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Productivity in strawberry is dependent on carbon assimilation in the leaves. The main scenarios for climate change include an increase in the concentration of CO2 in the atmosphere and an increase in temperature. This review examined the relationship between leaf growth and temperature in strawberry. Leaf growth follows a linear, sigmoid or Gaussian pattern over the season or is variable depending on the weather. There was a linear increase in leaf growth with temperatures below 26°C, and a linear decrease in growth with temperatures above 26°C. In other studies, the mean lower optimum for 90% of maximum growth was 18.3° ± 3.9°C, the median was 19.6°C, and the range was from 7.2° to 22.0°C (N = 11). The mean higher optimum was 27.3° ± 3.6°C, the median was 27.4°C, and the range was from 21.1° to 33.5°C (N = 12). Leaf growth was higher under 30°C and lower above 30°C. Limited studies suggest that elevated CO2 will not counteract the impact of high temperatures on growth. Climate change will increase leaf growth in cool areas and decrease growth in warm areas. The decrease in leaf growth in locations with temperatures above 30°C will contribute to lower yields under global warming. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the bioherbicidal effect of aqueous fresh extracts of leaves and roots of the Aloe vera plant on the broad leaf weed growth of Sonchus oleraceus associated faba bean plants. During the winters of 2020/2021 and 2021/2022, two pot experiments were carried out in the greenhouse of the National Research Center. Leaf and root aqueous extracts of Aloe vera were applied as soil and/or spray treatments at different concentrations. The results showed that there was significant inhibition in the fresh and dry biomass of S. oleraceus and was maximum with application of soil treatment (10%) of the leaf extract sequenced by spraying leaf extract at 20%. Furthermore, the inhibition of the weed growth was accompanied by an increase in the growth and yield of faba bean. The results indicated that phenols, flavonoids, alkaloids, tannins and saponins were present in the leaf extract, and there were smaller amounts of tannins and saponins in the root extract than in the leaf extract. Total phenols, flavonoids, alkaloids in the leaf extract was more than three times that of the root extract. The results also revealed that the presence of higher concentrations of natural substances in the leaf extract than in the root extracts gave it its efficiency in inhibiting the growth of S. oleraceus weeds. [ABSTRACT FROM AUTHOR]

Morphological changes of sugar beet leaves in vegetative growth were monitored in the 2014 and 2015 growing seasons. In both years leaf samples were collected on 6 dates from late May to September at 20-day intervals, therefore more than 12,000 leaves were measured. On 20 August, the most common leaf length (309 leaves) ranged from 48.7 to 51.3 cm, petiole length was between 20.0 and 21.7 cm (274 leaves) and single leaf area (278 leaves) was between 117 and 139 cm² (278 leaves). The most common leaf blade width was recorded on 10 July, and it ranged from 10.1 to 10.8 cm (279 leaves). Linear regression showed a highly significant relation¬ship for leaf blade length and leaf area (R² = 0.55, p <0.001), leaf blade width and leaf area (R² = 0.87, p < 0.001) and leaf petiole length and leaf area (R² = 0.18, p <0.001). Thus, leaf blade width was the best parameter for predicting leaf area. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The contribution of plant hormones and energy-rich compounds and their metabolites (ECMs) in alleviating aluminum (Al) toxicity by elevated pH remains to be clarified. For the first time, a targeted metabolome was applied to identify Al-pH-interaction-responsive hormones and ECMs in Citrus sinensis leaves. More Al-toxicity-responsive hormones and ECMs were identified at pH 4.0 [4 (10) upregulated and 7 (17) downregulated hormones (ECMs)] than those at pH 3.0 [1 (9) upregulated and 4 (14) downregulated hormones (ECMs)], suggesting that the elevated pH improved the adaptation of hormones and ECMs to Al toxicity in leaves. The roles of hormones and ECMs in reducing leaf Al toxicity mediated by elevated pH might include the following aspects: (a) improved leaf growth by upregulating the levels of jasmonoyl-L-isoleucine (JA-ILE), 6-benzyladenosine (BAPR), N6-isopentenyladenosine (IPR), cis-zeatin-O-glucoside riboside (cZROG), and auxins (AUXs), preventing Al toxicity-induced reduction of gibberellin (GA) biosynthesis, and avoiding jasmonic acid (JA)-mediated defense; (b) enhanced biosynthesis and accumulation of tryptophan (TRP), as well as the resulting increase in biosynthesis of auxin, melatonin and secondary metabolites (SMs); (c) improved ability to maintain the homeostasis of ATP and other phosphorus (P)-containing ECMs; and (d) enhanced internal detoxification of Al due to increased organic acid (OA) and SM accumulation and elevated ability to detoxify reactive oxygen species (ROS) due to enhanced SM accumulation. To conclude, the current results corroborate the hypotheses that elevated pH reduces Al toxicity by upregulating the ability to maintain the homeostasis of ATP and other P-containing ECMs in leaves under Al toxicity and (b) hormones participate in the elevated pH-mediated alleviation of Al toxicity by positively regulating growth, the ability to detoxify ROS, and the internal detoxification of Al in leaves under Al toxicity. Our findings provide novel insights into the roles of hormones and ECMs in mitigating Al toxicity mediated by the elevated pH. • Elevated pH improved the adaptation of hormones and ECMs to Al in citrus leaves. • Elevated pH enhanced the homeostasis of leaf ATP and other P-containing ECMs. • Elevated pH increased auxin, melatonin and secondary metabolite synthesis in leaves. • Elevated pH enhanced leaf abilities of internal Al detoxification and ROS removal. [ABSTRACT FROM AUTHOR]

Tea tree is a fluorine (F)-enriched plant, leading to much concern about the safety of drinking tea from tea tree (Camellia sinensis (L.) Kuntze). Tea tree is a perennial leaf-harvested crop, and tea production in China is generally categorized as spring tea, summer tea and autumn tea in its annual growth rounds. However, the seasonally dynamic changes of F content and accumulation in the leaves and its drinking safety are poorly understood. In this study, 85 tea varieties cultivated under the same conditions were investigated to analyze the seasonal variation of F content and it's relationships with F accumulation, aluminum (Al), calcium (Ca) and manganese (Mn) and hazard quotient (HQ) in young leaves (one bud and two leaves, YL) and mature leaves (canopy leaves, ML). The average F contents and accumulations were 350 mg kg−1 and 203 g ha−1 in YL, and they were 2451 mg kg−1 and 2578 g ha−1 in ML, respectively, with F mainly accumulated in ML. As the growing season progresses, the F content showed a gradual increase in YL, while a decrease in ML, inferring that F may be redistributed from mature leaves to young leaves. Additionally, the F content was quite different among tea varieties which are suitable for processing oolong tea, green tea, and black tea, with higher F accumulation in oolong tea varieties than in green and black tea varieties. Moreover, F content and accumulation could be obviously affected by the geographical origin of the tea tree varieties, with significantly higher F content in the varieties from F rich fluorite belts than other regions. Furthermore, F content and accumulation showed a significant positive correlation with the content of Al and Mn (p < 0.05). Based on a daily tea consumption of 8.7 g, the HQ was investigated to show that the proportion of tea leaves with HQ<1 made from spring, summer and autumn tender leaves of 85 varieties was 100 %, 90.6 % and 50.6 %, respectively, indicating that the tea with the best drinking safety comes from spring, followed by summer, and then autumn. This result suggests that it could be necessary to avoid planting tea trees in fluorite mining areas, choose low F tea tree varieties, and control the tenderness of fresh leaves in order to ensure the safety of tea drinking. • Fluorine (F) accumulation of 85 tea varieties in one growth cycle is studied. • The 85 tea varieties show a notable difference in genotype and F features. • F mainly accumulates in mature leaf and distributes to young leaf during growth. • F accumulation is related to tea suitability and leaf content of Al, Mn and Ca ions. • Young leaf tea has less hazard quotient and is safe for long-term drinking. [ABSTRACT FROM AUTHOR]

