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Leaf width is a key determinant of planting density and photosynthetic efficiency. In an effort to determine which genes regulate maize plant leaf width, we performed a genome-wide association study (GWAS) of 1.49 × 106 single nucleotide polymorphisms (SNPs) in 80 sequenced backbone inbred maize lines in Jilin Province, China, based upon phenotypic leaf width data from two years. In total, 14 SNPs were identified as being significantly related to leaf width (p < 0.000001), with these SNPs being located on chromosomes 1, 2, 3, 5, 6, 7, 8, and 9. A total of five candidate genes were identified within a mean linkage disequilibrium (LD) distance of 9.7 kb, with a significant SNP being identified within the Zm00001d044327 candidate gene. RNA was then isolated from 12 different inbred maize lines from this GWAS study cohort and was used to conduct qPCR analyses which revealed significant differences in Zm00001d044327 expression among strains exhibiting significant differences in leaf width. Based on an assessment of EMS mutant lines harboring a conserved amino acid stop mutation and two non-synonymous mutations in Zm00001d044327 that exhibited a narrow leaf width, these data suggested that Zm00001d044327 is a key regulator of maize leaf width. [ABSTRACT FROM AUTHOR]

Background and Aims Leaf area (A) is a crucial indicator of the photosynthetic capacity of plants. The Montgomery equation (ME), which hypothesizes that A is proportional to the product of leaf length (L) and width (W), is a valid tool for non-destructively measuring A for many broadleaved plants. At present, the methods used to compute L and W for the ME can be broadly divided into two kinds: using computer recognition and measuring manually. However, the potential difference in the prediction accuracy using either method has not been thoroughly examined in previous studies. Methods In the present study, we measured 540 Alangium chinense leaves, 489 Liquidambar formosana leaves and 215 Liriodendron  ×  sinoamericanum leaves, utilizing computer recognition and manual measurement methods to determine L and W. The ME was used to fit the data determined by the two methods, and the goodness of fits were compared. The prediction errors of A were analysed by examining the correlations with two leaf symmetry indices (areal ratio of the left side to the right side, and standardized index for bilateral asymmetry), as well as the leaf shape complexity index (the leaf dissection index). Key Results The results indicate that there is a neglectable difference in the estimation of A between the two methods. This further validates that the ME is an effective method for estimating A in broadleaved tree species, including those with lobes. Additionally, leaf shape complexity significantly influenced the estimation of A. Conclusions These results show that the use of computer recognition and manual measurement in the field are both effective and feasible, although the influence of leaf shape complexity should be considered when applying the ME to estimate A in the future. [ABSTRACT FROM AUTHOR]

Plant height and leaf morphology are considered complex agronomy traits; both are significantly related to nutrient utilization, lodging resistance, and photosynthetic efficiency, which ultimately affect biomass and yield. However, the molecular mechanism of leaf morphogenesis is still unclear. WOX is a group of plant-specific transcription factor families that regulate growth and development, cell division, and differentiation in plants. In the present study, we identified and characterized the m-876 mutant in barley (Hordeum vulgare L.), which exhibited an extreme reduction in leaf width and plant height. Using a map-based cloning strategy, the m-876 mutant was narrowed down to an 11.4 Mb genomic interval on the long arm of chromosome 5. By analyzing the gene annotation information and nucleotide sequences, we found that HvWOX3A (HORVU.MOREX.r3.5HG0467090) had a G-to-A substitution at the second exon in the m-876 mutant, resulting in a change of the coding amino acid from Tryptophan to a premature stop codon at the 200th amino acid position. Remarkably, the mutation of the HvWOX3A gene leads to changes in gene expression in the m-876 mutant. Collectively, our results indicate that the loss function of the HORVU.MOREX.r3.5HG0467090 gene might be responsible for the phenotypic variation in barley mutants. [ABSTRACT FROM AUTHOR]

Maize is an important food and feed crop. Under limited arable land area, the cultivation of high-density-tolerance crops is a key factor in promoting yield improvement. Leaf width and stalk strength are important influences on density tolerance in maize. However, no comprehensive transcriptomic analysis has focused on maize's leaf width and stalk strength formation mechanisms. In this study, comparative transcriptomic analyses demonstrated that significant transcriptome changes occurred regarding leaf width and stalk strength of narrow-leaved and wide-leaved maize inbred lines, with a total of 5001 differentially expressed genes (DEGs) identified. Enrichment analysis showed that phenylpropanoid biosynthesis, starch and sucrose metabolism, phytohormone signaling, amino acid metabolism, and brassinosteroid biosynthesis were significantly correlated with the formation of maize leaf shape and stalk strength and that the genes in these pathways were primarily involved in cell wall formation. Weighted gene co-expression network analysis identified 2 modules significantly correlated with leaf width and stalk strength, from which 11 hub genes were further identified. The 11 leaf and stem development genes in different pathways were validated using qRT-PCR. These findings can provide a theoretical basis for the mechanism of narrow-leaf and high-strength stalk formation in high-density-tolerance maize and contribute to the proposal of a breeding strategy for yield improvement. [ABSTRACT FROM AUTHOR]

