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ABSTRACT Extensive foliar shedding in monoculture soybeans post‐anthesis negatively impacts yield, whereas relay strip intercropping prolongs leaf area duration, enhancing productivity. However, little is known about the causes of leaf shedding in monoculture and its impact on physiological functions and plasticity of source and sink organs, we conducted a 4‐year field experiment and leaf‐removal simulations in relay intercropped soybeans. Results revealed that monoculture soybeans experienced severe self‐shading and defoliation, while relay intercropping maintained better light conditions, supporting higher leaf area, nodule numbers, and carbon allocation. Increasing leaf removal initially increased leaf area but eventually reduced it. Extensive leaf‐removal reduced Rubisco and sucrose phosphate synthase (SPS) activity, as well as sucrose, malate, ATP, and energy charge (EC) in nodules, revealing a trade‐off between leaf growth and nodule development. Moderate leaf‐removal (L30), however, balanced compensation and consumption, increasing total non‐structural carbohydrates (TNC) in roots and N and ureide in leaves and pods. Network analysis showed that L30 improved the synergies of functional traits in leaves and nodules, ultimately benefiting overall plant growth and nutrient accumulation in pods. This study elucidates a mechanism of foliar shedding and highlights how relay strip intercropping optimizes source‐sink coordination to enhance photosynthesis and nitrogen fixation. [ABSTRACT FROM AUTHOR]

Plant wearable sensors have shown exceptional promise in continuously monitoring plant health. However, the potential adverse effects of these sensors on plant growth remain unclear. This study systematically quantifies wearable sensors' interference with plant growth using two ornamental species, Peperomia tetraphylla and Epipremnum aureum. We evaluated the impacts of four common disturbances—mechanical pressure, hindrance of gas exchange, hindrance of light acquisition, and mechanical constraint—on leaf growth. Our results indicated that the combination of light hindrance and mechanical constraint demonstrated the most significant interference. When the sensor weight was no greater than 0.6 g and the coverage was no greater than 5% of the leaf area, these four disturbances resulted in slight impacts on leaf growth. Additionally, we fabricated a minimally interfering wearable sensor capable of measuring the air temperature of the microclimate of the plant while maintaining plant growth. This research provides valuable insights into optimizing plant wearable sensors, balancing functionality with minimal plant interference. [ABSTRACT FROM AUTHOR]

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The pertinent study assessed the different photosynthetic activity parameters in spring soft wheat (Triticum aestivum L.) genotypes based on diverse mineral nutrition levels. The dynamics of leaf area growth, photosynthetic potential, and net crop productivity at various developmental stages reached analysis. The determined average correlation between yield and flag leaf area for three research backgrounds showed that not all wheat genotypes responded equally to the mineral fertilizer due to their varied biological characteristics and genetic backgrounds. It was also evident that enhancement in leaf area and photosynthetic parameters appeared in wheat genotypes when applied with complete fertilizer doses. For instance, the following rates emerged for the maximum flag leaf area (12 300 m2 /ha), the total leaf area (17 700 m2 /ha), photosynthetic potential (0.960 million m2 /day), and the net photosynthesis productivity (6.7 g/m2 per day), with the average grain yield on this background was 3.3 t/ha. The increase in the number of nodal roots of spring soft wheat genotypes mainly responded to the different mineral nutrition levels. In the context of a 0.5 calculated dose of mineral fertilizer, seven out of nine wheat lines had 22% more nodal roots, and the utmost calculated dose of mineral fertilizer was 24% more than the control treatment (unfertilized background), which was crucial for increasing the productivity considerably. [ABSTRACT FROM AUTHOR]

The ability to balance the allocation of resources between growth and reproduction as a response to stress factors, can be an advantage for plants in disturbed environments. Invasive alien plants (IAPs) often show high levels of phenotypic variability in resource allocation, a key trait that plays a crucial role in their success to invade new areas. Control management for IAPs must consider this capacity in the development of effective strategies. In this study, we performed continuous measures of leaf growth and reproductive traits of Cortaderia selloana, an IAP of global concern, and applied generalised linear models (GLMs) to evaluate trade‐offs between vegetative growth, leaf composition and reproductive success at different cutting moments. Cutting moment, but not flowering, affected the length of the vegetative growth period (VGP) and average growth rate (AGR), and the interaction with flowering affected AGR and final leaf length (vegetative growth total, VGT). Specific leaf area (SLA), leaf nitrogen (N) content and the isotopic value of δ13C were affected by cutting, and N was also affected by flowering and the interaction with cutting time. Silica also showed a negative correlation with leaf carbon (C) depicting a trade‐off between both structural components. Cortaderia selloana successfully adapted its leaf growth and composition to cutting moment, but this was also modulated by flowering. Moreover, the species is dioecious, and its response may differ between female and hermaphroditic plants. This suggests flexible trade‐offs in resource allocation, therefore the time for cutting must be precisely scheduled to suppress flowering. [ABSTRACT FROM AUTHOR]

Stress experienced during development in organisms with bilateral structures could result in developmental instability, which is expressed as subtle non‐directional deviations from perfect symmetry, known as fluctuating asymmetry (FA). As such, FA has been proposed, and extensively used, as a trait indicating stress for many organisms with bilateral structures and many types of stress. However, while this concept may apply to animals, the evidence for plants' main vegetative structures, that is, leaves, remains equivocal, and a comprehensive synthesis on this topic is still missing.We designed observational field and controlled greenhouse studies, combining different growth and leaf forms across multiple stress gradients, comprising 21 species and 80 populations. We measured FA as the difference between the left and right area of the leaf, an approach that accommodates diverse leaf forms. We used high‐precision, blind, single‐person measurements and tested for other forms of symmetry and the effect of leaf size. We further complemented our study with a systematic literature review of FA in plant leaves, compiling 51 studies comprising 72 species, 23 stress types and 131 unique entries (species × stress type).We consistently found no effect of stress on leaf FA in any of the studied species in both our field and experimental gradients. In the systematic literature review, only 39% of the unique entries showed the expected increase in FA with stress, 53% showed no effect, 9% showed an opposite trend of a decrease in FA with stress and 1% showed a unimodal relationship. Importantly, only 40% of all entries fulfilled the crucial step of controlling for a high‐precision measurement, and of these 49% reported the expected increase in FA with stress.Both the results of our observational and experimental approaches and the systematic literature review failed to support a clear relationship between stress and FA in plant leaves. These results clearly show that FA in plant leaves cannot be used as a reliable trait indicating stress during development. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

This study analyzed the leaf spectral properties and photosynthesis rates of greenhouse-grown bell pepper leaves according to the growth period and leaf position to investigate the changes in carbon assimilation function according to leaf aging. Photosynthesis, growth, transpiration, stomatal conductance, light transmittance, and light reflectance were measured. As the plants' growth progressed, the number of leaves, fresh weight, and dry weight increased, but the specific leaf area decreased, likely due to the increased distribution of assimilates to reproductive organs. The average photosynthesis rate, according to the measured dates, exhibited a high value despite a large standard error, which was likely influenced by measurement errors caused by external environmental factors. The reflectance and transmittance increased from the upper to the middle and bottom leaves, and the absorption ratio decreased in the same order. The green light spectrum (500–580 nm) had a lower absorption ratio than other spectra because the green coloration of the leaves increased the light reflectance of this spectrum. As the PPFD increased where the leaf was positioned higher, the photosynthesis rate, transpiration amount, and stomatal conductance also increased. The higher the leaf position, the higher the photosynthesis rate, the amount of transpiration, and the stomatal conductance. As the CO2 concentration increased, the photosynthesis rate increased, but the transpiration and stomatal conductance changed little, indicating that the gas exchange within leaves was hardly affected by CO2, but the light levels promoted photosynthesis. From the results of this study, the optical properties of the leaves indicate that they are consistent with Lambert–Beer's law, which implies that the length of the optical path is linearly proportional to the number of molecules in the absorption layer. We obtained the light saturation point and CO2 saturation point of bell peppers grown in a greenhouse and were able to determine the physiological changes in the leaves with increasing leaf age. Therefore, based on this information, it appears that a leaf removal model based on the productivity of bell pepper leaves could be developed. [ABSTRACT FROM AUTHOR]