To optimize integrated weed management, it is essential to understand the competitive ability of maize hybrids with new traits when coexisting with the weed community. Thus, the aim of this study was to evaluate the competitive ability of the maize against E. indica and D. insularis weeds under greenhouse (controlled conditions) and in the field by additive and replacement series designs, with different densities for each condition. In greenhouse experiments, maize coexisting with E. indica resulted in negative relative growth for leaf area and shoot dry mass, indicating damage to both species. However, maize with D. insularis did not exhibit negative relative growth, suggesting a different interaction. The analysis of relative competitiveness and aggressiveness revealed significant values for maize with D. insularis , indicating a competitive relationship. In contrast, maize with E. indica showed non-significant values, suggesting a less competitive interaction. In field experiments, the full model and reduced models showed good fit to the data, with non-significant differences between them, indicating that the interference of these weed species on maize yield were similar. The Principal Component Analysis identified four principal components. For PCs 1 and 2, chlorophyll-related variables exhibited a high relative contribution, showing a positive correlation with cases involving high density of D. insularis. Variables related to ear insertion height, plant height, stem diameter, and stand of plants had greater relative importance for PC 1, especially for cases with higher density of E. indica. This highlights the resilience of maize to competitive conditions and suggests that its capacity for rapid growth in height makes this crop effective in competition for light, even against other C4 species. • The weed competition pattern is influenced by the environment in which the experiment is carried out. • E. indica has greater competitive ability than the D. insularis in low density. • Principal component analysis indicates that morphophysiological variables were affected differently depending on the weed. [ABSTRACT FROM AUTHOR]

Abstract The controlled-release fertilizers (CRFs) are the fertilizers which gradually release their mineral nutrients, while at the same time providing proper nutrition to the plants. The CRFs have been widely used to improve crops' quality and quantity, but have not been applied on Freesia hybrida so far. In this study, Freesia 'Shangnong Ruxiang' was used to determine the effect of CRFs on its vegetative and reproductive growth. Two different kinds of commercial CRFs i.e. Osmocote Classic and Agroblen were applied in various doses. In an appropriate dose, Osmocote Classic and Agroblen improved the growth of Freesia. The overall effect of Agroblen is better than Osmocote. Under treatments of 5 g/L Osmocote and 5 g/L or 7 g/L Agroblen, the plant height, scape height, scape number, scape strength, and chlorophyll content were higher than other groups. Under 7 g/L Agroblen, the plants blossomed 10 days earlier than that of control. Taken together, 5 g/L of Osmocote and 5 g/L or 7 g/L of Agroblen are recommended for strong leaf and corm growth with good flowering phenotype, while 5 g/L or 7 g/L of Agroblen only is optimum for early flowering in Freesia. [ABSTRACT FROM AUTHOR]

The recent labeling of a new fungicide and rumors of non-fungicidal 'plant health' benefits achieved through early-season foliar applications of certain fungicides have led to inquiries concerning the practice. The objective of this research was to determine the impact of an earlyseason fungicide application on early-season growth or end-of-season lint yields, turnout, and/or fiber quality when disease symptoms are not present. During the 2014-2016 growing seasons, a total of ten trials were established in Alexandria, LA; Starkville, MS; Fort Cobb, OK; Jackson, TN; and Snook, TX. Fungicide treatments included an untreated control, a foliar application of 0.11 kg ai ha-1 azoxystrobin, and a foliar application of 0.07 kg ai ha-1 fluxapyroxad + 0.15 kg ai ha-1 pyraclostrobin. All treatments targeted the two through four true leaf growth stage. A significant interaction between fungicide treatment and siteyear was observed from node counts collected at 14 and 28 DAA. Site-year analysis indicated a significant reduction in node counts observed with the azoxystrobin treatment in one site-year in the 14 DAA data and one site-year in the 28 DAA data. Fungicide treatment did not impact plant height or vigor ratings collected at 14 or 28 DAA, chlorophyll meter readings, lint yield, turnout, or fiber quality parameters in any siteyear. Failure of fungicide treatments to positively impact in-season growth measurements, yield, and yield parameters suggests the evaluated fungicides should not be applied early-season for the purpose of improving 'plant health' and should instead be reserved to target above-threshold levels of disease incidence/severity. [ABSTRACT FROM AUTHOR]

