion of heavily damaged stands with defoliation exceeding 50% doubled, reaching 19.3% (417,000 ha), and an area of 223,000 ha experienced an increase in defoliation by 30% or more. The damage exhibited an uneven spatial distribution, with the most significant impact observed in the western and southern parts of central Slovakia, as well as partially in the southern part of eastern Slovakia. Further GIS analyses revealed that forests growing on slopes with southern aspects suffered more severe damage than with northern exposures. However, the difference between the most damaged forests with south-southeast exposure (12.2%) and the least damaged ones with north-northwest exposure (8.2%) was only 4%. The level of damage gradually decreased with increasing altitude. Nevertheless, compared to previous studies, the damage was significantly manifested even in the fourth forest vegetation zone, up to an elevation of approximately 800 m. Regarding soil texture, which influences the water regime, the damage gradually decreased with decreasing sand content, ranging from sandy soils (17.5%) to clayey soils (6.6%). [ABSTRACT FROM AUTHOR]

Denphal-type Dendrobium is the famous cut and potted flower in the world, and most cultivated in tropical and subtropical regions. However, it often suffers from cold in winter in subtropical regions. To verify the physiological response of Denphal-type Dendrobium under low temperature in this study, the mature and young plantlets of Dendrobium Udomsri Beauty were treated under 15, 10, and 5 °C, respectively. And then the electrical conductivity (EC), soluble protein, soluble sugar, free proline, malondialdehyde (MDA), chlorophyll content, and the rate of defoliation after regrowth were measured. The results showed that both mature plant and young seedlings of Dendrobium Udomsri Beauty, the EC, soluble protein, soluble sugar, free proline, MDA content, and defoliation rate were increased with the decrease of treatment temperature and the extension of treatment times. The content of chlorophyll decreased gradually with the decrease of treatment temperature and the extension of treatment times. The correlation analysis showed that soluble sugar, free proline, MDA, chlorophyll content, and defoliation rate were significantly correlated with the semi-lethal temperature. It is indicated that the content of free proline, MDA, chlorophyll, and defoliation rate could be used as the effective indexes for the comprehensive assessment of cold tolerance of Dendrobium Udomsri Beauty. [ABSTRACT FROM AUTHOR]

Ungulate herbivores shape grassland plant communities at multiple scales, ultimately affecting ecosystem function. However, ungulates have complex effects on grasslands, including defoliation, trampling, excreta return and their interactions. Moreover, the effects of ungulate density on grasslands are regulated by these three mechanisms. Nevertheless, how these three mechanisms affect biodiversity at multiple scales and community assembly remains poorly understood.Here, we conducted a 4‐year novel field experiment to disentangle the effects of defoliation, trampling, and excreta return by ungulates on plant community assembly in a temperate grassland in Inner Mongolia, China. This experiment set two different scenarios: moderate ungulate density (Moderate, characterised by selective defoliation and moderate trampling) and high ungulate density (Intense, characterised by non‐selective defoliation and heavy trampling), including different combinations of defoliation, trampling and excreta return in each scenario.We found that defoliation and trampling increased stochasticity in community assembly and promoted alpha and beta diversity under both scenarios. Specifically, defoliation promoted the coexistence of species with multiple resource acquisition strategies (higher functional trait diversity) by reducing interspecific competition; trampling tended to facilitate random species colonisation. Conversely, excreta return favoured grasses, promoting deterministic assembly and impacting species coexistence. Notably, selective defoliation in the Moderate scenario led to a dominance of stochastic processes during community assembly, whereas non‐selective defoliation still did not change the dominance of deterministic processes. Further, communities subject to selective defoliation were insensitive to changes in soil properties caused by trampling and excreta return, maintaining a high‐level beta diversity and the stochastic of community assembly.Synthesis: Our study provides important insights into the mechanisms by which ungulate herbivores influence plant community assembly, suggesting that defoliation and trampling have the potential to drive stochastic processes, while excreta return plays the opposite role. Our study also suggests that selective foraging by ungulates acts as stronger stochastic forces during community assembly compared to non‐selective defoliation. These results imply that considering ungulate feeding preferences and foraging behaviour in grassland management will help prevent biodiversity loss and biotic homogenisation. [ABSTRACT FROM AUTHOR]

Cat's claw creeper (Dolichandra unguis‐cati), native to tropical South America, is a major invasive species and a target for biological control in Australia, South Africa and some South Pacific Island countries. Native range surveys in Argentina, Brazil, Paraguay and Venezuela have identified eight insects and four fungal pathogens as potential agents. Five leaf‐feeding insects a tortoise beetle Charidotis auroguttata, two tingids Carvalhotingis visenda and C. hollandi, a leaf‐tying moth Hypocosmia pyrochroma and a leaf‐mining beetle Hedwigiella jureceki, have been tested and all were released in South Africa. Four of these have become established but are not widespread and cause only limited damage. In Australia, only three of these, C. visenda, H. pyrochroma and H. jureceki were released, while C. auroguttata was not approved due to perceived non‐target risks. All agents have become widely established, except for H. pyrochroma which is restricted to riparian corridors in southeast Queensland. In South Africa, an accidentally introduced leaf‐spot pathogen, Neoramulariopsis unguis‐cati, causes necrotic lesions and premature abscission of leaves in cat's claw creeper infestations, resulting in widespread defoliation. Based on its impact and field‐host specificity in its native range and in South Africa, the pathogen has been prioritised for evaluation as a potential additional agent in Australia. The current priority is to seek approval for the introduction of this leaf‐spot pathogen into Australia. Future research should focus on the gall‐inducing rust Uropyxis rickiana and the seed‐feeding weevil Apteromechus notatus as prospective agents. [ABSTRACT FROM AUTHOR]

Hymenoscyphus fraxineus causes ash dieback in Europe. It overwinters on ash leaf residue (rachis) within the forest litter. In late spring, the fungus produces apothecia on the rachises and releases ascospores to infect leaves. Previous studies reported that H. fraxineus was able to produce apothecia on the rachis for 5 years after the leaf infection under artificial conditions. However, ash litter is known to decompose rapidly in situ. We therefore monitored the decomposition kinetics of ash leaf debris and the persistence of the pathogen, as well as its ability to produce apothecia in the forest litter. For this, leaves shed in autumn in stands affected by ash dieback were placed in mesh bags and left in the forest litter for 6, 18 and 30 months. At each sampling period, litter mass loss and level of colonization of the rachises by H. fraxineus were measured, as was the pathogen's ability to produce apothecia on them. Despite high fragmentation, about 14% of the rachis dry weight remained in the mesh bags after 30 months, and the pathogen retained the ability to produce apothecia on these rachises. A simulation estimating the age composition of the colonized rachises present in the litter during the fruiting period was developed from these results. It shows that the persistence of H. fraxineus in old rachises of the litter represents a reservoir of inoculum that could compensate for poor colonization of autumn leaves and revive local outbreaks after years of unfavourable weather for the development of the pathogen. [ABSTRACT FROM AUTHOR]

The Ore Mountains were historically one of the most polluted areas in Europe, where high sulphur dioxide concentrations and a high level of atmospheric deposition led to a vast decline in Norway spruce stands in the mountain ridge plateau. In this article, we evaluate the trends in the atmospheric deposition load, soil chemistry, tree nutrition, crown defoliation and height increment in a network of twenty research plots monitored for last thirty years in this region. The decrease in sulphur and nitrogen deposition was most pronounced at the end of 1990s. Extreme values of sulphur deposition (100–200 kg.ha−1.year−1) were recorded in throughfall under mature Norway spruce stands in the late 1970s, and after felling of the damaged stand, the deposition levels were comparable to open plot bulk deposition. Nitrogen deposition decreased more slowly compared with sulphur, and a decrease in base cation deposition was observed concurrently. The current deposition load is low and fully comparable to other mountain areas in central Europe. Accordingly, the health of young spruce stands, as assessed by defoliation and height increment, has improved and now corresponds to the Czech national average. On the other hand, no significant changes were observed in the soil chemistry, even though some of the plots were limed. Acidic or strongly acidic soil prevails, often with a deficiency of exchangeable calcium and magnesium in the mineral topsoil, as well as decreases in available phosphorus. This is reflected in the foliage chemistry, where we see an imbalance between a relatively high content of nitrogen and decreasing contents of phosphorus, potassium and calcium. Despite the observed positive trends in air quality and forest health, the nutritional imbalance on acidified soils poses a risk for the future of forest stands in the region. [ABSTRACT FROM AUTHOR]