Micronutrients are critical for the development of plants and play major role in enhancing both quantitative and qualitative crop yield. To examine the impact of foliar fertilization with micronutrients on various crop growth attributes, an experiment was conducted during kharif season of 2020 and 2021. Foliar spray with different combinations of zinc sulfate, ferrous sulfate, and manganese sulfate was done at 20 and 40 days after sowing. Increased plant height, leaf area index, leaf weight ratio, leaf area ratio, specific leaf weight, specific leaf area, crop growth rate, relative growth rate, and net assimilation rate were observed. Positive effect of foliar spray was observed in all parameters through all treatments. But, the overall maximum effect was observed in the treatment of foliar spray with T9 (0.2% FeSO4 +0.5% ZnSO4) followed by T7 (0.2% FeSO4 +0.2% ZnSO4) and T8 (0.5% FeSO4 and 0.2% ZnSO4). Given the positive effect of zinc, iron and manganese micronutrients on leaf and crop growth attributes, these treatments are suggested to be applied for the development of sweet corn. [ABSTRACT FROM AUTHOR]

Background: Growing evidence demonstrates that the synergistic interaction of far-red light with shorter wavelength lights could evidently improve the photosynthesis efficiency of multiple species. However, whether/how far-red light affects sink organs and consequently modulates the source‒sink relationships are largely unknown. Results: Here, equal intensities of white and far-red lights were added to natural light for grape plantlets to investigate the effects of far-red light supplementation on grapevine growth and carbon assimilate allocation, as well as to reveal the underlying mechanisms, through physiological and transcriptomic analysis. The results showed that additional far-red light increased stem length and carbohydrate contents in multiple organs and decreased leaf area, specific leaf weight and dry weight of leaves in comparison with their counterparts grown under white light. Compared to white light, the maximum net photosynthetic rate of the leaves was increased by 31.72% by far-red light supplementation, indicating that far-red light indeed elevated the photosynthesis efficiency of grapes. Transcriptome analysis revealed that leaves were most responsive to far-red light, followed by sink organs, including stems and roots. Genes related to light signaling and carbon metabolites were tightly correlated with variations in the aforementioned physiological traits. In particular, VvLHCB1 is involved in light harvesting and restoring the balance of photosystem I and photosystem II excitation, and VvCOP1 and VvPIF3, which regulate light signal transduction, were upregulated under far-red conditions. In addition, the transcript abundances of the sugar transporter-encoding genes VvSWEET1 and VvSWEET3 and the carbon metabolite-encoding genes VvG6PD, VvSUS7 and VvPGAM varied in line with the change in sugar content. Conclusions: This study showed that far-red light synergistically functioning with white light has a beneficial effect on grape photosystem activity and is able to differentially affect the growth of sink organs, providing evidence for the possible addition of far-red light to the wavelength range of photosynthetically active radiation (PAR). [ABSTRACT FROM AUTHOR]

Leaf traits are good indicators of ecosystem functioning and plant adaptations to environmental conditions. We examined whether leaf trait variability at species and community levels in Mediterranean woody vegetation is explained by growth form, regeneration mode, and vegetation type. We studied several plant communities across five vegetation types – semi‐closed forest, open forest, closed shrubland, open shrubland, and scrubland – in southwestern Anatolia, Türkiye. Using linear mixed models, community‐weighted trait means, and principal component analysis, we tested how much variability in three leaf traits (specific leaf area, leaf thickness, and leaf area) is accounted for species, growth form, regeneration mode, and vegetation type. Despite a large amount of leaf trait variability both within‐ and among‐species existed, functional groups still accounted for a significant part of this variability. Resprouters had higher SLA and leaf area and lower leaf thickness than non‐resprouters. However, further functional separation in regeneration mode, by considering the propagule‐persistence trait and the seed bank locality, explained leaf trait variability better than only resprouting ability. Although no consistent pattern was observed in three leaf traits in the growth form, we found evidence for the difference in SLA and leaf thickness between shrubs and large shrubs, and subshrubs had smaller leaves than other growth forms. Vegetation type also accounted for a substantial amount of leaf trait variability. Specifically, plant communities in closed habitats had larger leaf area than open ones, and those in scrublands had higher SLA, lower leaf thickness, and lower leaf area than other vegetation types. Climate and phylogeny had limited contribution to the results obtained, with the exception of a significant phylogenetic effect in explaining the differences in SLA between resprouters and non‐resprouters. Our results suggest that multiple drivers are responsible for shaping plant trait variability in Mediterranean plant communities, including growth form, regeneration mode, and vegetation type. [ABSTRACT FROM AUTHOR]

In vitro-propagated potato plantlets are commonly used in potato seed tuber production. Four experiments were carried out to identify how the duration of the last in vitro phase ('age') before planting of in vitro-produced plantlets affects the early growth and development ex vitro, assessed 10–14 days after planting. Experiments included varying ranges in age of the in vitro plantlets at planting (10–40, 15–45, 14–28 and 14–56 days old at the moment of planting in the respective experiments) and different cultivars. Because in vitro plantlet size increases with age, the first experiment studied interactions between age and planting method. Planting 'deep' (the upper four visible leaves above the ground) seemed more robust than planting 'shallow' (all nodes/leaves above ground except the lowest two), and in later experiments, only deep planting was applied. Across experiments, plants grown from younger in vitro plantlets had smaller leaf areas 10–14 days after planting than those from older in vitro plantlets. The increase in leaf area levelled off with increasing age of the in vitro plantlets used, especially when plantlets were older than c. 28 days. Larger leaf areas 10–14 days after planting were related to the older in vitro plantlets having higher absolute growth rates after planting and a larger above-ground leaf area at planting, even though four leaves were kept above ground in all treatments. Below ground, plants from older in vitro plantlets had more stem nodes, initiated stolons earlier after planting and initiated more stolons per plant. Tuber initiation rarely occurred within 14 days after planting, but was observed in some plants from 42- and especially 56-day-old in vitro plantlets of the very early cultivar Gloria and a single plant from 56-day-old in vitro plantlets of the mid-early cultivar Bintje. The data show that planting older in vitro plantlets can enhance early leaf area growth. Plants from older in vitro plantlets also more readily initiate stolons below ground and may be more advanced in the tuber formation process, especially when from early cultivars. [ABSTRACT FROM AUTHOR]

Environmental prejudices progressively lead to the ban of dwarfing molecules in agriculture, and alternatives are urgently required. Mechanical stimulation (MS) is a promising, eco-friendly, and economical technique, but some responses to mechanical stimulation vary from one plant species to another. Additionally, as more frequent and violent wind episodes are forecasted under global climate change, knowledge of plant responses to stimuli mimicking wind sways is decisive for agriculture. However, little is known about plant mechanosensitive responses after long-term, recurrent MS. Here, the effects of 3-week, recurrent, symmetrical bendings (1 or 12 per day) in Hydrangea macrophylla stems are examined. Bendings repressed internode elongation and leaf area development, whereas the diametrical growth of the basal internode is increased. Responses were dose-dependent, and no desensitization was observed during the 3 weeks of treatment. MS was almost as efficient as daminozide for plant dwarfing, and it improved stem robustness. Histological and molecular responses to MS were spatially monitored and were concordant with ongoing primary or secondary growth in the internodes. Our molecular data provide the first knowledge on the molecular paths controlled by mechanical loads in Hydrangea and revealed for the first time the involvement of XYP1 in thigmomorphogenetic responses. MS still had a transcriptional impact 48 h after the last bending session, promoting the expression of XYP1, FLA11, and CAD1 while repressing the expression of EXP3 and XTH33 homologs in accordance with xylogenesis, cell wall thickening, and lignin deposition in the xylem of basal internodes. In upper elongating internodes, repression of XYP1, CAD1, SAMS1, and CDC23 homologs is correlated with ongoing primary, even though stunted, growth. For producers, our findings highlight the potential of MS as a sustainable and economical option for controlling plant compactness in Hydrangea and show valuable reinforcement of stem strength. [ABSTRACT FROM AUTHOR]