To clarify the interference effects of inorganic ions, Acorus tatarinowii and endophytic bacterium Herbaspirillum huttiense (Hh) were combined to decontaminate atrazine pollution under different copper levels. This study verified inoculation effects and revealed the complicated processes of atrazine transformation in solutions. 35.9% leaf biomass was promoted by Hh inoculation, and the value was lowered to 7.87% by high doses of copper. The changing trend of leaf N, K, and S contents, and tiller numbers were consistent with that of leaf biomass. Hh injection improved atrazine accumulation by 43.5% in roots, and under copper interference, this value lowered to 10.6%. Hh promoted atrazine deethylation in plants, which was copper-dose dependent in different plant organs. In solutions, atrazine was conjugated with small-molecule secretions at m/z 118, detoxicated into 2-hxydroatrazine and 2-hydroxy-4-acetamido-atrazine, then the triazine ring opened. Copper interference had a more significant impact on residual atrazine conversion products than Hh inoculation treatments. Hh treatment promoted the ring-opening degradation of atrazine in water. The addition of high doses of copper ions promoted the oxidative process of atrazine while inhibiting its ring-opening transformation process in water. [Display omitted] • Bacterial inoculation enhanced plant leaf growth, especially at low levels of copper. • Bacterial inoculation promoted atrazine store in roots, affected by copper levels. • Bacteria promoted atrazine detoxification in leaves, especially when copper was high. • Triazine ring of atrazine in solutions was opened, enhanced by endophytic bacteria. • High-level Cu and bacteria had opposite effects on atrazine oxidation in solutions. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) can pose high risk to living organisms due to their very small sizes. This study selected polyvinyl chloride MPs (PVC-MPs) which experienced up to 1000 h UV light radiation to investigate the influence of PVC-MPs on Brassica rapa growth. The outcomes showed the presence of PVC-MPs inhibited the plants' growth. The stem length, root length, fresh weight and dry weight of plants exposed to PVC-MPs after 30 days reduced by 45.9%, 35.2%, 26.1% and 5.2%, respectively. The chlorophyll, soluble sugar, malondialdehyde (MDA) and catalase (CAT) concentrations for plants exposed to PVC-MPs after 30 days increased by 25.9%, 135.7%, 88.7% and 47.1% respectively. It was also observed that PVC-MPs blocked the plants' leaf stomata and even entered plants' bodies. This might lead to PVC-MPs movement within the plants and influence plants' growth. The transcriptomic analysis results indicated that exposure to PVC-MPs up-regulated metabolic pathway of plant hormone signal transduction of the plants and down-regulated pathway network of ribosome. However, the research outcomes also showed that the PVC-MPs' locations in soil (located at the upper layers or at lower layers) and the UV light radiation time did not exert significantly different influences on inhibiting plants' growth. This can be attributed to PVC-MPs' small sizes and not much decomposition under light radiation. These imply that longer light radiation time and different particle sizes should be included into future research in order to further explore photodegraded MPs' toxicity effects on plants. [Display omitted] • Polyvinyl chloride microplastics (PVC-MPs) inhibited growth of Brassica rapa • PVC-MPs blocked leaf stomata • Exposure to PVC-MPs up-regulated plant hormone signal transduction related genes • Exposure to PVC-MPs down-regulated ribosome pathway networks [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is an emerging pollutant of environmental concern, classified as “moderately toxic” and “toxic”, causing adverse effects on aquatic biota. Although information about BPA toxicity on aquatic fauna is available, the data about BPA effects on aquatic flora remain scarce, missing for marine macrophytes. The effects of environmentally relevant BPA concentrations (ranging from 0.03 to 3 μg L −1 ) on juvenile leaf elongation and the cytoskeleton (microtubules, MTs and actin filaments, AFs) were studied in the seagrass Cymodocea nodosa for 1–10 days. The suitability of cytoskeleton disturbance and leaf elongation impairment as “biomarkers” for BPA stress were tested. The highest BPA concentrations (0.3, 0.5, 1 and 3 μg L −1 ) affected significantly leaf elongation from the onset of the experiment, while defects of the cytoskeleton were observed even at lower concentrations. In particular, MTs were initially disrupted (i.e. “lowest observed effect concentrations”, LOECs) at 0.1 μg L −1 , while AFs were damaged even at 0.03 μg L −1 . AFs appeared thus to be more sensitive to lower BPA concentrations, while there was a correlation between leaf elongation impairment and MT defects. Thus, AF damages, MT disruption and leaf elongation impairment in C. nodosa , in this particular order, appear to be sensitive “biomarkers” of BPA stress, at the above environmentally relevant BPA concentrations. [ABSTRACT FROM AUTHOR]

The frequency and intensity of heat stress events globally have increased over the past 20 years. Climatic modeling predicts that this trend will continue throughout the 21st century, with the global land area experiencing heat waves doubling by 2020 and quadrupling by 2040. Due to the reflective nature of buildings and infrastructure, heat temperatures tend to be higher within urban landscapes than outlying rural areas. Heat stress influences processes from the molecular level to whole-tree biology. At the leaf level, photosynthesis is reduced, photo-oxidative stress increases, premature leaf abscission occurs, and the growth of leaves decreases. Growth decreases at the whole tree level, and biomass allocation between roots, shoots, leaves, and branches is altered. When drought and heat stress are combined, detrimental effects are considerably enhanced and, without irrigation, can quickly lead to tree death. There have been few studies regarding the heat tolerance of urban tree species. However, there is evidence of genetic variation in heat tolerance between and within species within forestry, which could be essential to exploit for urban trees. Understanding the mechanisms of tree physiological, biochemical, and molecular responses to extreme heat events is also necessary for understanding how urban tree species will be affected by climate change. [ABSTRACT FROM AUTHOR]

Biological tissues acquire various characteristic shapes through morphogenesis. Tissue shapes result from the spatiotemporally heterogeneous cellular activities influenced by mechanical and biochemical environments. To investigate multicellular tissue morphogenesis, this study aimed to develop a novel multiscale method that can connect each cellular activity to the mechanical behaviors of the whole tissue by constructing continuum-based particle models of cellular activities. This study proposed mechanical models of cell growth and proliferation that are expressed as volume expansion and cell division by extending the material point method. By simulating cell hypertrophy and proliferation under both free and constraint conditions, the proposed models demonstrated potential for evaluating the mechanical state and tracing cells throughout tissue morphogenesis. Moreover, the effect of a cell size checkpoint was incorporated into the cell proliferation model to investigate the mechanical behaviors of the whole tissue depending on the condition of cellular activities. Consequently, the accumulation of strain energy density was suppressed because of the influence of the checkpoint. In addition, the whole tissues acquired different shapes depending on the influence of the checkpoint. Thus, the models constructed herein enabled us to investigate the change in the mechanical behaviors of the whole tissue according to each cellular activity depending on the mechanical state of the cells during morphogenesis. [Display omitted] • A multiscale simulation method was developed to analyze tissue morphogenesis caused by cells. • Tissue mechanical behaviors were analyzed based on continuum-based particle models. • Individual cell growth and division were explicitly expressed using particles. • The mechanical effect of a cell size checkpoint in a cell cycle was examined. • The models enabled cell tracing within the tissue during morphogenesis. [ABSTRACT FROM AUTHOR]

Simulation has become an important tool for studying plant physiology. An important aspect of this is discovering the processes that influence leaf growth at a cellular level. To this end, we have extended an existing, morphogen-based model for the growth of Arabidopsis leaves. We have fitted parameters to match important leaf growth properties reported in experimental data. A sensitivity analysis was performed, which allowed us to estimate the effect of these different parameters on leaf growth, and identify viable strategies for increasing leaf size. [ABSTRACT FROM AUTHOR]

In this Tamm review, we trace the origin and application of two production indices: Light Use Efficiency ( LUE ) and (Leaf) Growth Efficiency ( GE ). Light Use Efficiency usually denoted (ε) was originally defined by John Monteith in the 1970s as the rate that dry matter is accumulated by plants in relation to the amount of solar radiation absorbed by leaves; the concept has been a corner-stone of the field of production ecology ever since. Although highly variable at daily intervals, LUE becomes linear at longer intervals, providing a major simplification to the construction and application of process-based models. A further simplification in model construction became possible when it was found that the ratio between total dry mass production and gross photosynthesis is approximately constant (≈0.5). Simplified process-based models provide a means of estimating the maximum productivity of a species growing inside or outside its native range, and help to identify constraints on production in current and projected environments. Consequently, models that incorporate LUE have expanded from research tools to practical ways of assessing silvicultural options in the management of individual forests as well as for measuring and forecasting global trends in forest productivity. The Leaf Growth Efficiency ( GE ) index, defined as annual growth in stemwood per unit of leaf area, has become widely adopted as a means of identifying the spatial variation among trees, which affects stand growth and LUE . GE was originally used to assess the vulnerability of individual trees to attack by bark beetles but, combined with structural and physiological analyses it has been found useful for interpreting and predicting stand growth responses to tree spacing, aging, and defoliation. Challenges remaining in the field of forest production ecology include prediction of the effects of fast-changing climatic conditions across the globe on the growth and survival of species, and their interactions with continually rising atmospheric concentrations of CO 2 . [ABSTRACT FROM AUTHOR]