Shoot branches grow from axillary buds and play a crucial role in shaping shoot architecture and determining crop yield. Shade signals inactivate phytochrome B (phyB) and induce bud dormancy, thereby inhibiting shoot branching. Prior transcriptome profiling of axillary bud dormancy in a phyB‐deficient mutant (58M, phyB‐1) and bud outgrowth in wild‐type (100M, PHYB) sorghum genotypes identified differential expression of genes associated with flowering, plant hormones, and sugars, including SbCN2, SbNCED3, SbCKX1, SbACO1, SbGA2ox1, and SbCwINVs. This study examined the expression of these genes during bud dormancy induced by shade and defoliation in 100M sorghum. The aim was to elucidate the molecular mechanisms activated by shade in axillary buds by comparing them with those activated by defoliation. The expression of marker genes for sugar levels suggests shade and defoliation reduce the sugar supply to the buds and induce bud dormancy. Intriguingly, both shade signals and defoliation downregulated SbNCED3, suggesting that ABA might not play a role in promoting axillary bud dormancy in sorghum. Whereas the cytokinin (CK) degrading gene SbCKX1 was upregulated solely by shade signals in the buds, the CK inducible genes SbCGA1 and SbCwINVs were downregulated during both shade‐ and defoliation‐induced bud dormancy. This indicates a decrease in CK levels in the dormant buds. Shade signals dramatically upregulated SbCN2, an ortholog of the Arabidopsis TFL1 known for inhibiting flowering, whereas defoliation did not increase SbCN2 expression in the buds. Removing shade temporarily downregulated SbCN2 in dormant buds, further indicating its expression is not always correlated with bud dormancy. Because shade signals also trigger a systemic early flowering signal, SbCN2 might be activated to protect the buds from transitioning to flowering before growing into branches. In conclusion, this study demonstrates that shade signals activate two distinct molecular mechanisms in sorghum buds: one induces dormancy by reducing CK and sugars, whereas the other inhibits flowering by activating SbCN2. Given the agricultural significance of TFL1‐like genes, the rapid regulation of SbCN2 by light signals in axillary buds revealed in this study warrants further investigation to explore its potential in crop improvement strategies. [ABSTRACT FROM AUTHOR]

Severe infection of stem rot was observed on plants of Withania somnifera during January and February of 2020 and 2021. Initial symptoms appeared on the plants showing paleness at infected areas, cottony, fluffy white mycelia was observed on the leaves, stem and inflorescence. In advanced stage of infection wilting of stem and defoliation was observed leading to partial or whole plant death. Based on its morphological and molecular traits, the fungus was identified as Sclerotinia sclerotiorum. Pathogenicity test was performed under controlled conditions resulting in similar symptoms to those observed in field. To the best of our knowledge, this is the worldwide first evidence of S. sclerotiorum causing stem rot disease on W. somnifera. [ABSTRACT FROM AUTHOR]

The tussock moth, Orgyia trigotephras Boisduval (Lepidoptera: Erebidae), is one of the main emerging pests of kermes oak, Quercus coccifera L. (Fagaceae), in the Mediterranean area, where it can cause the defoliation of several hectares of forests during its population outbreaks. Despite this, no specific sampling procedures to properly estimate the population density of this pest have been developed yet. The aims of this research were to develop and compare enumerative and binomial sequential sampling plans to estimate the population density of O. trigotephras in forest environments. Data were collected in four forest stands dominated by Q. coccifera in Tunisia for 7 years (from 2013 to 2019) to take into consideration the potential spatio‐temporal variability in pest density. Plant community composition was determined at the beginning of the experimental trials, and enumerative and binomial sampling plans were developed at precision levels of 0.15 and 0.25. Over the entire sampling period, the average O. trigotephras egg batch density differed significantly among sites. Sample sizes of enumerative sampling plans were approximately 39 and 109 trees to estimate an average density of 0.50 O. trigotephras egg batches per tree at the precision levels of 0.25 and 0.15, respectively. Instead, binomial sequential sampling plans required smaller sampling sizes than the enumerative sampling plan. Our findings represent the baseline to develop a program for monitoring O. trigotephras at a large spatial scale. [ABSTRACT FROM AUTHOR]

Teratosphaeria nubilosa is the predominant causal agent of Teratosphaeria leaf disease (TLD) in experimental plantations of E. globulus in Brazil. It exhibits slow vegetative growth and lack of sporulation in in vitro culture, making it difficult to obtain enough ascospores for mass inoculation. This study aimed to establish an inoculation method based on ascospore ejection from naturally infected leaves and use it to assess the response to T. nubilosa of eucalypt species and interspecific hybrids. First, the optimal temperature and incubation time for ascospores ejection from naturally infected E. globulus leaves were determined in vitro. Then, these optimal conditions were used to assess the response of eight eucalypt genotypes to T. nubilosa inoculation using ejected ascospores. The infected leaves were placed above (T1), above and under (T2) or under (T3) the plants to be inoculated. Significant differences in disease incidence, disease severity and plant defoliation were observed among genotypes and inoculation treatments. Plants exhibited higher incidence, more severe symptoms and more defoliation when exposed to T2. E. globulus and E. globulus × E. nitens clones were the most susceptible whereas an E. benthamii clone was immune. The sources of resistance identified in this work can be used in hybridization programmes with E. globulus to obtain interspecific hybrids expressing resistance to T. nubilosa and retaining the desirable traits for planting in temperate climates. The inoculation method optimized in this work could be used for small and medium‐scale screening of Eucalyptus spp. resistant to TLD. However, periodic validation of the species and genotype of the fungus associated with the naturally infected leaves used for inoculation and confirmation of the resistant phenotype of the selected eucalypt clones or progenies through experimental replications over time must be conducted. [ABSTRACT FROM AUTHOR]

Aims: We aimed to identify the optimal combination of selenium (from Na2SeO4) and secondary elements required for obtaining the best nutritive characteristics and quality of 'Qingcui' plums. Methods: Five treatments (Na2SeO4 with MgSO4 and CaSO4) and a control treatment without Se, Mg, Ca, or S were applied to 2-year-old 'Qingcui' plum trees in a greenhouse. Plum leaves and fruit were analyzed for color, nutrient, and quality characteristics during the growing and deciduous seasons as well as the following year. Results: Leaf color parameters, pigment content, and specific weight significantly improved by CaSO4 addition during the growing and deciduous seasons. Ca and Mg contents during the growth, defoliation, and young leaf stages of the following year exhibited consistent trends under the different treatments, whereas Se and S contents differed according to the season and treatment. Thus, Mg and S showed high mobility and reutilization rates, whereas Ca and S showed poor mobility and reutilization rates. Leaf and fruit nutrient contents decreased in the order of Ca > Mg > S and S > Ca > Mg, respectively. The combination of 77 mg Na2SeO4, 10 g MgSO4, and 19 g CaSO4 yielded optimal fruit quality in terms of fruit weight, hardness, and soluble solids and fruit Se content. A large amount of Ca was present in the cell wall, whereas S and Mg were mainly observed as soluble components. Conclusions: Our study revealed the best combination of Se and secondary elements leading to optimal leaf nutrition and fruit Se content and quality in 'Qingcui' plums. [ABSTRACT FROM AUTHOR]

Plants employ various strategies to mitigate the impact of herbivory and one such strategy involves the associations with fungal endophytes. Some cool‐season forage grasses benefit from protection against herbivores by Epichloë fungal endophytes. However, since the maintenance of symbiosis relies on the plant, costs of hosting endophytes have been also observed. This becomes particularly crucial when forage varieties, inoculated with endophytes that are nontoxic to livestock but still protect host against insect herbivores, experience significant foliage loss (defoliation). We investigated the impact of a nontoxic Epichloë endophyte on the responses of tall fescue plants to defoliation across two morphotype varieties, Continental and Mediterranean, and different seasonal contexts. Under specific defoliation treatments, endophyte‐symbiotic plants showed reduced postdefoliation recovery, indicating the costs of hosting the endophyte for host plants. However, these conditions were not the most severe for plant growth. Regardless of the endophyte's presence, plants from Continental morphotype exhibited superior recovery than those from Mediterranean morphotype, an effect that was more pronounced in summer. Notably, the endophyte promoted plant growth after defoliation in winter for both morphotypes. Our study offers insights into mitigating endophyte‐associated costs on plant recovery postdefoliation by strategically managing cutting intensity and frequency, considering the seasonal variation. [ABSTRACT FROM AUTHOR]