SUMMARY: Plants grown under low magnesium (Mg) soils are highly susceptible to encountering light intensities that exceed the capacity of photosynthesis (A), leading to a depression of photosynthetic efficiency and eventually to photooxidation (i.e., leaf chlorosis). Yet, it remains unclear which processes play a key role in limiting the photosynthetic energy utilization of Mg‐deficient leaves, and whether the plasticity of A in acclimation to irradiance could have cross‐talk with Mg, hence accelerating or mitigating the photodamage. We investigated the light acclimation responses of rapeseed (Brassica napus) grown under low‐ and adequate‐Mg conditions. Magnesium deficiency considerably decreased rapeseed growth and leaf A, to a greater extent under high than under low light, which is associated with higher level of superoxide anion radical and more severe leaf chlorosis. This difference was mainly attributable to a greater depression in dark reaction under high light, with a higher Rubisco fallover and a more limited mesophyll conductance to CO2 (gm). Plants grown under high irradiance enhanced the content and activity of Rubisco and gm to optimally utilize more light energy absorbed. However, Mg deficiency could not fulfill the need to activate the higher level of Rubisco and Rubisco activase in leaves of high‐light‐grown plants, leading to lower Rubisco activation and carboxylation rate. Additionally, Mg‐deficient leaves under high light invested more carbon per leaf area to construct a compact leaf structure with smaller intercellular airspaces, lower surface area of chloroplast exposed to intercellular airspaces, and CO2 diffusion conductance through cytosol. These caused a more severe decrease in within‐leaf CO2 diffusion rate and substrate availability. Taken together, plant plasticity helps to improve photosynthetic energy utilization under high light but aggravates the photooxidative damage once the Mg nutrition becomes insufficient. Significance Statement: Plants grown under low Mg soils are highly susceptible to excessive light intensity, resulting in photooxidation and subsequent leaf chlorosis. The results indicated that plant plasticity, such as increasing Rubisco content and gm, helps to improve photosynthetic energy utilization under high light but aggravates the photooxidative damage once the Mg nutrition becomes insufficient. [ABSTRACT FROM AUTHOR]

Kentucky bluegrass (Poa pratensis L.) cultivars are diverse in their phenotype with a common classification system used to describe their growth habit but it is unclear why their growth differs. Growth analysis measurements have been used to explain growth rate differences among grass species and cultivars. The objective of this experiment was to study the growth of six commercially available Kentucky bluegrass cultivars from different growth habit classifications using classical growth analysis. Kentucky bluegrass seed was germinated and transplanted into cone‐tainers and transferred to a growth chamber maintained at 25/15°C (day/night) and a 12‐h photoperiod. Thirty plants per cultivar were used with six whole plants of each cultivar harvested 8 weeks after transplanting and once per week for the next 4 weeks for a total of five harvests. Barvette HGT produced the largest plants, and Moonlight SLT produced the smallest plants by the end of the experiment, although the relative growth rate and absolute growth rate did not vary between the cultivars. Results from the growth analysis revealed that Moonlight SLT had the highest leaf area ratio (89.4 cm2 g−1), specific leaf area (200.1 cm2 g−1), and rhizome weight ratio (0.101 g g−1), but the lowest stem weight ratio (0.120 g g−1) and root weight ratio (0.338 g g−1). Final plant weights and leaf area measurements were closely aligned with Kentucky bluegrass classification information. Unfortunately, classical growth analysis provided little insight into why some cultivars possess more aggressive growth characteristics or compact growth habits. Core Ideas: Modern Kentucky bluegrass cultivars used for turfgrass had similar relative growth rates.Whole plant mass and leaf area measurements were consistent with Kentucky bluegrass growth habit classifications.Classical growth analysis provided little insight into why some cultivars grow more aggressively than others. [ABSTRACT FROM AUTHOR]

This study investigated the differences in stem and leaf growth characteristics of Medicago sativa and Bromus inermis in the Jiaozhou region of China during 2019–2020 under three different planting modes of the two forages: monoculture, mixed species sowing in the same rows, and mixed species sowing in alternating rows. No special management of the experimental plots was carried out in this study to simulate as much as possible the growth of forages in their natural state. The stem and leaf characteristics influencing the dry matter weight were calculated using grey correlation. These characteristics included leaf length, leaf width, leaf thickness, leaf area, leaf fresh weight, stem length, stem diameter, stem fresh weight, stem–leaf ratio, fresh matter yield, dry matter yield, and protein yield of M. sativa and B. inermis under different sowing methods in different years. The results showed that the weight pattern of the characteristics affecting the yield of M. sativa and B. inermis production was leaf area > stem diameter > leaf length > stem length > leaf width > leaf thickness, leaf area > leaf length > stem length > leaf width > leaf thickness > stem diameter. Considering all the growth factors, the production capacity was ranked as mixed sowing in alternating rows > mixed sowing in same rows > monoculture. Thus, the suitable mode for M. sativa–B. inermis sowing was mixed sowing in alternating rows. [ABSTRACT FROM AUTHOR]

Background and Aims Plasticity of leaf growth and photosynthesis is an important strategy of plants to adapt to shading stress; however, their strategy of leaf development to achieve a simultaneous increase in leaf area and photosynthesis under shading remains unknown. Methods In the present study, a pot experiment was conducted using three rapeseed genotypes of Huayouza 50 (HYZ50), Zhongshuang 11 (ZS11) and Huayouza 62 (HYZ62), and the responses of plant growth, leaf morphoanatomical traits, cell wall composition and photosynthesis to shading were investigated. Key Results Shading significantly increased leaf area per plant (LA plant) in all genotypes, but the increase in HYZ62 was greater than that in HYZ50 and ZS11. The greater increment of LA plant in HYZ62 was related to the larger decrease in leaf mass per area (LMA) and leaf density (LD), which were in turn related to less densely packed mesophyll cells and thinner cell walls (T cw). Moreover, shading significantly increased photosynthesis in HYZ62 but significantly decreased it in HYZ50. The enhanced photosynthesis in HYZ62 was related to increased mesophyll conductance (g m) due primarily to thinner cell walls. Conclusions The data presented indicate that the different plasticity of mesophyll cell density, cell wall thickness and cell wall composition in response to shading can dramatically affect leaf growth and photosynthesis. [ABSTRACT FROM AUTHOR]

Plant growth is a complex process affected by a multitude of genetic and environmental factors and their interactions. To identify genetic factors influencing plant performance under different environmental conditions, vegetative growth was assessed in Arabidopsis thaliana cultivated under constant or fluctuating light intensities, using high-throughput phenotyping and genome-wide association studies. Daily automated non-invasive phenotyping of a collection of 382 Arabidopsis accessions provided growth data during developmental progression under different light regimes at high temporal resolution. Quantitative trait loci (QTL) for projected leaf area, relative growth rate, and PSII operating efficiency detected under the two light regimes were predominantly condition-specific and displayed distinct temporal activity patterns, with active phases ranging from 2 d to 9 d. Eighteen protein-coding genes and one miRNA gene were identified as potential candidate genes at 10 QTL regions consistently found under both light regimes. Expression patterns of three candidate genes affecting projected leaf area were analysed in time-series experiments in accessions with contrasting vegetative leaf growth. These observations highlight the importance of considering both environmental and temporal patterns of QTL/allele actions and emphasize the need for detailed time-resolved analyses under diverse well-defined environmental conditions to effectively unravel the complex and stage-specific contributions of genes affecting plant growth processes. [ABSTRACT FROM AUTHOR]