The promising response of chromium-stressed (Cr(VI)–S) plants to hydrogen sulphide (H 2 S) has been observed, but the participation of nitric oxide (NO) synthesis in H 2 S-induced Cr(VI)–S tolerance in plants remains to be elucidated. It was aimed to assess the participation of NO in H 2 S-mediated Cr(VI)–S tolerance by modulating subcellular distribution of Cr and the ascorbate-glutathione (AsA-GSH) cycle in the pepper seedlings. Two weeks following germination, plants were exposed to control (no Cr) or Cr(VI)–S (50 μM K 2 Cr 2 O 7) for further two weeks. The Cr(VI)–S-plants grown in nutrient solution were supplied with 200 μM sodium hydrosulphide (NaHS, donor of H 2 S), or NaHS plus 100 μM sodium nitroprusside (SNP, a donor of NO). Chromium stress suppressed plant growth and leaf water status, while elevated proline content, oxidative stress, and the activities of AsA-GSH related enzymes, as well as endogenous H 2 S and NO contents. The supplementation of NaHS increased Cr accumulation at root cell walls and vacuoles of leaves as soluble fraction to reduce its toxicity. Furthermore it limited oxidative stress, improved plant growth, modulated leaf water status, and the AsA-GSH cycle-associated enzymes' activities, as well as it further improved H 2 S and NO contents. The positive effect of NaHS was found to be augmented on those parameters in the CrS-plants by the SNP supplementation. However, 0.1 mM cPTIO, the scavenger of NO, inverted the prominent effect of NaHS by decreasing NO content. The supplementation of SNP along with NaHS + cPTIO reinstalled the positive effect of NaHS by restoring NO content, which suggested that NO might have a potential role in H 2 S-induced tolerance to Cr(VI)–S in pepper plants by stepping up the AsA-GSH cycle. [ABSTRACT FROM AUTHOR]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cadmium (Cd) damages plant photosynthesis, affects roots and leaves growth, and triggers molecular responses. Riluzole (RIL), which protected neuronal damage via inhibiting excess Glu release in animals, has been found to improve Cd tolerance in duckweed in this study. Firstly, RIL treatment alleviated leaf chlorosis by protecting chlorophyll and decreased root abscission under Cd stress. Secondly, RIL declines Cd accumulation by alleviating excess Glu release during Cd shock. RIL mitigate Glu outburst in duckweed during Cd stress by a decline in Glu in roots. The Cd2+ influx was repressed by RIL addition with Cd shock. Finally, differentially expressed genes (DEGs) of duckweed under Cd stress with RIL have been investigated. 2141 genes were substantially up-regulated and 3282 genes were substantially down-regulated with RIL addition. RIL down-regulates the genes related to the Glu synthesis, and genes related to DNA repair have been up-regulated with RIL treatment under Cd stress. These results provide new insights into the possibility of RIL to reduce Cd accumulation and increase Cd tolerance in duckweed, and lay the foundation for decreasing Cd accumulation in crops. [Display omitted] • Cd stimulates Glu signal responses from root to above, showed by iGluSnFR transgenic duckweed. • Riluzole (RIL) addition enhanced Cd tolerance in duckweed. • RIL declines Cd accumulation by blocking Glu release during Cd stress, and down-regulates the genes related to the Glu synthesis. • Genes related to DNA repair have been up-regulated by RIL under Cd stress. [ABSTRACT FROM AUTHOR]

Physiological, biochemical and electron microscopy analyses were used to investigate the photosynthetic performance of flag leaves in rice white stripe mutant 6001 during the senescence process. Results showed that the chlorophyll content at the heading and milk-ripe stages in rice mutant 6001 were about 34.78% and 3.00% less than those in wild type 6028, respectively. However, the chlorophyll content at the fully-ripe stage in rice mutant 6001 was higher than that in wild type 6028. At the heading stage, the net photosynthetic rate ( P n ) in rice mutant 6001 was lower than that in wild type 6028. Rice mutant 6001 also exhibited a significantly slower decrease rate of P n than wild type 6028 during the senescence progress, especially at the later stage. Furthermore, Ca 2+ -ATPase, Mg 2+ -ATPase and photophosphorylation activities exhibited the similar trends as the P n . During the senescence process, the 68 kDa polypeptide concentrations in the thylakoid membrane proteins exhibited a significant change, which was one of the critical factors that contributed to the observed change in photosynthesis. We also observed that the chloroplasts of rice mutant 6001 exhibited higher integrity than those of wild type 6028, and the chloroplast membrane of rice mutant 6001 disintegrated more slow during the senescence process. In general, rice mutant 6001 had a relatively slower senescence rate than wild type 6028, and exhibited anti-senescence properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] Desalination brine discharges can cause increments and fluctuations of salinity. [•] We detect some negative effects of a brine discharge on Cymodocea nodosa. [•] It was detected a leaf growth decrease and an increase in shoot mortality. [•] An increase in the % of horizontal respect to vertical shoots was also detected. [•] Not only salinity changes, but also slightly higher temperatures can cause these negative effects. [ABSTRACT FROM AUTHOR]

Bitter gourd or bitter melon (Momordica charantia L.) is an unknown in Poland vegetable of the Chinese origin commonly used in Eastern Asia to feed and cure diabetic people. In the years 2012-2013, the investigations were carried out on preparing its transplants and growing it in Poland using two ways of cultivation: with the supporting sticks or lying directly on the ground. The received transplants and then plants were analyzed for their selected morphological characters. The collected fruits were analyzed for their ash, dry weight, total protein, fats and carbohydrates, Ca, Mg, K, Na, Fe, Mn, Zn and Cu contents. The best transplants were those of 3 leaves, 7 cm high with the biggest leaf's width over 5 cm. The growing the species with the sticks lowered their total fruit yield but increased the weight of an individual fruit. When planting the transplants before June lst, germinating seeds were produced. When planting after that time, fruit were set but seeds were not ripened. The fruits from plants grown with the sticks had lower dry matter and Mn contents than the ones lying on the ground. The way of cultivation of the plants had no effect on all other analyzed chemical elements and characters. [ABSTRACT FROM AUTHOR]

Highlights: [•] Seedlings of all three tree species were stunted in the forest understorey. [•] In gaps, herbivores reduced most the height and leaf growth of M. bisulcata. [•] Without insect herbivores, M. bisulcata grew taller than the other two species. [•] Leaves of M. bisulcata were most damaged, and they died faster in the understorey. [•] Herbivores function to limit sapling recruitment of M. bisulcata in this community. [Copyright &y& Elsevier]

The article presents a study on the effect of the air pollutant tropospheric ozone on morphological characteristics of Nicotiana tabacum, Phaseolus vulgaris and Petunia hybrida, which include leaf injury and flowers and stalks, in ambient air condition. One of the objectives of the study was to examine effect on flower and fruit creation of crops and ornamental plants during the growing season. Noted is the association between ozone and solar radiation.