The rubber tree (Hevea brasiliensis) is one of the major domesticated crops planted commercially for the production of natural rubber (NR) worldwide. In recent years, rubber trees in the Southern states of India and other rubber-producing countries have experienced a severe leaf spot disease, characterized by the appearance of several brown circular spots in the initial stage, which later spread all over the lamina of fully matured leaves, leading to yellowing and defoliation. The causal organism of this Circular Leaf Spot (CLS) disease has not been conclusively identified in any previous studies. In this study, we collected infected leaf samples from various locations in the South Indian states. We aimed to identify the actual fungal pathogen that causes the CLS disease on rubber trees. Based on the morphological and molecular analysis of the most frequently isolated fungi from infected leaf samples were identified as Colletotrichum siamense and Colletotrichum fructicola. Pathogenicity tests also confirmed the involvement of isolated Colletotrichum spp. in the development of CLS disease. These findings provide valuable insights into understanding the CLS disease and its impact on rubber cultivation. To our knowledge, it is the first report of C. siamense and C. fructicola associated with CLS disease of rubber trees in India. [ABSTRACT FROM AUTHOR]

Over the course of the year, temperate trees experience extremes in temperature and day length. In order to protect themselves from frost damage in winter, they enter a dormant state with no visible growth where all leaves are shed and buds are dormant. Also the young floral tissues need to withstand harsh winter conditions, as temperature fruit trees like apple develop their flower buds in the previous year of fruit development. So far, the genetic control of induction and release of dormancy is not fully understood. However, the transcription factor family of DORMANCY-Associated MADS-box (DAM) genes plays a major role in the control of winter dormancy. One of these genes is MdDAM4. This gene is expressed in the early phase of bud dormancy, but little is known about its function. Six transgenic apple lines were produced to study the function of MdDAM4 in apple. For plant transformation, the binary plasmid vector p9oN-35s-MdDAM4 was used that contains the coding sequence of MdDAM4 driven by the 35S promoter. Transgenicity of the lines was proven by PCR and southern hybridization. Based on siRNA sequencing and phenotypic observations, it was concluded that line M2024 overexpresses MdDAM4 whereas the gene is silenced in all other lines. Phenotyping of the transgenic lines provided evidence that the overexpression of MdDAM4 leads to an earlier induction and a later release of dormancy. Silencing this gene had exactly the opposite effects and thereby led to an increased duration of the vegetation period. Expression experiments revealed genes that were either potentially repressed or activated by MdDAM4. Among the potentially suppressed genes were several homologs of the cytokinin oxidase 5 (CKX5), five LOX homologs, and several expansins, which may indicate a link between MdDAM4 and the control of leaf senescence. Among the potentially activated genes is MdDAM1, which is in line with observed expression patterns during winter dormancy. MdDAM2, which shows little expression during endodormancy also appears to be activated by MdDAM4. Overall, this study provides experimental evidence with transgenic apple trees for MdDAM4 being an important regulator of the onset of bud dormancy in apple. [ABSTRACT FROM AUTHOR]

This insight article comments on: Ziegler C, Cochard, H, Stahl C, Bastien Gérard LF, Goret J, Heuret P, Levionnois S, Maillard P, Bonal D, Coste S. 2024. Residual water losses mediate the trade-off between growth and drought survival across saplings of 12 tropical rainforest tree species with contrasting hydraulic strategies. Journal of Experimental Botany 75, 4128–4147. [ABSTRACT FROM AUTHOR]

Bougainvillea glabra is popular for its beautiful color and easy maintenance. However, there are still problems that arise especially in the rainy season, one of which is bougainvillea difficulty flowering. To support the good and fast growth of bougainvillea plants, additional defoliation and kinetin growth regulator treatments are needed. Defoliation can increase the flowering process by removing young, newly grown leaves so that photosynthate translocation can fully form flowers. Kinetin is a cytokinin hormone that plays an active role in bud formation. The purpose of this research was to study the effect of defoliation and kinetin on the growth and flowering of bougainvillea glabra. This research was conducted at the Kediri Bougainvillea Center in Dawung Bedug Village, Ngadiluwih District, Kediri Regency. This research location has an altitude of 78 meters. The method used in the research is Randomized Group Design (RGD) consisting of two factors repeated 3 times. If there are significantly different results, it will be continued with the BNJ test at the 5% level. The results of this research indicate that kinetin concentration does not provide an interaction with defoliation on plant length, leaf area, number of branches, number of flower bract and length of freshness of flowers, but provided interaction on number of leaves. The no defoliation treatment was the best treatment for number of bushes with a mean of 26.67 while giving the concentration of 25 ppm kinetin is the best treatment for length of bougainvillea flower freshness with a mean of 93.71. [ABSTRACT FROM AUTHOR]

Contextualization: forage production response is determined by factors inherent to the ecotype and external environmental and management conditions. The high variation of factors influencing forage growth implies the need to establish responses based on the biological development regarding the accumulated temperature. Knowledge gap: the growth response of Cenchrus Clandestinus expressed in heating degree days (HDDs) when fertilized with different doses of N is unknown to establish grazing times at peak biomass accumulation accurately. Purpose: to determine the growth dynamics of kikuyu grass with different levels of nitrogen fertilization. Methodology: a control treatment without application of any source of N (T0) was evaluated, a dosage of 100 kg. N ha.-1 (T1) and a dosage of 150 kg. N ha.-1 (T2). The fertilization plan was programmed for 42-day defoliation with a residual height of 10cm. Subsequently, the growth of kikuyu grass was evaluated with a seven-day frequency based on the analysis of dry matter, chlorophyll content, stomatal conductance, number of leaves, height, leaf area, and dry matter of leaves and stems. Growth rates were calculated from the dry matter of the forage: Absolute Growth Rate (AGR), Relative Growth Rate (RGR), Net Assimilation Rate (NAR), Specific Leaf Area (SLA), Leaf Area Ratio (LAR), and Leaf Area Index (LAI). Analysis of repeated measures was carried out to determine the effect per sampling point (HDDs) in a completely randomized arrangement. Results and conclusions: with the application of 150 kg. N ha.-1 (T2) and 208.6 HDDs (42 days), plants showed higher growth rate, leaf tissue production, leaf area, and greater height. [ABSTRACT FROM AUTHOR]

Positive plant–plant interactions (facilitation) may enhance the recruitment and establishment of species less adapted to local macroclimatic conditions. A major cause of this effect is climatic buffering, which implies an increased mismatch between the macroclimatic conditions and the climatic requirements of the existing community – climatic disequilibrium – of plants living under canopies. Here we explore the effect of drought‐induced defoliation of Mediterranean shrubland canopy on the recruitment of woody species. We analyzed the differences in the climatic disequilibrium across different categories of canopy defoliation and plant–plant interactions: facilitation, neutral and inhibition. Climatic disequilibrium was estimated as the Euclidean distance in the multivariate environmental space between observed macroclimate and community inferred climate. The inferred climate was calculated by averaging the coordinates of the species' climatic niche centroids, obtained from species distribution, weighted by the species' relative abundances in each community. We found that the recruiting community growing under canopy showed higher climatic disequilibrium than the community growing in the gaps. The facilitated recruiting community growing under dead and living canopy showed the highest disequilibrium, followed by the community growing under mid‐affected canopy. The climatic disequilibrium of the recruiting communities experiencing neutral and inhibited interaction was not affected by canopy defoliation. These findings indicate that the climatic disequilibrium of the recruiting community is determined by the facilitation–competition balance. Living canopy provides climatic buffering, but it also implies competition, while dead canopy may provide some structural climatic buffering, without implying competition for resources. These results highlight the relevance of incorporating plant–plant interactions, particularly facilitation, to better forecast plant community responses to extreme climate events and climate change. [ABSTRACT FROM AUTHOR]

Understanding mesocarnivore responses to both natural and anthropogenic disturbance is crucial for understanding species' potential to maintain landscape persistence into the future. We examined the response of five mesocarnivore species (bobcat, coyote, fisher, gray fox, and red fox) to both types of disturbances and climatic conditions. The Northeastern U.S. has experienced multiple large‐scale disturbances, such as a mass defoliation event following larval spongy moth outbreak and high densities of infrastructure that divide the natural landcover into roadless zones where these species inhabit. Using dynamic occupancy models in a Bayesian framework, we aimed to (1) examine variation in species' responses over a 4‐year study by estimating variation in site‐level occupancy, colonization and extirpation of each species in the state of Rhode Island relative to natural disturbance (i.e., defoliation event), anthropogenic disturbance (i.e., parceling of natural landcover bounded by roads, distance to roads), and climate (i.e., seasonal precipitation) and (2) compare current occurrence trends to predicted asymptotic occupancy to identify key variables contributing to distribution instability. Our findings indicated declines in the occurrence of both fox species, and fisher. There was variation in mesocarnivore response to disturbance among the species. We found gray fox and fisher occupancy dynamics to be sensitive to all forms of disturbance and coyote occurrence was positively associated with anthropogenic disturbance. Although bobcat and red fox were predicted to respond positively to future climate scenarios, fisher and gray fox were not, and persistence of fisher and gray fox in a landscape of disturbance relies on large areas with high forest and shrubland cover. With the wide‐spread spongy moth outbreak across much of southern New England, our findings indicate that efforts to conserve forested lands may be crucial in maintaining the persistence of several mesocarnivore species in this region experiencing large‐scale disturbance. [ABSTRACT FROM AUTHOR]