The establishment of crop growth models enables the simulation of the impacts of environmental changes on crop growth, providing theoretical guidance for exploring the relationship between environmental factors and crop growth. The model used the growth cycle (GC) as the simulation time step and was built upon four submodels: topology, photosynthesis, biomass allocation, and geometric morphology. It was quantitatively utilized the concept of effective accumulated temperature (EAT) and parameters such as sink and expansion rate were used to explain the allometric growth relationships among different organs. The R2 values for the geometric morphological parameters such as leaf length, leaf width, leaf area, and internode volume ranged from 0.78 to 0.94, while the F-values for the regression equations ranged from 1533.53 to 13949.51. The R2 values for simulating leaf, internode, and earhead biomass were 0.62-0.94, 0.74-0.97, and 0.98, respectively, with RMSE values ranging from 0.02 to 0.13 g for leaf biomass, 0.03 to 0.13 g for internode biomass, and 1.71 g for earhead biomass. The results indicated that the model exhibited good performance and reliability in simulating the growth and development of leaves, internodes, and earheads. This provides a solid foundation for the development of a millet model with functional-structural feedback. [ABSTRACT FROM AUTHOR]

Maize (Zea mays), a cold‐sensitive crop, requires cold tolerance for extending the length of the growing season in temperate climates. However, response curves to different cold temperatures and exposure durations are lacking. We used a meta‐analysis approach using data from literature to investigate the effect of cold stress in the maize leaf. We constructed response curves to temperature and exposure durations for 18 key parameters related to leaf growth, photosynthesis, oxidative stress, antioxidants, and the phytohormone ABA. To determine their relevance for cold tolerance, we compared cold tolerant Flint and cold sensitive Dent lines. Treatment temperatures ranged from −20°C to 20°C for cold and from 12°C to 30°C for control and exposure duration from 3 min to 60 days. We found interacting effects of temperature and exposure durations on different response parameters. The strongest difference between Flint and Dent was observed for electrolyte leakage (EL). Our results show that the commonly used 4°C for cold and 25°C for control with medium cold exposure (1−7 days) induces a 50% decrease in shoot dry weight and leaf area and that EL is an easy and reliable indicator for cold tolerance studies. Summary Statement: Meta‐analysis of cold stress responses in the Zea mays leaf reveals differences in response curves of physiological parameters and shows that electrolyte leakage is a reliable indicator for cold tolerance. [ABSTRACT FROM AUTHOR]

【Objective】 The purpose was to study the effects of nitrogen application and leaves retention on the yield and quality of yellow sun-cured tobacco. 【Method】 Using the yellow sun-cured tobacco variety ‘Cunsanpi’ as the material, a split-area experimental design was adopted, and the two-factor experiments of nitrogen application of 82.5, 97.5, 112.5 and 127.5 kg/hm² and the number of leaves retained of 16, 19 and 22 leaves/plant (Total 12 treatments) were conducted to study its effects on the agronomic traits, yield, average price, yield value and appearance quality of yellow sun-cured tobacco. 【Result】 The results showed that increased nitrogen fertilization could promote the growth of tobacco plant and increase nitrogen metabolism, and at the same time, it was conducive to the improvement of agronomic traits such as stem girth, pitch, leaf length and width, and leaf area. Within a certain range of nitrogen application, tobacco yield increased with the increase in the number of leaves retained. Within a certain range of the number of leaves, the tobacco yield varied with the nitrogen application. When the number of leaves was 16 leaves/plant and 22 leaves/plant, the tobacco yield showed an upward trend with the increase of nitrogen application. When the number of retained leaves was 19 leaves/plant and the applied nitrogen ranged from 82.5 kg/hm² to 112.5 kg/hm², the tobacco yield increased with the increase of applied nitrogen. From the same level of nitrogen application of different number of leaves of tobacco leaf yield changes, when the nitrogen application of 127.5 kg/hm², the tobacco yield with the increase in the number of leaves of tobacco leaf is a downward trend. When the nitrogen application was 112.5 kg/hm² and the number of retained leaves was 19 leaves/plant, the tobacco leaf yield value was the highest, which was 54 567.00 yuan/hm². When the nitrogen applications were 82.5 kg/hm² and 97.5 kg/hm², the tobacco leaf yield value increased with the increase of the number of retained leaves. From the point of view of the average price of tobacco with different number of leaves of the same nitrogen application, when the nitrogen application was 82.5 kg/hm² and 127.5 kg/hm², the average price of tobacco showed a decreasing trend with the increase of the number of leaves of the same application. When the N application was 97.5 kg/hm², the average price of tobacco leaf increased with the increase of the number of retained leaves. When the nitrogen application was 112.5 kg/hm², the average price of tobacco leaf increased and then decreased with the number of leaves retained, and was higher in the treatment with 19 leaves/plant. The appearance quality of tobacco leaf was better in three treatments: 82.5 kg/hm² of nitrogen application, 16 leaves/plant; 97.5 kg/hm² of nitrogen application, 22 leaves/plant and 127.5 kg/hm² of nitrogen application, 19 leaves/plant. 【Conclusion】 Under the conventional cultivation condition of ensuring density of 15 150 plants/hm², applying nitrogen at 112.5 kg/hm² and retaining leaves at 19 leaves/plant, the yellow sun-cured tobacco variety ‘Cunsanpi’ could obtain better economic benefits in Fuquan, Guizhou. [ABSTRACT FROM AUTHOR]

Introduction: Leaves are important organs for photosynthesis in plants, and the restriction of leaf growth is among the earliest visible effects under abiotic stress such as nutrient deficiency. Rapidly and accurately monitoring plant leaf area is of great importance in understanding plant growth status in modern agricultural production. Method: In this paper, an image processing-based non-destructive monitoring device that includes an image acquisition device and image process deep learning net for acquiring Brassica napus (rapeseed) leaf area is proposed. A total of 1,080 rapeseed leaf image areas from five nutrient amendment treatments were continuously collected using the automatic leaf acquisition device and the commonly used area measurement methods (manual and stretching methods). Results: The average error rate of the manual method is 12.12%, the average error rate of the stretching method is 5.63%, and the average error rate of the splint method is 0.65%. The accuracy of the automatic leaf acquisition device was improved by 11.47% and 4.98% compared with the manual and stretching methods, respectively, and had the advantages of speed and automation. Experiments on the effects of the manual method, stretching method, and splinting method on the growth of rapeseed are conducted, and the growth rate of rapeseed leaves under the stretching method treatment is considerably greater than that of the normal treatment rapeseed. Discussion: The growth rate of leaves under the splinting method treatment was less than that of the normal rapeseed treatment. The mean intersection over union (mIoU) of the UNet-Attention model reached 90%, and the splint method had higher prediction accuracy with little influence on rapeseed. [ABSTRACT FROM AUTHOR]