Abstract: Little is known of the effect of selective plant defoliation at different intensities and frequencies in altering weed-forage dynamics in pasture. We conducted a field experiment to quantify Cirsium arvense responses to varying defoliation regimes of neighboring forage implemented for 2 years under high or low fertility conditions. Defoliation regimes were based on common grazing systems, and included: (1) high intensity–high frequency (HIHF) defoliation simulating continuous grazing, (2) high intensity–low frequency (HILF), (3) low intensity–high frequency (LIHF), and (4) deferred (DEF) defoliation to peak growth in late summer. All vegetation except C. arvense was defoliated during the growing season to examine weed responses to changes in neighboring forage abundance. Year-end C. arvense biomass at the end of the study was greatest in the HIHF treatment and lowest in the DEF, with the LIHF and HILF treatments intermediate in response. The HILF treatment also provided improved suppression of C. arvense biomass relative to the LIHF, although this response was inconsistent among sites. Trends in C. arvense shoot densities among defoliation treatments were similar to those for biomass. While weed abundance was lower in the absence of fertilization, rankings among defoliation treatments remained the same. Notably, trends in forage biomass among defoliation regimes followed a pattern opposite that of C. arvense, and are implicated in observed weed decreases. Our results indicate that defoliation regimes enhancing forage growth and biomass, particularly a DEF or HILF regime, reduce C. arvense the most. Grazing systems that employ these defoliation regimes are therefore likely to optimize the interspecific competitive suppression of C. arvense. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effects of iron deficiency and cadmium (Cd) on the growth and performance of poplar. The study involved the comparison of the symptoms of Cd stress and Cd-induced iron deficiency. It has been found out that Cd-induced strong iron deficiency influences the development of the photosynthetic apparatus under Cd stress while the presence of Cd affects leaf growth.

The article discusses a study which investigated the physiological responses of Arabidopsis thaliana to the interaction of iron (Fe) deficiency and nitrogen (N) form. The study utilized 30 three-day-old seedlings that were treated for seven days. Leaf growth and chlorophyll content were highest in NO3-fed seedlings. Meanwhile, root acidification capacity and iron-chelate reductase (FCR) activity were found to be dependent on N form. Study authors concluded that N form and Fe level induce antioxidant responses in rosette leaves.

Copyright of Neotropical Biology & Conservation is the property of Pensoft Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: To address the pressing need to evaluate how conifer plantations can serve biodiversity functions in addition to other economic and social roles they play, we assessed the diversity of broad-leaf seedlings and saplings in Cryptomeria japonica plantations in Ogawa, Ibaraki Prefecture, Japan at increasing distances (0–1000m) from old growth natural forest edge. For saplings, there was no overall significant trend in the frequency, species richness, and Shannon index with respect to distance. Seedlings on the other hand showed a decrease in frequency and species richness with increasing distance from the old growth forest, implying that should recruitment limitation occur in the plantations, it will be stronger at the seed-to-seedling transition than at the seedling-to-sapling transition. Assigning species into groups based on functional traits that are associated with recruitment and regeneration was more revealing. Relative frequency of species that are moderately shade-tolerant, are shrubs, have small seeds, and are frugivore-dispersed increased in the plantations. In comparison, species that are tall trees, have large seeds and are gravity-dispersed decreased in the plantations. Multi-trait analysis showed that propagule size was the trait that could best explain the difference in the distribution of broad-leaf species in the plantations. Based on our results, we suggest to policy-makers that plantation sizes be kept to within a few hundred meters wide, and should ideally be within dispersal distance of species from natural forests that could potentially be seed sources of broad-leaf species. Otherwise, steps must be taken to drive succession such that potentially recruitment-limited species may be able to overcome barriers to regeneration. [Copyright &y& Elsevier]

Abstract: The ecological consequences of climate change for large tropical forests such as the Amazon are likely to be profound. Amazonian forests strongly influence regional and global climates and therefore any changes in forest structure, such as deforestation or die-back, may create positive feedback on externally forced climate change. Monitoring, modelling and managing the impacts of anthropogenic climate change on forest dynamics is therefore an important objective of forest researchers, and one that requires long-term data on changes at the level of community, populations and phenotypes. In this paper we provide the most comprehensive study yet on the seasonal dynamics of various leaf traits: leaf area index (LAI), leaf mortality (LM), leaf biomass (LB), leaf growth rate (LG), and leaf residence time (TR) from 50 experimental plots in a forest site at Belterra, Pará State, Brazil. From this study we estimate annual mean leaf area index (LAI) to be 5.07m2 m−2 and annual mean leaf dry biomass to be 0.621kgm−2. The typical leaf grew at 0.049kgm−2 month−1 and remained on the tree for 12.7 months. We compare these results to other similar studies and critically discuss the factors driving leaf demographics in Amazonia. [Copyright &y& Elsevier]

Abstract: The study aimed to explore if changes in crown defoliation and stem growth of Scots pines (Pinus sylvestris L.) could be related to changes in ambient ozone (O3) concentration in central Europe. To meet this objective the study was performed in 3 Lithuanian national parks, close to the ICP integrated monitoring stations from which data on meteorology and pollution were provided. Contribution of peak O3 concentrations to the integrated impact of acidifying compounds and meteorological parameters on pine stem growth was found to be more significant than its contribution to the integrated impact of acidifying compounds and meteorological parameters on pine defoliation. Findings of the study provide statistical evidence that peak concentrations of ambient O3 can have a negative impact on pine tree crown defoliation and stem growth reduction under field conditions in central and northeastern Europe where the AOT40 values for forests are commonly below their phytotoxic levels. [Copyright &y& Elsevier]

Abstract: The seasonal changes in throughfall (TF) and stemflow (SF) chemistry and the canopy interactions of K+ and N compounds were studied in a Japanese cedar forest near the Sea of Japan. The fluxes of most ions, including non-sea-salt SO4 2−, from TF, SF, and rainfall showed distinct seasonal trends, increasing from autumn to winter, owing to the seasonal west wind, while the fluxes of NH4 + and K+ ions from TF+SF might have a large effect of canopy interactions. The contact angle (CA) of water droplets on leaves decreased with leaf aging, suggesting that surface wettability increases with leaf age. The K+ concentration in TF was negatively correlated with the CA of 1-year-old leaves, while the NH4 + concentration was positively correlated with the CA. The net fluxes of NH4 + and NO3 − from TF were positively correlated with the CA. The increase in wettability may accelerate leaching of K+ or uptake of NH4 +. [Copyright &y& Elsevier]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: In eucalypts the reduction in CO2 assimilation and total leaf area at low phosphorus (P) supply is not associated with lower leaf total P concentrations. We tested the hypothesis that the leaf concentration of inorganic phosphorus ([Pi]) may be a better indicator of P nutrition status in Eucalyptus grandis W. Hill ex Maiden by growing seedlings in P deficient soil supplemented with P supplies ranging from 3 to1000mgkg−1. Height, biomass accumulation, gas exchange, chlorophyll fluorescence and concentrations of total P ([Pt]), organic P ([Po]) and [Pi] of the last fully expanded leaves were measured when harvested at 19 weeks. All parameters of growth increased with larger applications of soil P with most becoming saturated at additions of 500mgPkg−1 soil. Soil P supply had larger effects on biomass and canopy leaf area, by both increased in leaf initiation and expansion, than on CO2 assimilation (A). Leaf [Pt] and [Po] concentrations were largely invariant to soil P supply and were not correlated with any of the measured growth and photosynthetic parameters. By contrast, leaf [Pi] increased from 171 to 398mgkg−1 with increasing soil P supply. Furthermore, number of leaves, total leaf area and seedling biomass increased exponentially with leaf [Pi], while individual leaf area and A increased linearly with leaf [Pi], and quantum yield of photosystem II similarly increased, and non-photochemical quenching decreased, with increasing leaf [Pi]. The response of A to internal CO2 concentration (C i) indicated that at lower P supplies A became increasingly restricted by limitations associated with Rubisco and RuBP regeneration. Stomatal limitation may in part be masking the full effect of P supply on A as C i declined with either increasing soil P or leaf [Pi] supply. We conclude that leaf [Pi] was a potentially better indicator than [Pt] or [Po] for correlating the effects of soil P supply on growth and photosynthesis of E. grandis. Furthermore, as A achieved at saturating C a increased with increasing P supply leaf [Pi], these findings suggest that a greatly increased rate of canopy assimilation could be achieved at higher P supply in response to the expected increase in global CO2 levels. [Copyright &y& Elsevier]