The perennity of grassland species such as Lolium perenne greatly depends on their ability to regrow after cutting or grazing. Refoliation largely relies on the mobilization of fructans in the remaining tissues and on the associated sucrose synthesis and transport towards the basal leaf meristems. However, nothing is known yet about the sucrose synthesis pathway. Sucrose Phosphate Synthase (SPS) and Sucrose Synthase (SuS) activities, together with their transcripts, were monitored during the first hours after defoliation along the leaf axis of mature leaf sheaths and elongating leaf bases (ELB) where the leaf meristems are located. In leaf sheaths, which undergo a sink‐source transition, fructan and sucrose contents declined while SPS and SuS activities increased, along with the expression of LpSPSA, LpSPSD.2, LpSuS1, LpSuS2, and LpSuS4. In ELB, which continue to act as a strong carbon sink, SPS and SuS activities increased to varying degrees while the expression of all the LpSPS and LpSuS genes decreased after defoliation. SPS and SuS both contribute to refoliation but are regulated differently depending on the source or sink status of the tissues. Together with fructan metabolism, they represent key determinants of ryegrass perennity and, more generally, of grassland sustainability. [ABSTRACT FROM AUTHOR]

The persistent increase in forest pest outbreaks requires timely detection methods to monitor the disaster precisely. However, early detection is challenging due to insufficient temporal observation and subtle tree changes. This article proposed a novel framework that collaborates multi-source remote sensing data and uses a change detection algorithm to archive early detection of infestation caused by Dendrolimus tabulaeformis Tsai et Liu (D. tabulaeformis) attacks. First, all available Sentinel-2 images with less than 20% cloud cover were utilized. During periods with long intervals (>16 days) between Sentinel-2 images, Landsat-8 images with less than 20% cloud cover were downscaled to a spatial resolution of 10 m using a deep learning algorithm to meet the requirement for a high temporal frequency of clear observations. Second, the spectral index differences between healthy and infested trees were examined to address the challenge of detecting subtle changes in pest attacks. The Enhanced Vegetation Index (EVI) was selected for early defoliation detection. On this basis, the EWMACD (Exponentially Weighted Moving Average Change Detection) algorithm, which is sensitive to subtle changes, was enhanced to improve the capability of detecting early D. tabulaeformis attacks. The assessment showed that the overall accuracy of the change detection (F1 score) reached 0.86 during the early stage and 0.88 during the late stage. The temporal accuracy (Precision) was 84.1% during the early stage. The accuracy significantly improved compared to using a single remote sensing data source. This study presents a new framework capable of monitoring early forest defoliation caused by D. tabulaeformis attacks and offering opportunities for predicting future outbreaks and implementing preventive measures. [ABSTRACT FROM AUTHOR]

Leguminous shade trees are ubiquitous parts of tea plantations of the Terai region. However, their shed leaves might have an effect on the soil microflora under those shade trees, so it is important to find out how leaf litter affect the soil microflora. Isolation of soil microbial consortia followed by downstream experiments were conducted to observe the tolerance/susceptible pattern of those soil microflora against the fallen leaves. Sample from under Albizia odoratissima has higher organic carbon, organic matter and nitrogen content but the same property was found to be low in the sample collected under Melia azedarach. Isolation of consortia was done on nutrient agar. In vitro tolerance assay was conducted to find out the tolerance pattern against leaf extracts, heavy metal salts, pesticides, antibiotics and antifungals. Heavy metals salts like Arsenic trioxide (AS2O3) and Cupric chloride (CuCl2); and pesticides like Thiamethoxam; Spiromesifen; Phorate etc. showed no inhibition against all the isolated consortia. Co-Trimoxazole and Augmentin have not showed any inhibition except consortia under Derris robusta, whereas no antifungals but Itraconazole had an impact over all the consortia. Shade trees, being a crucial member of the tea plantations, cannot be removed but replacement of these with other species could be a probable option, besides this limited use of chemical pesticides and fertilizers should be taken into consideration strictly to restrain the microbial population in tea garden soil. So, this study has disclosed the acceptability of each and every shade tree used in this region. [ABSTRACT FROM AUTHOR]

Central African evergreen broadleaved forests around the equator exhibit a double annual cycle for canopy phenology and carbon uptake seasonality. The underlying drivers of this behavior are poorly understood and the double seasonality is not captured by land surface models (LSM). In this study, we developed a new leaf phenology module into the ORCHIDEE LSM (hereafter ORCHIDEE‐AFP), which utilizes short‐wave incoming radiation (SWd) as the main driver of leaf shedding and partial rejuvenation of the canopy, to simulate the double seasonality of central African forests. The ORCHIDEE‐AFP model has been evaluated by using field data from two forest sites and satellite observations of the enhanced vegetation index (EVI), which is a proxy of young leaf area index (LAIYoung) with leafage less than 6 months, as well as six products of GPP or GPP proxies. Results demonstrate that ORCHIDEE‐AFP successfully reproduces observed leaf turnover (R = 0.45) and young leaf abundance (R = 0.74), and greatly improve the representation of the bimodal leaf phenology. The proportion of grid cells with a significant positive correlation between the seasonality of modeled LAIYoung and observed EVI increased from 0.2% in the standard model to 27% in the new model. For photosynthesis, the proportions of grid cells with significant positive correlations between modeled and observed seasonality range from 26% to 65% across the six GPP evaluation products. The improved performance of the ORCHIDEE‐AFP model in simulating leaf phenology and photosynthesis of central African forests will allow a more accurate assessment of the impacts of climate change in tropical forests. Plain Language Summary: Evergreen broadleaved forests in central Africa near the equator have a unique behavior where their leaf growth and ability to take in carbon peak twice a year. However, the reason underlying this behavior is not well understood, and the current process‐oriented terrestrial biosphere models can not represent this double peak. In this study, we integrated a new module, which uses sunlight as the main factor for when leaves fall and new ones grow in the forest, into a popular process‐oriented terrestrial biosphere model called ORCHIDEE, to simulate this unique behavior in central African forests (hereafter ORCHIDEE‐AFP). We tested our model using real‐world data from the forests acquired at the site level and satellite images. The results show that our new model can successfully simulate when leaves change and how much carbon the forests take in. The new model demonstrates better performance than the standard model. Our improved model will be useful for predicting the future of these forests more accurately under climate change. Key Points: Solar radiation is an adequate climate factor to drive the bimodal leaf phenology of central tropical African rainforestsWe developed a new phenology scheme with solar radiation‐triggered leaf shedding and flushing for the ORCHIDEE land surface model (LSM)The ORCHIDEE LSM with the new phenology scheme captures central tropical African rainforests' bimodal leaf phenology and photosynthesis [ABSTRACT FROM AUTHOR]

We compared three methods for estimating current-year spruce budworm (Choristoneura fumiferana (Clem.)) defoliation from 2014 to 2021 using a network of 99 permanent sample plots in central Gaspé Peninsula, Québec. Percent current-year defoliation was measured by assessing shoots from mid-crown branches, ocular ratings of all individual trees using binoculars, and provincial government aerial surveys. Ocular survey defoliation differed from branch sample defoliation in 5–6 out of 7 years, consistently underestimating defoliation, across the full range of defoliation severity observed. Nested mixed-effect models for fir–spruce combined, balsam fir, white spruce, and black spruce ocular survey defoliation bias resulted in marginal R2 of 0.40, 0.47, 0.82, and 0.86, respectively. Current defoliation severity and its interaction with previous year defoliation and weather conditions significantly affected ocular survey bias. Correspondence of aerial survey estimates and mean plot defoliation occurred in only 43% of all plot-years and ranged from 14%–58% in individual years. Differences between aerial survey defoliation and plot values mainly resulted from assigning an adjacent class (e.g., light <30% assigned as moderate 31%–70% defoliation) or misplaced defoliation polygon boundaries, suggesting that assignment of aerial survey defoliation to plots or specific ground areas needs ground truth sampling. [ABSTRACT FROM AUTHOR]