Chaya (Cnidoscolus aconitifolius (Mill.) I.M. Johnst.) is a perennial leafy vegetable. Since the leaf blade is the most crucial component of the Chaya, it should be advantageous to estimate the leaf area nondestructively. This research aimed to (a) develop a beneficial nondestructive model for leaf area estimation, and (b) ascertain the impact of stem cutting diameter when used as planting material on chaya growth rate. The results demonstrated that utilizing the length x width (LW) of the middle lobe as the predictor and the zero intercepts linear regression LA = 1.679 LW with R2=0.947 determination coefficient was the most dependable model for Chaya plant leaf area estimation. The stem diameter, which ranged from 9.9 to 17.3 mm, had affected the shoot length, number of leaves, and canopy area between 5 and 7 weeks after planting (WAP). The variations in growth metrics diminished along with the age of plants. The diameter of the stem cutting used as planting material had no effect on the fresh weight of young edible shoot tip at 11 WAP. On Chaya plants that were cultivated with larger stem cutting diameters, the fresh leaf weight at the branch tips was heavier. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to explore the physiological and biochemical response of Nymphaea minuta to low light environment, and to provide theoretical basis for seedling breeding and potted flower production management of micro-tropical water lily represented by N.minuta. 【Method】 A completely random experimental design was conducted. The shading treatments were set to 0(total illumination control, CK), 30% (light shading), 50% (medium shading), 70% (heavy shading) respectively by constructing shading nets with different layers. The number of leaves, leaf dry weight, leaf area and other growth indicators were measured by shading treatment for 120 days. The content and composition of photosynthetic pigments, soluble sugar, soluble protein and starch contents were measured by shading treatment for 30, 60, 90 and 120 days respectively. The effects of different shading conditions on leaf growth, photosynthetic pigment content and primary metabolites content of N.minuta were analyzed. 【Result】 During the shading period of 30-120 days, there were no significant differences between the average leaf area, photosynthetic pigment content, and soluble protein content of N.minuta treated with shading rate of 30%, 50% and CK (P＞0.05). After shading treatment for 120 days, the leaf number, average leaf dry weight, specific leaf weight, soluble sugar content, soluble protein content and starch content of N.minuta decreased with increasing shading rate, while total chlorophyll content, chlorophyll a content, chlorophyll b content, chlorophyll a/b content and carotenoid content all increased with increasing shading rate. Comparing with CK, the shading rate of 70% at 120 days treatments, the leaf number, average leaf dry weight and specific leaf weight of N.minuta were significantly decreased by 52.9%, 81.3% and 57.8%, respectively (P＜0.05, the same as below), total chlorophyll content, chlorophyll a content, chlorophyll b content and carotenoid content were significantly increased by 108.7%, 81.6%, 237.5% and 88.2% respectively, chlorophyll a/b content was significantly decreased by 39.1%, soluble sugar content, soluble protein content and starch content were significantly decreased by 43.4%, 56.2% and 53.2% respectively. The results of correlation analysis showed that the leaf number and average leaf dry weight were extremely positively correlated with soluble protein content (P＜0.01, the same as below), and the average leaf dry weight was negatively correlated with total chlorophyll content, chlorophyll a content, chlorophyll b content and carotenoid content. 【Conclusion】 N.minuta grew well in light and medium shading environments with shading rates of 30% and 50%, showing good light adaptive response and regulation ability. These two shading methods can be used for reference in the breeding of micro-tropical waterlily seedlings and potted flower production management. [ABSTRACT FROM AUTHOR]

Phalaenopsis orchids are highly economical ornamental potted plants. Controlling their production schedule requires information on the leaf development characteristics of the orchids. Phalaenopsis leaves affect the plant's photosynthesis, respiration, and transpiration. The leaf growth conditions can serve as a development index for greenhouse management. The use of the growth characteristics of Phalaenopsis leaves as the basis for greenhouse cultivation and management needs to be studied. The allometry of Phalaenopsis leaves is worth studying. The goal of this research was to investigate the allometry of Phalaenopsis leaves and develop prediction models of the total leaf area. Then, these total leaf area models were developed and validated. In this study, five Phalaenopsis varieties (amabilis, Sin-Yuan beauty, Ruey Lish beauty, Ishin KHM1095, and Sogo F1091) were selected. Each sample had five mature leaves. The lengths, widths, and areas of the sequential leaves were measured, and then the length ratios, width ratios, and area ratios were calculated. The top and bottom models were used to calculate the total leaf areas. The results indicate that no significant differences could be found in the length ratios, width ratios, and area ratios of the sequential leaves from the same variety. However, significant differences were found in these leaf characteristics between different varieties. The observation of leaf growth characteristics can be used to provide useful information for Phalaenopsis management. Comparing the predictive criteria of the two models, the top model had a better predictive ability than the bottom model. From a practical viewpoint, measuring the top leaf area is easier than measuring the bottom leaf area in a greenhouse operation. Comparing the effects of the sample numbers on the predictive ability of the model, the sample number of 30 was sufficient to ensure the accuracy of the total leaf area measurements. We provide an easy and accurate method to measure the total leaf area of Phalaenopsis. The calculated values of total leaf areas can be incorporated into decision models for smart management. [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]

Populus spp. are among the fast-growing tree species most prone to water deficit. The use of drought-resistant clones allows mitigating the negative effects of water deficit on the establishment and the productivity of unstable irrigated plantations in dryland areas. We evaluated the responses of four Populus × canadensis ('Conti 12', 'Guardi', 'I-214' and 'I45/51') and four Populus deltoides ('Stoneville 67', 'Catfish 2', 'Dvina' and 'Australiano 129/60') clones to a short-term water stress. Three water treatments were imposed on 6-month-old plants: well-watered (WW), 5 days of irrigation withdrawal followed by rewatering (−5 + RW), and 9 days of irrigation withdrawal followed by rewatering (−9 + RW). Populus clones presented different strategies to face water deficit, resulting in variable effects on plant growth. The small-leaved clone 'Australiano 129/60' showed strong stomatal control and maintained a high increase in leaf area during the water-shortage period. These strategies were associated with high relative growth under both water-shortage treatments. 'Australiano 129/60' showed to be a drought-resistant clone with the highest growth under both water-shortage treatments, appearing to be a promising clone for production in environments prone to short-term water stress. [ABSTRACT FROM AUTHOR]

Leaf traits can reflect plant photosynthetic capacity, resource utilization strategy and adaptability to the environment. However, whether species' leaf traits are tightly related to the functioning of their community and how that relationship varies with environmental gradients remain largely unexplored. We measured 6 leaf traits, including petiole fineness (PF), specific leaf area (SLA), leaf area (LA), leaf length–width ratio (LLWR), leaf nitrogen content (LN) and leaf phosphorus content (LP), of 733 populations (415 species) of 19 woody angiosperm communities in the eastern Qinghai–Tibetan Plateau across multiple climatic zones or vegetation types. Through meta-analysis and relative importance analysis, the relationship between leaf traits of species and their community dominance and its change with environments were analyzed. The results showed that species dominance was correlated positively with their LA and LP, suggesting that species with high light interception and resource utilization capacity can easily become dominant species in woody angiosperm communities. Along the altitudinal gradient, the effect of PF and SLA on species dominance increased and changed significantly in their pattern, from positive or nonsignificant in temperate forests to negative in alpine and subalpine shrubs, suggesting that increasing petiole mechanical support and lamina protection cost is a dominant leaf growth strategy in stressful high-altitude environments. Our findings demonstrate that the demand for efficient light acquisition and/or utilization and species adaptability or tolerance to specific environmental stress are key mechanisms by which leaf traits govern community composition and functioning. [ABSTRACT FROM AUTHOR]