Summary: To test the isolated and combined effects of drought and defoliation on biomass partitioning and water relations, four-year-old saplings of Quercus robur L. and Q. petraea (Matt.) Liebl. were investigated under controlled conditions. It was hypothesized that defoliation leads to a reduction of late wood and that, as a consequence, subsequent drought stress will more rapidly lead to desiccation damage due to the loss of reserves in water transport capacity. Alternatively, defoliation could have a negative effect on water relations via a growth reduction of the fine-root system, thereby diminishing the trees capacity for water uptake. Four treatments were applied to each species: (1) control C, (2) defoliation in two consecutive years De, (3) drought stress in the second year Dr, (4) a combination of (2) and (3) DeDr. Drought-stressed trees showed a decrease of predawn and mid-day water potentials and of maximum stomatal conductance (gsm). Defoliated trees exhibited a higher gsm compared to non-defoliated trees even under drought-stress conditions. At the end of the drought period the daily sum of transpiration per unit leaf area (Ed) was only reduced in Dr, but not in DeDr trees, and was even increased in De trees of Q. robur. Fine-root mass, leaf mass, leaf area and specific leaf area decreased due to defoliation. Drought stress also led to a reduction of leaf mass in Q. petraea as well as to reduced leaf/fine-root ratio (Dr and DeDr trees) in both species. Although a reduction of late wood was found in DeDr trees of Q. robur and in the interannual comparison of De and DeDr twigs of Q. petraea, no restrictions of transpiration or hydraulic conductance could be observed in both species. Therefore, this finding supports the alternative hypothesis, i.e. a possible impairment of the trees water relation caused by a reduction of the fine-root biomass due to defoliation. A combination of both stress factors impairs the morphological acclimatization to drought, i.e. an increased formation of fine-root biomass, and, partly, the physiological avoidance of dehydration, i.e. a reduction in stomatal conductance. Therefore, it is concluded that, in contrast to an isolated occurence of the stressors, their combined action depending on the time of occurrence of the stressors will ultimately result in tree damage due to desiccation. Unter kontrollierten Bedingungen wurden die Auswirkungen von Trockenheit und Entlaubung einzeln und in Kombination auf die Biomassenpartitionierung und den Wasserhaushalt vierjähriger Pflanzen von Quercus robur L. and Q. petraea (Matt.) Liebl. untersucht. Es wurde angenommen, dass Entlaubung in einer Reduktion des Spätholzes resultiert, und infolgedessen anschließender Trockenstress schneller zu Trocknisschäden aufgrund fehlender Wassertransportreserven führt. Alternativ kann Entlaubung einen negativen Effekt auf den Wasserhaushalt des Baumes über eine Reduktion des Feinwurzelsystems ausüben, was zu einer Verringerung der Wasseraufnahmekapazität führt. Bei beiden Arten wurden vier Varianten untersucht: (1) Kontrolle C, (2) Entlaubung in zwei aufeinanderfolgenden Jahren De, (3) Trockenstress im zweiten Jahr Dr, (4) eine Kombination aus (2) und (3) DeDr. Trockengestresste Bäume zeigten eine Abnahme der Predawn- und nachmittäglichen Wasserpotentiale als auch der maximalen stomatären Leitfähigkeit (gsm). Entlaubte Bäume wiesen auch unter Trockenstressbedingungen eine höhere gsm auf als nicht-entlaubte Bäume. Gegen Ende der Trockenperiode war die Tagestranspirationssumme pro Blattflächeneinheit (Ed) nur bei Dr, nicht aber bei DeDr, reduziert und bei De von Q. robur sogar erhöht. Feinwurzelmasse, Blattbiomasse, Blattfläche und die spezifische Blattfläche nahmen bei entlaubten Bäumen ab. Trockenstress führte zudem zu einer Reduktion der Blattfläche bei Q. petraea als auch zu einem reduzierten Blatt/Feinwurzelverhältnis (De und DeDr) bei beiden Arten. Obwohl DeDr-Bäume von Q. robur eine Reduktion des Spätholzes aufwiesen und dies auch in dem Vergleich zwischen den Jahren bei De und DeDr bei Q. petraea der Fall war, wurden keine signifikanten Beeinträchtigungen der Transpiration und der hydraulischen Leitfähigkeit festgestellt. Dies unterstützt die Alternativhypothese, d.h. eine mögliche Beeinträchtigung des Wasserhaushaltes durch eine entlaubungsbedingte Reduktion der Feinwurzelbiomasse. Eine Kombination beider Faktoren beeinträchtigt die morphologische Akklimatisation an Trockenheit, die normalerweise durch eine Erhöhung der Feinwurzelbiomasse erreicht wird, und zum Teil auch die physiologische Verhinderung von Wasserverlusten, die sonst aus einer reduzierten Stomataöffnungsweite resultiert. Es wird geschlossen, dass, im Gegensatz zum isolierten Auftreten der Stressoren, eine Kombination beider Faktoren, je nach dem Zeitpunkt ihres Auftretens, letztendlich zu Trocknisschäden führen wird. [Copyright &y& Elsevier]