The aluminium smelter in Žiar nad Hronom has operated since 1953. As a result, the surrounding area is now one of the most polluted regions in Slovakia. Since the implementation of new production and filtration technologies in 1996, the amount of emissions has significantly decreased. Our aim was to evaluate the long-term restoration of an environment that has been damaged by fluorine-based air pollutants. We analysed the contamination of forest ecosystems in three beech stands at various distances from the emission source (2, 7, and 18 km). Signs of restoration in adult beech trees were observed through a decrease in defoliation and a reduction in the necrotic disease of the bark in tree crowns. However, the impacts of air pollution on ectomycorrhizal associations persist. In the reduced number of ectomycorrhizal fungal species (16 species in the polluted stand compared to 38 species in the control stand), the low representation of sensitive fungal orders (Cantharellales, Gomphales, and Boletales), and the indices of species richness and heterogeneity (Hill, Margalef, Simpson, and Shannon–Weaver). In some respects, the findings indicate that the beech ecosystem is capable of revitalization within 25 years after a reduction in air pollution. However, much more sensitive indicators of successful restoration, compared to the characteristics of the trees, are the communities of macromycetes. [ABSTRACT FROM AUTHOR]

In this study, the effects of defoliation caused by fungal pathogens on the tree vitality and growth of a 33-year old Douglas-fir (Pseudotsuga menziesii) provenance plantation in northwestern Bulgaria was presented. The results of the conducted surveys in 2011 and 2020 showed that there were significant differences between the individual provenances of Douglas-fir concerning their susceptibility to the needle cast diseases, caused by the fungal pathogens Rhabdocline pseudotsugae and Phaeucryptopus gaeumannii. The extent of damage, expressed as the amount of Douglas-fir needles cast, varied among provenance groups in individual years. A serious degree of defoliation was assessed among all continental provenances. In 2011, all examined trees from the group of continental provenances had severe symptoms of the needle cast disease. In 71.5% of them, the defoliation of the crowns was over 25% – moderately to severely affected. The average degree of defoliation varied from 18.3% (32 Wаrm Springs) to 89.3% (55 Alamogordo). In 2020, severe defoliation was found among all continental provenances. Both fungal pathogens were found as causes of the defoliation of 64.3% of the trees. The growth indicators: average height, average diameter at breast height, average height- and diameter increment for survived provenances in 2011 (at age 24) and 2020 (at age 33) were evaluated. The loss of needles and the reduced physiological function of the trees affected their vitality in the following years. Relationships between the average current annual height and diameter increment by provenance groups for 2003–2011 and 2011–2020 were calculated. It was found that with an increase in the degree of defoliation, the height and diameter increment of the provenances decreases. [ABSTRACT FROM AUTHOR]

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Leaves are important 'source' organs that synthesize organic matter, providing carbon sources for plant growth. Here, we used Populus talassica × Populus euphratica , the dominant species in ecological and timber forests, to simulate carbon limitation through artificial 25%, 50%, and 75% defoliation treatments and explore the effects on root, stem, and leaf morphology, biomass accumulation, and carbon allocation strategies. At the 60th d after treatment, under 25% defoliation treatment, the plant height, specific leaf weight, root surface area and volume, and concentrations of non-structural carbohydrates in stem and root were significantly increased by 9.13%, 20.00%, 16.60%, 31.95%, 5.12%, and 9.34%, respectively, relative to the control. There was no significant change in the growth indicators under 50% defoliation treatment, but the concentrations of non-structural carbohydrates in the leaf and stem significantly decreased, showing mostly a negative correlation between them. The opposite was observed in the root. Under 75% defoliation treatment, the plant height, ground diameter, leaf number, single leaf area, root, stem, and total biomass were significantly reduced by 14.15%, 10.24%, 14.86%, 11.31%, 11.56%, 21.87%, and 16.82%, respectively, relative to the control. The concentrations of non-structural carbohydrates in various organs were significantly reduced, particularly in the consumption of the starch concentrations in the stem and root. These results indicated that carbon allocation strategies can be adjusted to increase the concentration of non-structural carbohydrates in root and meet plant growth needs under 25% and 50% defoliation. However, 75% defoliation significantly limited the distribution of non-structural carbohydrates to roots and stems, reduced carbon storage, and thus inhibited plant growth. Defoliation-induced carbon limitation altered the carbon allocation pattern of P. talassica × P. euphratica , and the relationship between carbon reserves in roots and tree growth recovery after defoliation was greater. This study provides a theoretical basis for the comprehensive management of P. talassica × P. euphratica plantations, as well as a reference for the study of plantation carbon allocation strategies in the desert and semi-desert regions of Xinjiang under carbon-limitation conditions. [ABSTRACT FROM AUTHOR]

Forest pests pose a major threat to ecosystem services worldwide, requiring effective monitoring and management strategies. Recently, satellite remote sensing has emerged as a valuable tool to detect defoliation caused by these pests. Lymantria dispar, a major forest pest native to Japan, Siberia, and Europe, as well as introduced regions in North America, is of particular concern. In this study, we used Sentinel-2 satellite imagery to estimate the defoliation area and predict the distribution of L. dispar in Toyama Prefecture, central Japan. The primary aim was to understand the spatial distribution of L. dispar. The normalized difference vegetation index (NDVI) difference analysis estimated a defoliation area of 7.89 km2 in Toyama Prefecture for the year 2022. MaxEnt modeling, using defoliation map as occurrence data, identified the deciduous forests between approximately 35° and 50° at elevations of 400 m and 700 m as highly suitable for L. dispar. This predicted suitability was also high for larval locations but low for egg mass locations, likely due to differences in larval habitats and ovipositing sites. This study is the first attempt to utilize NDVI-based estimates as a proxy for MaxEnt. Our results showed higher prediction accuracy than a previous study based on the occurrence records including larvae, adults, and egg masses, indicating better discrimination of the distribution of L. dispar defoliation. Therefore, our approach to integrating satellite data and species distribution models can potentially enhance the assessment of areas affected by pests for effective forest management. [ABSTRACT FROM AUTHOR]

Environmental selection during early ontogeny influences plant species representation in mature vegetation. Chief amongst these selective forces is the interplay of herbivore selection and seedling defence/tolerance. Although some species can recover from almost complete cotyledon loss, it remains unclear whether tolerance is impacted by other critical early life-history hazards like competition. This study examines early seedling tolerance of two sympatric Plantago species (P. lanceolata and P. major) for individuals grown in isolation, monoculture (i.e., with conspecifics) and mixed assemblages (with congenerics). The effects of 95 and 50% cotyledon removal at 14-d-old on plant growth and root:shoot allocation was established in 28-d and 100-d old plants. Although damage and neighbour environment consistently limited subsequent growth of P. major, there was no interaction between these factors. Nonetheless, individuals subjected to 95% defoliation in mixed assemblages were substantially smaller than those without neighbours. A similar response to cotyledon removal was evident for P. lanceolata at 28-d, although plants with conspecific neighbours tended to be larger. The defoliation effect disappeared at 100-d, and plants grown with neighbours were now smaller. Mortality and root:shoot allocation did not vary across treatments. While we underscore the negative impact that early ontogenetic damage and the influence of neighbour environment has on subsequent plant growth, we failed to elucidate obvious interactions between these factors. Nonetheless, we highlight how the remarkable tolerance of Plantago seedlings to almost complete defoliation in the face of intra-/inter-specific competition, may yet be impacted by anthropogenic disruption of environmental filters operating at the regeneration stage. [ABSTRACT FROM AUTHOR]