Dendrobium cut-flower producers commonly employ sprinkler systems with high water consumption. Our study aimed to identify a more water-efficient irrigation method for orchids. Specifically, we investigated the optimal timing of water application during a day in the dry season, intending to minimize water usage. The research used a 3x2x2 completely randomized factorial design, factoring in the times of the day for irrigation (dawn, morning, and evening), the type of sprinkler head (standard or large vs. mini), and the duration of irrigation (6 minutes vs. 4 minutes). The study revealed that adjusting these factors could reduce the standard water volume used by 30 to 60% without negatively affecting the orchids' growth or flower quality. Over five months of testing various irrigation techniques, metrics such as the height of the front pseudobulb, leaf count on the front pseudobulb, total leaf number per plant, pseudobulb count, and inflorescence quality (like length, number of flowers, and vase life) remained consistent across different methods. A notable discovery was that irrigating at either dawn or evening using a standard-sized sprinkler led to higher fresh and dry leaf weights and a greater leaf area than morning irrigation. Impressively, these results were observed even when the irrigation time was reduced tojust 4 minutes, a 30% reduction from typical water usage. In summary, our research suggests that during the dry season, Dendrobium orchid growers can potentially reduce irrigation water usage by 30% without sacrificing the growth or quality oftheir plants. [ABSTRACT FROM AUTHOR]

[Objectives] The purpose of this study was to investigate the regulation and mechanism of hydrogen-rich water (HRW)on the growth and photosynthesis of strawberry (Fragaria×ananassa Duch.). This would benefit agriculture by the application of HRW. [Methods]HRW was used to irrigate strawberries, and parameters such as leaf growth, photosynthetic gas exchange and photosynthetic efficiency were determined. Surface water irrigation was as the control. [Results]After the treatment, the leaf area of strawberries increased, the dry weight and fresh weight of leaves increased by 57.7% and 60.4%, respectively, and the relative growth rate and net assimilation rate increased by 50.0% and 59.9%, respectively, indicating that HRW had a significant effect in promoting strawberry growth. After HRW treatment, the chlorophyll a content increased by 14.4%, the chlorophyll b content did not change significantly, and the net photosynthetic rate of leaves increased by 22.3%, the contents of soluble sugar, glucose and sucrose in leaves significantly increased. After HRW treatment, the electron transport rate of PSⅡ increased but was not significant, while the significant decrease of quantum yield of photosystems Ⅱ nonregulatory energy dissipation Y(NO)indicated that the protection and regulation ability of the PSⅡ of strawberry leaves was improved. While the electron transport rate of PSⅠ and effective photochemical quantum yield Y(I) significantly increased, suggesting that the cyclic electron flow of PSⅠ was improved. Further analysis showed that the transmembrane proton gradient(ΔpH)was significantly higher than that of the control, accounting for the main part of proton motive force, and the ATP content increased by 43.9% compared with the control, confirming the cyclic electron flow results. [Conclusions]Hydrogen-rich water can promote growth and photosynthesis of strawberry leaf by enhancing cyclic photosynthesis electron flow. [ABSTRACT FROM AUTHOR]

Adaptability of the Swiss chard to the tropical climate opens opportunity to grow this leafy vegetable all year around. Colorful petiole and leaf blade of this vegetable have attracted urban community to grow them. Objectives of this research were to study the morphological and growth characteristics of the Swiss chard, especially leaf growth rate, time to reach full size, and non-destructive measurement of the leaf area. The Swiss chards used were red, pink, and yellow petiole cultivars. The plants were cultivated using the floating culture system. Relative leaf elongation and widening rates were higher at early leaf development, i.e. soon after the leaf blade was unfolded. Then, the rates were gradually declined and completely halted at about 12 days. In this study, combination of the zero-intercept linear model and the length × width (LW) as predictor were accurate for estimation leaf area (LA) of the red (R² =0.981), pink (R² =0.975), and yellow (R² =0.980) petiole cultivars. The non-destructive measurement on selected morphological and/or weight traits should be useful for continuously monitoring of leaf growth, predicting yield at any time during plant growth, and determining the time to harvest. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental 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.)

Uganda lies within the drier end of the natural distribution range of Coffea canephora and contains unexplored genetic material that could be drought‐adapted and useful for developing climate‐resilient varieties. Using water treatment: (i) ample and (ii) restricted‐water, the response of 148 genotypes were studied comprising wild, feral and cultivated C. canephora. Biomass allocation, standing leaf area and leaf area growth data were collected. Linear mixed effect models and PCA were used to the analyze effect of water treatment on genotypes from different: (i) cultivation status, (ii) genetic groups and (iii) locations. We also assessed the relationship between drought tolerance for relative growth rate in leaf area (RGRA), total number of leaves (TNL), total leaf area (TLA) and total leaf dry weight (TLDW) of genotypes at final harvest. Restricted‐water reduced RGRA across genetic groups (3.2–32.5%) and locations (7.1–36.7%) but not cultivation status. For TNL, TLA and TLDW, genotypes that performed well in ample‐water performed worse under restricted‐water, indicating growth‐tolerance trade‐off. Drought tolerance in RGRA and TNL were negatively correlated with wetness index suggesting some degree of adaptation to local climate. Findings indicate a growth‐tolerance trade‐off within this tropical tree species and drought tolerance of Uganda's C. canephora is somewhat associated with local climate. [ABSTRACT FROM AUTHOR]

The study aimed to test whether night‐time transpiration provides any potential benefit to wheat plants which are subjected to salt stress. Hydroponically grown wheat plants were grown at four levels of salt stress (50, 100, 150, and 200 mM NaCl) for 5–8 days prior to harvest (day 14–18). Salt stress caused large decreases in transpiration and leaf elongation rates during day and night. The quantitative relation between the diurnal use of water for transpiration and leaf growth was comparatively little affected by salt. Night‐time transpirational water loss occurred predominantly through stomata in support of respiration. Diurnal gas exchange and leaf growth were functionally linked to each other through the provision of resources (carbon, energy) and an increase in leaf surface area. Diurnal rates of water use associated with leaf cell expansive growth were highly correlated with the water potential of the xylem, which was dominated by the tension component. The tissue‐specific expression level of nine candidate aquaporin genes in elongating and mature leaf tissue was little affected by salt stress or day/night changes. Growing plants under conditions of reduced night‐time transpirational water loss by increasing the relative humidity (RH) during the night to 95% had little effect on the growth response to salt stress, nor was the accumulation of Na+ and Cl− in shoot tissue altered. We conclude that night‐time gas exchange supports the growth in leaf area over a 24 h day/night period. Night‐time transpirational water loss neither decreases nor increases the tolerance to salt stress in wheat. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted to understand the effects of water and nitrogen (N) on net root productivity, root longevity, root length, and canopy characteristics of cotton (Gossypium hirsutum L.), and to quantify the associations between canopy characteristics and indicators of root dynamics. Methods: A two-year field experiment was performed to evaluate the variation in canopy growth and root dynamics of cotton in response to three nitrogen levels (320 kg ha−1, high N; 272 kg ha−1, moderate N; 224 kg ha−1, low N) and two water levels (400 mm, high-water group; 267 mm, low-water group) during the growing seasons of 2019 and 2020 in Xinjiang, China. Results: Plants exposed to low-water environments increased root longevity more than all other high-water treatments. Under high-water conditions, a moderate N rate obtained a higher root longevity compared to high-N and low-N treatments. Net root productivity (NRP) was strongly associated with leaf area expansion rate and leaf number. A moderate N rate under high-water conditions exhibited a significant 30.0% increase in NRP, resulting in a relatively high leaf area and the highest leaf relative water content, and had an equivalent canopy photosynthetic rate compared with high-N plots. Plants receiving moderate N in the high-water group had greater total root length by increasing root longevity and productivity. Conclusions: Estimates of NRP may need to be included along with leaf growth estimates in future efforts to scale from root to canopy level developmental performance in cotton. [ABSTRACT FROM AUTHOR]