Arsenite [As(III)] toxicity causes impeded growth, inadequate productivity of plants and toxicity through the food chain. Using various chemical residues for priming is one of the approaches in conferring arsenic tolerance in crops. We investigated the mechanism of abscisic acid (ABA)-induced As(III) tolerance in rice genotypes (cv. Swarna and Swarna Sub1) pretreated with 10 μM of ABA for 24 h and transferred into 0, 25 and 50 μM arsenic for 10 days. Plants showed a dose-dependent bioaccumulation of As(III), oxidative stress indicators like superoxide, hydrogen peroxide, thiobarbituric acid reactive substances and the activity of lipoxygenase. As(III) had disrupted cellular redox that reflecting growth indices like net assimilation rate, relative growth rate, specific leaf weight, leaf mass ratio, relative water content, proline, delta-1-pyrroline-5-carboxylate synthetase and electrolyte leakage. ABA priming was more protective in cv. Swarna Sub1 than Swarna for retrieval of total glutathione pool, non-protein thiols, cysteine, phytochelatin and glutathione reductase. Phosphate metabolisms were significantly curtailed irrespective of genotypes where ABA had moderated phosphate uptake and its metabolizing enzymes like acid phosphatase, alkaline phosphatase and H+/ATPase. Rice seedlings had regulated antioxidative potential with the varied polymorphic expression of those enzymes markedly with antioxidative enzymes. The results have given the possible cellular and physiological traits those may interact with ABA priming in the establishment of plant tolerance with As(III) over accumulation and, thereby, its amelioration for oxidative damages. Finally, cv. Swarna Sub1 was identified as a rice genotype as a candidate for breeding program for sustainability against As(III) stress with cellular and physiological traits serving better for selection pressure. [Display omitted] • As(III) toxicity is more aligned to P depletion through plasma membrane. • ABA can stimulate H+/ATPase in exchange of P uptake. • GSH metabolism is an important cellular trait in As(III) tolerance. • ABA can support compatible solute development in sub1A QTL against As(III) stress. • Genetic polymorphism is attributed for better tolerance under As(III) accumulation. As(III) toxicity causes oxidative stress and decline growth and metabolism of rice plant. However, priming with ABA stimulates H+/ATPase in exchange of phosphate uptake, enhances antioxidant defense and improves plant metabolism. [ABSTRACT FROM AUTHOR]

Glyphosate and microplastics are widely found in marine, terrestrial, and freshwater environments due to their globally widespread application. Further, they have proved to have specific ecotoxicity effects on aquatic plants. However, few studies have focused on the effects of small plastic particles and glyphosate, or especially, their combined effect on vascular plants in freshwater ecosystems. This study aimed to conduct a simulated greenhouse experiment to investigate the ecotoxicity of polystyrene microplastics and glyphosate on the floating plant Salvinia cucullata by exposure to fluorescent polystyrene microplastics (1 μm; concentration, 3, 15, and 75 mg/L), glyphosate (5, 25, and 50 mg/L), and a mixture of the two (3 + 5, 15 + 25, and 75 + 50 mg/L) for seven days. Glyphosate significantly reduced the relative growth rate, photosynthetic capacity, and root activity of S. cucullata. Polystyrene microplastics did not significantly influence photosynthesis or leaf morphological characteristics but they significantly reduced relative growth rate and root activity in S. cucullata , indicating that the effects of microplastics on aquatic plants are potentially associated with different organs exposed to pollution. Polystyrene microplastics and glyphosate activated the plant antioxidant defense systems by increasing antioxidative enzyme activities including, superoxide dismutase, ascorbate peroxidase, and catalase to cope with oxidative stress. Synergistic effects (only observed in percent leaf yellowing) were observed when S. cucullata was exposed to a high concentrations (≥15 + 25 mg/L) of glyphosate and microplastics. Our results indicate that pervasive microplastics and herbicide contamination in freshwater may potentially affect the growth of aquatic plants. [Display omitted] • Polystyrene microplastics and glyphosate had ecotoxicity effects on S. cucullata. • Polystyrene microplastics and glyphosate caused physical damage to S. cucullata. • Glyphosate and microplastics caused oxidative stress accumulation in S. cucullata. • Microplastics and glyphosate caused single and synergistic effects on leaf growth. [ABSTRACT FROM AUTHOR]

Examines the impact of intensive silvicultural treatments on environmental conditions, leaf level morphology and physiology, growth of planted eastern white pine saplings. Influence of silvicultural treatments and the presence of competing vegetation on the relationships between leaf nitrogen, leaf morphology and leaf level photosynthetic capacity of saplings.

The effect of methanolic and aqueous extracts of bilberry leaves on the growth of Aspergillus flavus and on its ability to synthesize aflatoxins was studied. Both extracts could inhibit aflatoxins' biosynthesis by A. flavus grown in either a rich or minimal media. Aqueous extracts were more efficient, at totally inhibiting aflatoxins biosynthesis at ~2.8 and 2.2 mg/ml for aflatoxins B1 and B2, respectively, in rich medium, whereas in minimal medium the respective values were 625 and 313 μg/ml. Methanolic extracts were less efficient, as they did not completely inhibit the biosynthesis even at higher concentrations of the extract. The results suggested that bilberry leaves may contain substances that can be used as natural food additives. • Either methanolic or aqueous bilberry leaf extracts do not affect Aspergillus flavus growth. • Both methanolic and aqueous extracts could inhibit aflatoxin production in rich and minimal medium. • Aqueous extracts had a stronger anti -aflatoxigenic effect than the methanolic ones. • Half maximal inhibitory concentration (IC 50) for aflatoxin biosynthesis was determined. [ABSTRACT FROM AUTHOR]

• A toposequence approach is used to examine intraspecific variability of larch leaf traits and tree growth. • Leaf traits and tree growth differ with site conditions along the toposequence. • Correlations between leaf economics and hydraulics traits extend leaf economics spectrum intraspecially. • Leaf economics traits better predict tree growth than leaf hydraulics traits. Intraspecific variations in leaf traits and tree growth along environmental gradients are crucial for survival and distribution of the tree species, but they are substantially less quantified than interspecific counterparts. Here, we examined the intraspecific variations in leaf hydraulics and economics traits and growth of Larix gmelinii Rupr. – the predominant tree species in the Eurasian boreal forests with a toposequence approach. The toposequence included three replicated 1000-m transects of the larch plantation (31-year-old), each of which consisted of three plots located at the toe-, mid-, and top-slope, respectively. We found that the leaf hydraulics traits showed a "high-low-high" pattern along the toposequence, while the leaf economics traits, total biomass (TB) and TB increment (TBI) displayed an opposite trend, largely consistent with changes in site conditions especially soil nitrogen concentration. This suggests that the intraspecific variation in tree growth is coupled with leaf traits and site conditions. Leaf mass per area explained 21.9% of the variability in TB, while and the ability of drought tolerance explained 22.5% of that in TBI; and the interactions of hydraulic and economic variables explained additional 23.1–26.2% of that in TB or TBI. This result indicates that leaf traits interactively affect TB and TBI, but the hydraulics and economics play major roles in the short-term growth rate and relatively long-term biomass stock, respectively. Together, our findings demonstrate that the larch trees acclimate the leaf traits and growth/biomass accumulation to site conditions, and provide insights into the mechanistic understanding of forest production. [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O 3) impairs physiological processes of plants while nitrogen (N) deposition may cause imbalances in soil N and other nutrients such as phosphorus (P) suggesting an increase of P demand for plants. However, the combined effect of O 3 , soil N and P on isoprene emission from leaves has never been tested. We therefore examined isoprene emission in leaves of Oxford poplar clone exposed to O 3 (ambient, AA [35.0 nmol mol−1 as daily mean]; 1.5 × AA; 2.0 × AA), soil N (0 and 80 kg N ha−1) and soil P (0, 40 and 80 kg P ha−1) in July and September in a Free-Air Controlled Exposure (FACE) facility. We also investigated the response of isoprene emission to foliar N, P and abscisic acid (ABA) contents in September because the 2-C-methylerythritol-5-phosphate (MEP) pathway of isoprenoid biosynthesis produces ABA. We found that O 3 increased isoprene emission in July, which was associated to increased dark respiration, suggesting an activation of metabolism against O 3 stress as an initial response. However, O 3 decreased isoprene emission in September which was associated to reduced net photosynthesis. In September, isoprene emission was positively correlated with leaf N content and negatively correlated with leaf P content in AA. However, no response of isoprene emission to foliar N and P was found in elevated O 3 , suggesting that the isoprene responses to foliar N and P depended on the O 3 exposure levels. Isoprene emission rate in 1.5 × AA and 2.0 × AA increased with increasing leaf ABA content, indicating accelerated senescence of injured leaves to favor new leaf growth when high O 3 and nutritional availability in the soil were combined. Even though foliar N and P usually act as a proxy for isoprene emission rate, the impact of recent abiotic factors such as O 3 should be always considered for modeling isoprene emission under climate change. Image 1 • We examined the interaction of O 3 , N and P on isoprene emission (IE) in poplar. • O 3 increased IE in July, but decreased it in September. • IE was increased by N supply but decreased by P supply under low O 3 environment. • IE, however, did not depend on foliar N and P in elevated O 3 in September. • IE in elevated O 3 positively correlated with leaf ABA content. [ABSTRACT FROM AUTHOR]