This study quantifies the effects of wide row spacing on lint yield, yield components, and fiber quality of upland cotton (Gossypium hirsutum L.). An experiment was conducted in Tifton, GA in 2021 and 2022, where cotton was planted in six replications of 91‐, 122‐, 152‐, and 183‐cm row spacings. Following defoliation, 1.8 m was hand harvested from each plot, and boll density plant−1 and density ha−1 were determined for sympodial and monopodial branches. Additional measurements included fruit and lint yield distribution assessments and intra‐boll yield components including seed cotton weight boll−1, seed index, seed boll−1, lint weight seed−1, seed surface area (SSA), fiber density, and single fiber weight. Lint yield was reduced 20% in the 183‐cm row spacing compared to the 91‐cm row spacing. The 91‐cm rows had the lowest number of sympodial bolls plant−1 with 152‐ and 183‐cm rows demonstrating a 24%–28% increase in sympodial bolls plant−1. Sympodial bolls ha−1 were reduced 22% in the 183‐cm row spacing compared to the 91‐cm row spacing. There were no differences in bolls ha−1 or lint yield ha−1 with respect to monopodial growth. There were no differences in seed cotton weight boll−1, seeds boll−1, fiber density, single fiber weight, or turnout. Seed index and SSA were increased in the 183‐cm row spacing. Lint weight seed−1 was reduced in the 91‐cm row spacing. Core Ideas: Cotton produced in 152‐ and 183‐cm row spacings produces more sympodial bolls plant−1 than traditional 91‐cm rows.Sympodial bolls ha−1 were reduced in 183‐cm row spacings as compared to 91‐cm row spacings.With a reduction in sympodial bolls ha−1, lint yield is sacrificed in the 183‐cm row spacing.Wide row spacing improved fruit retention but did not affect lint yield.Even with more monopodial bolls plant−1 in the wider rows, there are no differences in monopodial bolls ha−1. [ABSTRACT FROM AUTHOR]

Fire damage can significantly impact fruit productivity in orchards. However, the effects of nonlethal fire injuries on the reproductive development of apple trees remain poorly understood. To investigate these effects, we implemented three treatments: trunk girdling to simulate fire injury to xylem, defoliation of a third of the canopy (simulated crown fire injury), and a combined treatment (simulated surface fire injury), alongside a control. The experiment was conducted during the 2021–22 growing season using a randomised block design with four biological replicate plots. Girdling was less effective than crown and surface fire treatments in influencing fruit composition during the current growing season, and flowering and fruiting in the following season. The crown and surface fire treatments induced localised detrimental effects on fruit sugar and titratable acidity while stimulating peel blush. Additionally, these treatments led to reduced starch reserves by harvest, which likely disrupted subsequent flowering and crop load near the previously defoliated sections of the canopy. When surface fires damage leaves near the base of the canopy in addition to the trunk, fruit production in the lower part of the canopy is more likely to be compromised in the following season. Crown fires, which cause leaf loss near the apex of the canopy, appear to be particularly detrimental to tree productivity, as the top defoliation treatment impaired carbohydrate reserves in shoot terminals and roots. In conclusion, fire-induced loss of leaf area during fruit growth alters fruit composition in the current growing season and may lead to lower yields in the subsequent season. [ABSTRACT FROM AUTHOR]

Extended Abstract Background: The Hyrcanus boxwood is the only type of boxwood in the Hyrcanus forests of Iran and one of the few evergreen broadleaf trees in the Hyrcanus forests. Today, boxwood is included in Iran's red list of endangered plants. On the one hand, a major part of the boxwood forests of the Hyrkani region have been destroyed due to the excessive exploitation of boxwood trees during the past decades. On the other hand, the occurrence of the boxwood leaf burn fungal disease and, more importantly, the outbreak of the boxwood moth pest have destroyed large areas of these forests (more than 80-90 percent of them). Due to the importance of the Caspian boxwood and its high value in terms of biodiversity, forest managers are trying to investigate factors affecting this pest in the forest ecosystem. The present study intends to investigate the effect of the boxwood moth pest on the above-below-ground vegetation in the two monitoring periods, namely 2010 and 2022 (before and after the boxwood moth pest outbreak, respectively) in the Buxus hyrcanus Pojark reserve in Sisangan. Methods: The above-ground vegetation was studied with the Braun-Blanquet method at peak vegetation cover by the systematic-selective method in 200 and 400-meter grid dimensions by considering the indicator stand concept in 2010 (and 2022 (before and after the moth pest outbreak, respectively). First, a list of all plant species was recorded in each sample plot by the vegetative form, and then the abundance and predominance of plant species were recorded based on the Brown-Blanke scale. Then, they were accurately identified using the available resources, including Flora Iranica, Persian Flora Collection of Iran, and Color Flora of Iran. The biological form of plants was determined based on the Rankier classification, followed by drawing the biological spectrum. This classification of plants is divided based on the location of regenerating buds where new branches and leaves originate after an unfavorable season. To investigate the geographical distribution or chorology of the plants, their distribution areas were first determined using the mentioned floral sources, and then the chorotypes of the species were divided based on the classification of geographical areas and toxic floristic areas. The geographical distribution spectrum of plants in the region was also drawn in the form of a histogram. Results: The results showed that 52 and 69 species in 2010 and 2022 were respectively identified in the Sisangan boxtree (B. hyrcanus Pojark) forest reserve. In 2010, Phanerophytes and Cryptophytes with 44% (23 species) and 19% (10 species) were the most present trees, respectively. In 2022, Phanerophytes and Trophytes with 38% (26 species) and 23% (16 species) were the most important biological spectrums, respectively. The results of examining species diversity, evenness, and species richness indices revealed a significant difference (P < 0.001) between the values of species diversity, evenness, and species richness indices in two monitoring periods (2010 and 2022). The indicators of species diversity, uniformity, and species richness of Rosemary cover were significantly different (P < 0.001/001) between the values of Rosemary species diversity, uniformity, and species richness indicators in two monitoring periods (2010 and 2022). In the examination of the degree of similarity between past and present vegetation of the Shamshad Sisangan Reservoir using Jaccard and Sorenson functions, the degree of similarity of Rosemary vegetation was small in the two monitoring periods. The occurrence of any natural disturbance in the forest communities causes a change in the sequence of vegetation and a decrease in the similarity between the vegetation before and after the disturbance. Therefore, the results of this research showed that species richness and diversity increased with the intensity of leaf-eating by the pest of boxwood moth and the opening of the canopy. Because the characteristics of the disturbance regimes strongly affect the dynamics and sequence of the forest, the use of a conservation management strategy can play an important role in reducing its effects. Conclusion: This research demonstrates that species richness and diversity increase with the intensity of defoliation by the boxwood pest and opening the canopy. Additionally, because the aboveground in the infected areas is often covered with pioneer and herbaceous species, management strategies should be prioritized to direct the succession path in this reservoir toward the climax stages.

The high demand for Maize encourages various agricultural innovations. The study aims to examine the effect of defoliation and P fertilizer application on the growth and production of the Madura 3 Maize variety which is grown in the close cropping system. This study used a randomized block design consisting of two factors with three replications. The parameters observed were stem diameter, root weight, cob fresh weight, cob dry weight, dry seed weight, and 100 seed weight. The results showed that there was a significant interaction between the defoliation factor and the dose of SP-36 on cob diameter, where the highest diameter (4,75 cm) was found in the combination of non-defoliation and SP-36 150 kg.ha-1. Overall, the non-defoliation of an SP-36 of 250 kg.ha-1 showed the best result on Maize growth and production. The addition of the dose of SP-36 also needs to pay attention to the needs of plants.

Introduction: Defoliation by applying defoliants before machine picking is an important agricultural practice that enhances harvesting efficiency and leads to increased raw cotton purity. However, the fundamental characteristics of leaf abscission and the underlying genetic basis in cotton are not clearly understood. Objectives: In this study, we aimed to (1) reveal the phenotypic variations in cotton leaf abscission, (2) discover the whole-genome differentiation sweeps and genetic loci related to defoliation, (3) identify and verify the functions of key candidate genes associated with defoliation, and (4) explore the relationship between haplotype frequency of loci and environmental adaptability. Methods: Four defoliation-related traits of 383 re-sequenced Gossypium hirsutum accessions were investigated in four environments. The genome-wide association study (GWAS), linkage disequilibrium (LD) interval genotyping and functional identification were conducted. Finally, the haplotype variation related to environmental adaptability and defoliation traits was revealed. Results: Our findings revealed the fundamental phenotypic variations of defoliation traits in cotton. We showed that defoliant significantly increased the defoliation rate without incurring yield and fiber quality penalties. The strong correlations between defoliation traits and growth period traits were observed. A genome-wide association study of defoliation traits identified 174 significant SNPs. Two loci (RDR7 on A02 and RDR13 on A13) that significantly associated with the relative defoliation rate were described, and key candidate genes GhLRR and GhCYCD3;1, encoding a leucine-rich repeat (LRR) family protein and D3-type cell cyclin 1 protein respectively, were functional verified by expression pattern analysis and gene silencing. We found that combining of two favorable haplotypes (HapRDR7 and HapRDR13) improved sensitivity to defoliant. The favorable haplotype frequency generally increased in high latitudes in China, enabling adaptation to the local environment. Conclusion: Our findings lay an important foundation for the potentially broad application of leveraging key genetic loci in breeding machine-pickable cotton.