Exogenous application of salicylic acid (SA) to plant tissues has been shown to confer tolerance against various abiotic stresses. Recently, SA application through sub-irrigation was shown to improve plant freezing tolerance (FT). For SA treatment to be employable as an effective intervention strategy for frost protection under field conditions, it is important to study its effect on FT when applied as a foliar spray to whole plants. It is also important to determine for how long the FT-improvement by SA lasts. Present study was conducted to compare SA-induced FT of spinach (Spinacia oleracea L. 'Reflect') seedlings following SA-application by foliar spray vs. sub-irrigation. Durability of FT-promotive effect of SA was evaluated using three freeze-tests over a 4-d period, i.e., at 10-d, 12-d, and 14-d after the SA application. Freezing stress was applied using a temperature-controlled freeze-thaw protocol, and FT was assessed by visual observations (leaf flaccidness vs. turgidity) as well as ion-leakage assay. Data indicated that both foliar spray and sub-irrigation methods improved FT of the seedlings against a relatively moderate (−5.5 °C) as well as severe stress (−6.5 °C). Moreover, improved FT against moderate stress was sustained over a 4-d period, whereas such benefit waned somewhat against the severe stress. SA-treated leaves' growth performance was similar to the non-treated control based on dry weight, fresh weight, leaf area, and dry weight/leaf area parameters. Our results suggest that SA application as a foliar spray can potentially be used to protect field-grown transplants against episodic frosts. [ABSTRACT FROM AUTHOR]

Background: Leaf size affects crop canopy morphology and photosynthetic efficiency, which can influence forage yield and quality. It is of great significance to mine the key genes controlling leaf development for breeding new alfalfa varieties. In this study, we mapped leaf length (LL), leaf width (LW), and leaf area (LA) in an F1 mapping population derived from a cultivar named ZhongmuNo.1 with larger leaf area and a landrace named Cangzhou with smaller leaf area. Results: This study showed that the larger LW was more conducive to increasing LA. A total of 24 significant quantitative trait loci (QTL) associated with leaf size were identified on both the paternal and maternal linkage maps. Among them, nine QTL explained about 11.50–22.45% phenotypic variation. RNA-seq analysis identified 2,443 leaf-specific genes and 3,770 differentially expressed genes. Combining QTL mapping, RNA-seq alalysis, and qRT-PCR, we identified seven candidate genes associated with leaf development in five major QTL regions. Conclusion: Our study will provide a theoretical basis for marker-assisted breeding and lay a foundation for further revealing molecular mechanism of leaf development in alfalfa. [ABSTRACT FROM AUTHOR]

Leaf growth relies on photosynthesis and hydraulics to provide carbohydrates and expansion power; in turn, leaves intercept light and construct organism systems for functioning. Under potassium (K) deficiency stress, leaf area, photosynthesis and hydraulics are all affected by alterations in leaf structure. However, the connection between changes in leaf growth and function caused by the structure under K regulation is unclear. Consequently, the leaf hydraulic conductance (Kleaf) and photosynthetic rate (A) combined with leaf anatomical characteristics of Brassica napus were continuously observed during leaf growth under different K supply levels. The results showed that Kleaf and A decreased simultaneously after leaf area with the increasing K deficiency stress. K deficiency significantly increased longitudinal mesophyll cell investment, leading to a reduced volume fraction of intercellular air‐space (fias) and decreased leaf expansion rate. Furthermore, reduced fias decreased mesophyll and chloroplast surfaces exposed to intercellular airspace and gas phase H2O transport, which induced coordinated changes in CO2 mesophyll conductance and hydraulic conductance in extra‐xylem pathways. Adequate K supply facilitated higher fias through smaller palisade tissue cell density (loose mesophyll cell arrangement) and smaller spongy tissue cell size, which coordinated CO2 and H2O conductance and promoted leaf area expansion. [ABSTRACT FROM AUTHOR]

During Populus euphratica ontogeny, the morphological changes of stems and leaves, nutrient and endogenous hormone contents were significantly different, but the relationship between these changes and the number of flower buds was not clear. We counted the number of P. euphratica flower buds, and measured the morphological of the stems and leaves nutrient and endogenous hormone contents at different ontogeny to clarify the change trends in the morphology and nutrient and endogenous hormone contents of stems and leaves and mutual relationships in the flower bud number throughout the ontogeny. The results showed that in diameter 4, flower buds and broad-ovate leaves appeared meanwhile, indicating that P. euphratica had entered the reproductive growth stage. Between diameter 4 to 12, stem length, leaf number and leaf C/N gradually decreased, and leaf area, leaf nitrogen, organic carbon, and ZR contents gradually increased, indicating diameters 4-12 represent the stage during which vegetative growth and reproductive growth cooccur in P. euphratica. In diameter 14, flower bud number increased significantly, while leaf shape index and stem diameter decreased. P. euphratica began to enter the vigorous reproductive growth stage. In addition, correlations were found between leaf and stem nitrogen, phosphorus, organic carbon, GA3, ABA, IAA contents, leaf C/N and leave and stem morphology was closely related to the ontogeny; the change in coordination significantly affected the flower bud number. The synergistic changes in the nutrient and endogenous hormone contents in P. euphratica stems and leaves regulate the morphology of stems and leaves and flower bud number and directly or indirectly affect the transition from vegetative growth to reproductive growth. [ABSTRACT FROM AUTHOR]

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To screen soil nutrients and light conditions that effectively promote the growth of Picea koraiensis saplings and to provide a scientific basis for establishing growth promotion techniques for P. koraiensis saplings, a split-zone design experiment was conducted with P. koraiensis saplings plantations of 8-10 years old in Jiamusi City, Heilongjiang Province, using three light conditions (full light, 0. 5 depression, 0. 7 depression) with nitrogen addition (100 g / plant-yr) and control plots to analyze the effects of light and nitrogen addition on growth and leaf morphological function of P. koraiensis saplings. The results showed that: The annual growth of tree height was the highest under full light conditions, and the annual growth of ground diameter was the highest under full light fertilization conditions, followed by 0. 5 degree of depression; the effect of N addition on the annual growth of tree height and ground diameter was small. Between different light conditions, with the increase of canopy density, the specific leaf area and chlorophyll content increased, leaf dry matter content and chlorophyll a/b decreased, and leaf nutrient content did not change significantly; the effect of N addition on leaf morphology, chlorophyll content and leaf nutrient content was not significant. The effect of light on the growth, leaf morphology and photosynthetic capacity of P. koraiensis saplings was more significant than that of N addition, and saplings under full light and N addition had larger annual growth of tree height and ground diameter, and the lowest annual growth ratio of high diameter. Nitrogen addition can promote the photosynthetic efficiency of saplings. The full light condition or nearly full light condition should be selected for the forestation of P. koraiensis, and the photosynthetic capacity of saplings can be improved by nitrogen addition after forestation to promote growth. [ABSTRACT FROM AUTHOR]

Plant functional traits can reflect response strategies of plants to environmental changes. In this study, we used a one-way ANOVA and redundancy(RDA)to compare the differences in leaf functional characters of Dicranopteris pedata in three micro-topographies(ridge, slope and valley of the ephemeral gully)and to analyze the response and adaptation strategy of D. pedata to shallow trench micro-topography. The results were as follows:(1)The overall variation degree of leaf functional characters of D. pedata was between 0.05 and 0.47. Both leaf thickness and leaf area were showed as the order of valley > slope > ridge(P<0.05). The leaf N content at the slope was significantly higher than that at the ridge and valley. The leaf P content was significantly lower at the ridge than those at the slope and valley. There was no significant differences in specific leaf area and leaf C content among three micro-topographies.(2)D. pedata at the ridge reduced water loss to protecte itself by reducing leaf area. D. pedata at the slope increased the photosynthetic rate of leaves to promote growth by increasing the N content of leaves. D. pedata at the valley improved light capture ability to promote growth by increasing the leaf area. The above results indicate that due to the differences of soil nutrients, temperature and humidity conditions, D. pedata can achieve better adaption to the environment by adjusting nutrient content and changing leaf morphology. [ABSTRACT FROM AUTHOR]