Coastal ecosystems, and especially estuaries, are subject to environmental fluctuations that can be amplified by anthropogenic changes. Under a future scenario of global warming, temperature and salinity are likely to be altered and the persistence of macrophyte-dominated ecosystems can be compromised, particularly native or local seagrass communities. This study examined the response of the local seagrass Halophila ovalis to the joint effect of a short-term salinity increase and a transient temperature stress, through two mesocosm experiments. Warming caused a decline in F v /F m , TNC content in leaves and plant growth, and increased dark respiration, revealing clear detrimental symptoms of heat stress on plant metabolism and performance. Salinity increase in isolation favoured ramet survival. However, in combination with warming, salinity had a positive effect on Gross P max. This suggests that increased salinities might dampen the negative effects of high temperatures, buffering, to some extent, the impact of global warming in temperate estuaries. • High temperature adversely affects H. ovalis at biochemical and physiological level. • Increased salinity has no negative effects on Halophila ovalis plant performance. • The simultaneous occurrence of warming and high salinity shows interactive effects. • High salinities seem to buffer the impacts of transient warming. [ABSTRACT FROM AUTHOR]

• The remote sensing process was an useful tool for coffee rust monitoring. • Center pivot irrigation system determined high rust incidence in the coffee field. • Coffee rust can be detected in the host using visible, infrared surface reflectance values and brightness temperature. Coffee rust (Hemileia vastatrix Berk. & Br.) is one of the most prominent diseases in coffee (Coffea arabica L.) and causes serious damage to the crop. The pathogen incubation period may be long for about 30 days and 10% incidence of rust may result in 3 times more disease few days after the signals of rust appear in the leaves, even in the absence of new infections. The objective of this study was to evaluate the applicability of coffee crop monitoring under different irrigation systems by orbital radiometry, exploring the spectral signature and spectral, spatial and temporal pattern of rust incidence in the coffee field. The study was carried out in four areas of coffee plantations in Carmo do Rio Claro, Minas Geris, Brazil, between August 2012 and December 2014, under self-propelled, drip, center pivot irrigation systems and rainfed system. Fifteen Landsat-7/ETM + and Landsat-8/OLI-TIRS images were used, trying to establish a better sequence of images between in situ data of rust incidence in the coffee leaves and coffee leaf growth evaluated by sample meshes in the field along the time. Space-time disease incidence distribution maps, Pearson correlation and reflectance spectral signatures were used to evaluate coffee rust progress in the different irrigation fields. The highest coffee rust incidence occurred in August and corresponded to the values of lower NIR reflectance for all evaluated areas, independently of the irrigation management system. In the visible, SWIR-1 and SWIR-2 spectral regions, there were higher reflectance values in the rainfed area when compared to irrigated areas in rainy periods. There was a greater spectral and temporal variation of rust in the center pivot irrigation system when compared to the other irrigation management systems, presenting high values ​​of average incidence of rust above 30% in the periods close to the harvest period, from June to August 2013 and 2014. The high incidence of rust associated with coffee fruit harvest probably led to a reduction in plant leaf growth in center pivot and rainfed fields. There was a negative correlation between near infrared and rust in the self-propelled and center pivot management systems. High coffee rust incidence values mainly in center pivot and rainfed coffee fields determined reduction in the average reflectance of NIR and green and increase reflectance in red, SWIR-1 and SWIR-2 when compared to periods with lower rust in the coffee fields. [ABSTRACT FROM AUTHOR]

Information on silver nanoparticle (AgNP) phytotoxicity on seagrasses is provided for the first time. Toxic effects of environmentally relevant AgNP concentrations on Halophila stipulacea were assessed to identify sensitive biomarkers, to determine threshold effect concentrations and to evaluate potential risks. Potential alterations in the cytoskeleton, endoplasmic reticulum, cell ultrastructure and viability, oxidative stress parameters and elongation in H. stipulacea leaves exposed to AgNP concentrations ranging from 0.0002 to 0.2 mg L−1 for 8 days were examined. The first signs of actin filament (AF) response in differentiating cells, exhibiting disorientation and slight bundling, were observed on the 4th day at 0.0002 mg L−1, while at the end of the experiment and at the higher concentrations, AFs were extremely bundled. Endoplasmic reticulum was affected in meristematic and differentiating cells; massive aggregations and loss of the "grainy" structure were observed, initially on the 6th day at 0.002 mg L−1. Effects on microtubules were detected on the last day at 0.2 mg L−1. An increase in H 2 O 2 levels on the 4th and/or 6th day even at 0.0002 mg L−1 was followed by a decrease on, or up to the last day. On the 6th day at the lowest concentration, elevated malondialdehyde content, and superoxide dismutase and peroxidase activity were detected, indicating oxidative damage and antioxidant defense mechanism activation. Dead epidermal cells mainly occurred at 0.02 and 0.2 mg L−1, while no dead vein cells were detected. A significant inhibition in leaf elongation was observed only at 0.2 mg L−1. Therefore, AF disturbance in differentiating leaf cells, being a susceptible response parameter, could be regarded as an early warning indicator of risk posed by AgNPs to H. stipulacea meadows, while most of the remaining parameters examined also constitute useful biomarkers. The lowest observed effect concentration (0.0002 mg L−1), being within the range of environmentally relevant AgNPs concentrations, suggests the possibility of negative impacts of AgNPs on seagrass health. A risk quotient of 1.33 was calculated, indicating that AgNPs may pose a significant potential risk to the coastal environment. The data presented highlight the importance of future research to further investigate the seagrass-AgNP interactions, stress the need for a refinement of the environmental risk assessment of AgNPs and could be utilized for the design of biomonitoring programs for rational management of the coastal environment. • AgNPs at environmentally relevant concentrations cause toxic effects on seagrasses. • AgNPs induce oxidative stress and cell death in Halophila stipulacea leaves. • AgNPs impair cytoskeleton, endoplasmic reticulum and leaf growth in H. stipulacea. • Actin filament damage and H 2 O 2 level are early warning indicators of AgNP stress. • AgNPs may pose a significant potential risk to the coastal environment. [ABSTRACT FROM AUTHOR]