The source-sink (S-S) ratio during the grain-filling period is crucial for wheat crop yield. The aim of this study was to investigate the relative sensitivity of grain yield in response to treatments of S-S ratio changes to determine the extent of SS limitation during grain filling in modern wheat genotypes. The S-S manipulation treatments included four levels: check (CH), removal of flag leaf (RFL), removal of all leaves (RAL), and removal of the upper half of the spikes (RHS). The results showed significant differences between genotypes (pb< 0.001%) in all traits. Drought stress decreased grain weight per spike (GWS) (g) and grain yield (GY) (kg/ha) by 18% and 25%, respectively. The average reduction in GWS under irrigation and rainfed conditions was 8.25% and 6.71% for RFL and 12.25% and 11.15% for RAL, respectively. By RFL and RAL, increasing the remobilization from the stem and spike straw helped to reduce the effects of source limitation. Also, by RHS, the reduction in photosynthetic materials production in both conditions was only equivalent to 38% and 29% of the expected values, respectively, which shows the presence of strong sinks in vegetative organs (stem and spike) compared to grains. Vegetative organs seem to have a larger sink for the uptake of photosynthetic materials than grains when the source-sink ratio increases. However, high-yield genotypes showed more severe source limitation, while low-yield genotypes showed more relative sink limitation. Overall, to increase the yield potential in high-yielding genotypes, photosynthetic sources and sinks in low-yielding genotypes should be improved. [ABSTRACT FROM AUTHOR]

Summary: Extreme droughts can have long‐lasting effects on forest community dynamics and species interactions. Yet, our understanding of how drought legacy modulates ecological relationships is just unfolding. We tested the hypothesis that leaf chemistry and herbivory show long‐term responses to premature defoliation caused by an extreme drought event in European beech (Fagus sylvatica L.).For two consecutive years after the extreme European summer drought in 2018, we collected leaves from the upper and lower canopy of adjacently growing drought‐stressed and unstressed trees. Leaf chemistry was analyzed and leaf damage by different herbivore‐feeding guilds was quantified.We found that drought had lasting impacts on leaf nutrients and on specialized metabolomic profiles. However, drought did not affect the primary metabolome. Drought‐related phytochemical changes affected damage of leaf‐chewing herbivores whereas damage caused by other herbivore‐feeding guilds was largely unaffected. Drought legacy effects on phytochemistry and herbivory were often weaker than between‐year or between‐canopy strata variability.Our findings suggest that a single extreme drought event bears the potential to long‐lastingly affect tree–herbivore interactions. Drought legacy effects likely become more important in modulating tree–herbivore interactions since drought frequency and severity are projected to globally increase in the coming decades. [ABSTRACT FROM AUTHOR]

This study assesses the impact of defoliation applied to three developmental stages across three cropping seasons from 2021 to 2023 on growth, yield and forage quality in maize. The experimental design included three treatments: defoliation of three expanded leaves at the 3rd–4th leaf stage (DF1), the 5th–6th expanded leaves by leaf punch (DF2) and expanding leaves with the DF2 treatment (DF3) at the 6th–7th leaf stages, compared with no defoliation (control). Over three years, the most significant decrease in dry matter (DM) yield occurred in DF1 during spring sowing, while in summer sowing, the largest reduction was in DF3, both of which were correlated with changes in the number of grains per ear. The DM yields at harvest were positively correlated with plant leaf areas at the silking stage. The digestibility of forage in in vitro DM decreased concomitantly with an increase in acid detergent fiber content, indicating a decrease in forage quality. Given the frequent severe damage observed in summer sown maize and the detrimental effects of early growth stage leaf feeding on quality and quantity of spring sown maize, the application of registered insecticides is advised to reduce pest damage to maize crops. [ABSTRACT FROM AUTHOR]

Forest trees adopt effective strategies to optimize nitrogen (N) use through internal N recycling. In the context of more recurrent environmental stresses due to climate change, the question remains of whether increased frequency of drought or defoliation threatens this internal N recycling strategy. We submitted 8-year-old beech trees to 2 years of either severe drought (Dro) or manual defoliation (Def) to create a state of N starvation. At the end of the second year before leaf senescence, we labeled the foliage of the Dro and Def trees, as well as that of control (Co) trees, with 15N-urea. Leaf N resorption, winter tree N storage (total N, 15N, amino acids, soluble proteins) and N remobilization in spring were evaluated for the three treatments. Defoliation and drought did not significantly impact foliar N resorption or N concentrations in organs in winter. Total N amounts in Def tree remained close to those in Co tree, but winter N was stored more in the branches than in the trunk and roots. Total N amount in Dro trees was drastically reduced (−55%), especially at the trunk level, but soluble protein concentrations increased in the trunk and fine roots compared with Co trees. During spring, 15N was mobilized from the trunk, branches and twigs of both Co and Def trees to support leaf growth. It was only provided through twig 15N remobilization in the Dro trees, thus resulting in extremely reduced Dro leaf N amounts. Our results suggest that stress-induced changes occur in N metabolism but with varying severity depending on the constraints: within-tree 15N transport and storage strategy changed in response to defoliation, whereas a soil water deficit induced a drastic reduction of the N amounts in all the tree organs. Consequently, N dysfunction could be involved in drought-induced beech tree mortality under the future climate. [ABSTRACT FROM AUTHOR]

One of the key ecosystem services offered by avian biodiversity within agricultural landscapes is natural predation. Nonetheless, the current use of biological control agents such as farmland birds in oil palm plantations is relatively limited.This study aimed to assess the potential roles of avian biodiversity, particularly insectivores that provide natural predation against oil palm herbivorous insects. We also investigated the influence of local‐ and landscape‐scale variables on foliage damage (crown or frond).Our data showed that crown damage decreased with increasing farmland bird richness (overall and insectivore), shrub cover, dried biomass and elevation, but increased with epiphyte cover, oil palm height and distance to continuous forest. Frond damage was negatively related to bird richness (overall, insectivore and non‐insectivore) and non‐insectivore abundance, elevation and shrub cover, while increased with insectivorous abundance, epiphyte cover, oil palm height and distance to continuous forest. We also found that plantations (≥50 ha) were more susceptible to foliage damage from pest insects than smallholdings (<50 ha).There was no evidence that indicate the influence of forest patches on foliage damage.Synthesis and applications. Our study highlights the economic value of conserving biodiversity, most notably, farmland birds and continuous forests with respect to biological control of defoliating pests and maintaining yield productivity in oil palm cultivation. Growers, particularly major plantation companies should make oil palm farming more biodiversity‐friendly in order to increase the number of biological control agents such as birds. [ABSTRACT FROM AUTHOR]

Insect defoliation is a widespread cause of forest disturbance in Canada, and it has the potential to alter terrestrial carbon contributions to stream consumers and thus affect stream ecosystems. Although defoliation by spruce budworms (Choristoneura fumiferana) is considered a natural disturbance with importance to forest succession, the magnitude and duration of outbreaks are increasing, and there is a growing need to understand their downstream consequences. To examine this, algal productivity and autochthonous (in-stream) energy supporting macroinvertebrate and fish consumers (using δ13C, δ15N) were examined in 12 streams in the Gaspé Peninsula, Québec, Canada, that ranged in watershed defoliation from spruce budworm. Hierarchical partitioning models were used to assess the contributions of watershed and stream variables to these endpoints. Total seasonal algal production ranged fourfold among sites, and cumulative defoliation was the strongest predictor. Consumers from streams with greater defoliation (cumulative or annual) had lower reliance on autochthonous carbon, despite increased algal production, and this effect was greater for brook trout than macroinvertebrates. These findings demonstrate for the first time that insect outbreaks—which alter forest structure and function—also similarly affect downstream aquatic ecosystems by causing changes in the production and contributions of carbon sources. This suggests that insect control strategies and forest management decisions should also consider implications for downstream aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Phytoregulators have been used as grapevine defoliants in cluster zones to manage and improve grape quality and production. The present study evaluated the effect of the phytoregulator ethephon on the grapevine defoliation of the cluster region, Botrytis bunch rot (BBR) epidemiology, and the viticultural performance of 'Cabernet Sauvignon', during the 2018/2019 and 2019/2020 growing seasons, in the highland region of the Santa Catarina State, Southern Brazil. Ethephon was applied in the bunch region of both sides of the grapevine vegetative canopy, at the phenological stage of beginning of ripening (BBCH-81) in five active ingredient doses (0 mg L-1 (control); 720 mg L-1; 1,440 mg L-1; 2,160 mg L-1; and 2,880 mg L-1), following a randomized block design with four replications and five plants per replication. The following parameters were evaluated: BBR epidemiology, vegetative, productive, and technological and phenolic maturation. The increasing ethephon doses significantly reduced the linear leaf drop and affected the technological and phenolic grape maturation parameters, improving the must pH, total polyphenols, color 420, 520, and 620 m, color intensity (°hue angle), and anthocyanin, and reducing the total solubre solids in the 'Cabernet Sauvignon' grapevine. However, this significant effect on the linear leaf drop and the technological and phenolic maturation parameters did not interfere with other vegetative, productive, and BBR epidemiology parameters evaluated in the edaphoclimatic conditions of the highland region of southern Brazil. [ABSTRACT FROM AUTHOR]