Photosynthetic light response curve parameters help us understand the interspecific variation in photosynthetic traits, leaf acclimation status, carbon uptake, and plant productivity in specific environments. These parameters are also influenced by leaf traits which rely on species and growth environment. In accessions of four amaranth species (Amaranthus. hybridus, A. dubius, A. hypochondriacus, and A. cruentus), we determined variations in the net photosynthetic light response curves and leaf traits, and analysed the relationships between maximum gross photosynthetic rate, leaf traits, and whole-plant productivity. Non-rectangular hyperbolae were used for the net photosynthesis light response curves. Maximum gross photosynthetic rate (Pgmax) was the only variant parameter among the species, ranging from 22.29 to 34.21 μmol m–2 s–1. Interspecific variation existed for all the leaf traits except leaf mass per area and leaf inclination angle. Stomatal conductance, nitrogen, chlorophyll, and carotenoid contents, as well as leaf area correlated with Pgmax. Stomatal conductance and leaf nitrogen explained much of the variation in Pgmax at the leaf level. At the plant level, the slope between absolute growth rate and leaf area showed a strong linear relationship with Pgmax. Overall, A. hybridus and A. cruentus exhibited higher Pgmax at the leaf level and light use efficiency at the whole-plant level than A. dubius, and A. hypochondriacus. Thus, A. hybridus and A. cruentus tended to be more efficient with respect to carbon assimilation. These findings highlight the correlation between leaf photosynthetic characteristics, other leaf traits, and whole plant productivity in amaranths. Future studies may explore more species and accessions of Amaranthus at different locations or light environments. [ABSTRACT FROM AUTHOR]

Carbon and water are two main factors limiting leaf expansion. Restriction of leaf growth by low availability of carbon or water is among the earliest visible effects of potassium (K) deficiency. It is not known how K is involved in regulating the rhythmic supply of these two substrates, which differ remarkably across the day–night cycle, affecting leaf expansion. We investigated the effects of different K regimes on the time courses of leaf expansion, carbon assimilation, carbohydrates, and hydraulic properties of Brassica napus. Potassium supply increased leaf area, predominantly by promoting night-time leaf expansion (>60%), which was mainly associated with increased availability of carbohydrates from photosynthetic carbon fixation and import from old leaves rather than improvement of leaf hydraulics. However, sufficient K improved leaf hydraulic conductance to balance diurnal evaporative water loss and increase the osmotic contribution of water-soluble carbohydrates, thereby maintaining leaf turgor and increasing the daytime expansion rate. The results also indicated an ontogenetic role of K in modifying the amplitude of circadian expansion; almost 80% of the increase in leaf area occurred before the area reached 66.9% of the mature size. Our data provide mechanistic insight into K-mediated diel coordination of rhythmic carbon supply and water balance in leaf expansion. [ABSTRACT FROM AUTHOR]

Melia azedarach is widely distributed in China and has a wide range of genetic variation. In order to study the growth characters of one-year-old seedlings of M. azedarach from different seed sources, the growth characters of seedling height, ground diameter, compound leaf growth and biomass accumulation of M. azedarach seedlings from 15 seed sources were observed, and the growth rhythm was fitted by logistic equation. The results were as follows: (1) There were significant differences between seedling height and ground diameter (P<0.05), and significant differences between root biomass, stem biomass and compound leaf (P<0.01). (2) The growth of seedling height and ground diameter showed a slow-fast-slow growth pattern with type S. Compared with the emergence time of seedling height growth peak, the emergence time of ground diameter growth peak was later. (3) The R² of logistic fitting equation was 0.976-0.994, which reached the extremely significant correlation level, indicating that the growth rhythm of M. azedarach can be fitted by logistic equation. (4) According to theoretical calculation and practical observation, the duration of fast-growing stage of ground diameter was generally 20-30 d longer than that of high-speed growth stage of seedling. The time of seedling height and ground diameter entering fast-growing stage and ending fast-growing stage in northern locality was earlier than that in southern locality. (5) All though traits were negatively correlated with latitude, seedling height, biomass and leaf area were positively correlated with longitude, while other traits were negatively correlated with longitude. In general M. azadarach begongs to full-time growth type with significant differences in growth traits among seed sources. The growth was regulated by both latitude and longitude, mainly by latitude. [ABSTRACT FROM AUTHOR]

Copyright of Revista IRRIGA - Brazilian Journal of Irrigation & Drainage is the property of Revista IRRIGA (Brazilian Journal of Irrigation & Drainage) 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 effect of nitrogen (N) nutrition on grapevine carbon (C) dynamics has been well studied at the annual scale, but poorly addressed at a pluriannual timescale. The aim of this study was to quantify, in an integrated conceptual framework, the effect of N nutrition on potted grapevine growth and storage over 2 consecutive years. The consequences of using destructive measurements were investigated using a hierarchical Bayesian model. The rate and duration of leaf growth were both positively impacted by the chlorophyll content of the leaves, but they were negatively impacted by the initial carbohydrate measurements, raising a distortion in the estimation of initial reserves. The C production per unit of global radiation depended on the leaf area dynamics. The allocation of dry matter mainly relied on the phenological stage. The present study highlights the importance of using appropriate statistical methods to overcome uncertainties due to destructive measurements. The genericity of the statistical approach presented may encourage its implementation in other agronomy studies. Based on our results, a simple conceptual framework of grapevine pluriannual growth under various N supplies was built. This provides a relevant basis for a future model of C and N balance and responses to N fertilization in grapevine. [ABSTRACT FROM AUTHOR]

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to environmental temperature, which, according to climate change scenarios, is expected to increase also in extremes. Our hypothesis was that the increase in temperature during budburst could increase the vegetative carbon sink strength reducing the carbon stock available for the reproductive activity jeopardizing flowering of the next year. In our experiment, we artificially conditioned grapevine budburst by exposing the growing shoots to different temperature regimes. Higher temperatures during the spring vegetative growth favored shoot stem extension at the detriment of shoot leaf area. This caused a reduction in vine CO2 assimilation, which, combined with the competition of the growing vegetative organs, affected the concurrent reproductive activity, with carry-over effects on the following year, resulting in a limited flower initiation in dormant buds. These results suggest that the increase in springtime temperature can alter canopy development and vine physiology, resulting in the reduction in reproductive activity with an economical negative impact on grapevine productivity. [ABSTRACT FROM AUTHOR]

The effect of silicon-based biostimulant Optysil (200 g SiO2 and 24 g Fe in 1 dm3 ) on the assimilation area and photosynthetic pigment contents of potato was investigated. Optysil was applied once at the leaf development stage (BBCH 14-16) or at the tuber initiation stage (BBCH 40-41) and twice at the leaf development and tuber initiation stages, at the dose of 0.25 dm3 ha-1 or 0.50 dm3 ha-1 in each treatment. Optysil resulted in an enlargement of assimilation area and an increase in leaf area index (LAI), leaf dry weight, chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids (Car) contents, and decreased the Chl a/Chl b ratio under water deficit conditions, but had no effect on the specific leaf area (SLA) and Chl (a + b)/Car ratio. Under periodical water deficits during potato growth, the plants produced the largest assimilation area with two Optysil applications at 0.50 dm3 ha-1, whereas the biosynthesis of photosynthetic pigments was most stimulated by Optysil at 0.25 dm3 ha-1 applied at the tuber initiation stage. Under drought conditions, leaf growth was most stimulated by Optysil application at 0.50 dm3 ha-1 at the initial potato growth period, whereas the biosynthesis of photosynthetic pigments by the double Optysil application at 0.50 dm3 ha-1. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office 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.)

Copyright of Journal of Taiwan Agricultural Research is the property of Taiwan Agricultural Research Institute, Council of Agriculture, Executive Yuan 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.)