The non-native invasive box-tree moth Cydalima perspectalis causes severe damage to ornamental box trees (Buxus spp.) and natural boxwood stands. So far, no promising natural enemy of C. perspectalis has been discovered in Europe. Many garden owners would like to protect their box trees from C. perspectalis without the use of insecticides, which also harm other arthropod species. In a controlled experiment under natural conditions, we tested whether box trees covered with a net during the flight period of C. perspectalis are as well protected against the moth as trees treated with a bioinsecticide. After 1 year, the box trees covered with a net during the moths' flight activity (monitored by light traps) showed no damage by larvae (average loss of leaves 0%), as did box trees regularly treated with a bioinsecticide (control group 1). In contrast, box trees with no protection (untreated box trees; control group 2) lost 97.7% of their leaves due to larval feeding. In a second experiment, we investigated whether defoliated box trees can recover when covered with a net during the flight period of the moth. Protected by the net, the emerging new leaves were not attacked by C. perspectalis. After 1.5 years, the trees had 24% of their original foliage again. Our study demonstrates that temporarily covering box trees with a net protects them against damage by C. perspectalis in an effective way. [ABSTRACT FROM AUTHOR]

Forest ecosystems within national parks are threatened by various biotic and abiotic factors. To determine the causes of the desiccation and death of trees in mixed coniferous and deciduous forests of Tara National Park (TNP), Serbia, we monitored defoliation and mortality of individual trees in permanent experimental plots. Data on the desiccation of a large number of trees were gathered by determining the total volume of dry trees and areas of forests under drying stress. The two sets of data were combined to determine the impact of climatic events, primarily drought periods, on the desiccation of forests. Combining data from the International Co-operative Program on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) with TNP data helped relate forest desiccation to climate events. Key climate signals were identified by monitoring tree defoliation changes in two permanent experimental plots, and then assessed for their influence on tree desiccation in the entire national park. The standardized precipitation evapotranspiration index (SPEI) was used for a more detailed analysis of the drought period. Despite the lack of climate data for a certain period, the SPEI index revealed a link between climate variables and the defoliation and desiccation of forests. Furthermore, the desiccation of trees was preceded by a long drought period. Although mixed coniferous-deciduous forests are often considered less vulnerable to natural influences, this study suggests that forest ecosystems can become vulnerable regardless of tree species composition due to multi-year droughts. These findings contribute to a better understanding of important clues for predicting possible future desiccation of forests. Continuous monitoring of the state of forests and of more permanent experimental plots in national parks could provide better quality data and timely responses to stressful situations. [ABSTRACT FROM AUTHOR]

Defoliation is an inevitable abiotic stress for forage and turf grasses because harvesting, grazing, and mowing are general processes for their production and management. Vegetative regrowth occurs upon defoliation, a crucial trait determining the productivity and persistence of these grasses. However, the information about the molecular regulation of this trait is limited because it is still challenging to perform molecular analyses in forage and turf grasses. Here, we used rice as a model to investigate vegetative regrowth upon defoliation at physiological and molecular levels. This study analyzed stubble and regrown leaves following periodic defoliation using two rice varieties with contrasting regrowth vigor. Vigorous regrowth was associated with maintained chlorophyll content and photosystem II performance; a restricted and promoted mRNA accumulation of sucrose synthase (SUS) I and III subfamilies, respectively; and reduced enzymatic activity of SUS. These results suggest that critical factors affecting vegetative regrowth upon defoliation are de novo carbohydrate synthesis by newly emerged leaves and proper carbohydrate management in leaves and stubble. Physiological and genetic analyses have demonstrated that the reduced sensitivity to and inhibited biosynthesis of cytokinin enhance regrowth vigor. Proper regulation of these metabolic and hormonal pathways identified in this study can lead to the development of new grass varieties with enhanced regrowth vigor following defoliation. [ABSTRACT FROM AUTHOR]

The preservation or removal of apical meristem in Leymus chinensis is contingent upon grazing intensity and has a significant impact on above‐ and belowground biomass, nutritive value, and sustainability of L. chinensis grassland. However, this topic remains understudied. Therefore, a manipulative trial was conducted to induce grazing defoliation through mowing, where two post‐grazing heights (preservation or removal of the apical meristem) and four pre‐grazing plant heights (i.e., 18, 24, 31, and 35 cm) are combined factorially to create gradients of grazing intensities, resulting in a total of eight treatments. Additionally, two identical control treatments are also incorporated. Our results showed that apical meristem removal at various pre‐grazing heights resulted in varying degrees of increased grazing intensities, thereby enhancing the nutritive value of L. chinensis. However, this practice also led to detrimental effects on the plant's carbohydrates reserve as well as herbage mass. The results indicated that although defoliation in treatments involving apical meristem removal resulted in the highest number of frequent cuttings, it did not confer any advantages in terms of herbage mass and nutrient preserves, except for herbage nutritive values when compared to treatments involving apical meristem preservation. The apical meristem preservation treatments demonstrated the highest CP yield over a 2‐year period compared to the apical meristem removal treatments. Furthermore, within these apical meristem preservation treatments, only when the pre‐grazing height is 35 cm and post‐grazing height is 17 cm, there is no significant decrease in above‐ and belowground biomass. This establishes this specific defoliation regime as an optimal and effective management strategy for L. chinensis grassland. [ABSTRACT FROM AUTHOR]

Plants face a trade‐off between hydraulic safety and growth, leading to a range of water‐use strategies in different species. However, little is known about such strategies in tropical trees and whether different water‐use traits can acclimate to warming. We studied five water‐use traits in 20 tropical tree species grown at three different altitudes in Rwanda (RwandaTREE): stomatal conductance (gs), leaf minimum conductance (gmin), plant hydraulic conductance (Kplant), leaf osmotic potential (ψo) and net defoliation during drought. We also explored the links between these traits and growth and mortality data. Late successional (LS) species had low Kplant, gs and gmin and, thus, low water loss, while low ψo helped improve leaf water status during drought. Early successional (ES) species, on the contrary, used more water during both moist and dry conditions and exhibited pronounced drought defoliation. The ES strategy was associated with lower mortality and more pronounced growth enhancement at the warmer sites compared to LS species. While Kplant and gmin showed downward acclimation in warmer climates, ψo did not acclimate and gs measured at prevailing temperature did not change. Due to distinctly different water use strategies between successional groups, ES species may be better equipped for a warmer climate as long as defoliation can bridge drought periods. [ABSTRACT FROM AUTHOR]

Source‐sink balance in plants determines carbon distribution, and altering it can impact carbon fixation, transport, and allocation. We aimed to investigate the effect of altered source‐sink ratios on carbon fixation, transport, and distribution in 'Valencia' sweet orange (Citrus x sinensis) by various defoliation treatments (0%, 33%, 66%, and 83% leaf removal). Gas exchange parameters were measured on 0 and 10 days after defoliation using A/Ci response curves, and leaf export was measured two days after defoliation using radioisotope tracer techniques. Greater defoliation increased the maximum rate of carboxylation (Vcmax), electron transport rate (J1200), and triose‐phosphate utilization rate (TPU). Leaf export was unaffected by defoliation but increased in leaves closer to the shoot apex. Basipetal translocation velocity in the trunk remained unaltered, indicating that more photosynthates remained in the shoot rather than being transported directly to the root sink. Defoliated plants initiated more new flush shoots but accumulated less shoot biomass per plant after 8 weeks. Carbon allocation to fine roots was smaller in defoliated plants, suggesting defoliation led to retention of carbohydrates in aboveground organs such as the trunk and other shoots from previous growing cycles. In conclusion, the low source‐sink ratio increased carbon fixation without impacting individual leaf export in citrus. The results suggest that intermediate sinks such as the aboveground perennial organs play a role in mediating the translocation velocity. Further research is necessary to better understand the dynamics of source‐sink regulation in citrus trees. [ABSTRACT FROM AUTHOR]