Leaf width is a key determinant of planting density and photosynthetic efficiency. In an effort to determine which genes regulate maize plant leaf width, we performed a genome-wide association study (GWAS) of 1.49 × 106 single nucleotide polymorphisms (SNPs) in 80 sequenced backbone inbred maize lines in Jilin Province, China, based upon phenotypic leaf width data from two years. In total, 14 SNPs were identified as being significantly related to leaf width (p < 0.000001), with these SNPs being located on chromosomes 1, 2, 3, 5, 6, 7, 8, and 9. A total of five candidate genes were identified within a mean linkage disequilibrium (LD) distance of 9.7 kb, with a significant SNP being identified within the Zm00001d044327 candidate gene. RNA was then isolated from 12 different inbred maize lines from this GWAS study cohort and was used to conduct qPCR analyses which revealed significant differences in Zm00001d044327 expression among strains exhibiting significant differences in leaf width. Based on an assessment of EMS mutant lines harboring a conserved amino acid stop mutation and two non-synonymous mutations in Zm00001d044327 that exhibited a narrow leaf width, these data suggested that Zm00001d044327 is a key regulator of maize leaf width.

Plant height and leaf morphology are considered complex agronomy traits; both are significantly related to nutrient utilization, lodging resistance, and photosynthetic efficiency, which ultimately affect biomass and yield. However, the molecular mechanism of leaf morphogenesis is still unclear. WOX is a group of plant-specific transcription factor families that regulate growth and development, cell division, and differentiation in plants. In the present study, we identified and characterized the m-876 mutant in barley (Hordeum vulgare L.), which exhibited an extreme reduction in leaf width and plant height. Using a map-based cloning strategy, the m-876 mutant was narrowed down to an 11.4 Mb genomic interval on the long arm of chromosome 5. By analyzing the gene annotation information and nucleotide sequences, we found that HvWOX3A (HORVU.MOREX.r3.5HG0467090) had a G-to-A substitution at the second exon in the m-876 mutant, resulting in a change of the coding amino acid from Tryptophan to a premature stop codon at the 200th amino acid position. Remarkably, the mutation of the HvWOX3A gene leads to changes in gene expression in the m-876 mutant. Collectively, our results indicate that the loss function of the HORVU.MOREX.r3.5HG0467090 gene might be responsible for the phenotypic variation in barley mutants.

Maize is an important food and feed crop. Under limited arable land area, the cultivation of high-density-tolerance crops is a key factor in promoting yield improvement. Leaf width and stalk strength are important influences on density tolerance in maize. However, no comprehensive transcriptomic analysis has focused on maize’s leaf width and stalk strength formation mechanisms. In this study, comparative transcriptomic analyses demonstrated that significant transcriptome changes occurred regarding leaf width and stalk strength of narrow-leaved and wide-leaved maize inbred lines, with a total of 5001 differentially expressed genes (DEGs) identified. Enrichment analysis showed that phenylpropanoid biosynthesis, starch and sucrose metabolism, phytohormone signaling, amino acid metabolism, and brassinosteroid biosynthesis were significantly correlated with the formation of maize leaf shape and stalk strength and that the genes in these pathways were primarily involved in cell wall formation. Weighted gene co-expression network analysis identified 2 modules significantly correlated with leaf width and stalk strength, from which 11 hub genes were further identified. The 11 leaf and stem development genes in different pathways were validated using qRT-PCR. These findings can provide a theoretical basis for the mechanism of narrow-leaf and high-strength stalk formation in high-density-tolerance maize and contribute to the proposal of a breeding strategy for yield improvement.

Abstract Background Mitochondrion is the key respiratory organ and participate in multiple anabolism and catabolism pathways in eukaryote. However, the underlying mechanism of how mitochondrial membrane proteins regulate leaf and grain development remains to be further elucidated. Results Here, a mitochondria-defective mutant narrow leaf and slender grain 1 (nlg1) was identified from an EMS-treated mutant population, which exhibits narrow leaves and slender grains. Moreover, nlg1 also presents abnormal mitochondria structure and was sensitive to the inhibitors of mitochondrial electron transport chain. Map-based cloning and transgenic functional confirmation revealed that NLG1 encodes a mitochondrial import inner membrane translocase containing a subunit Tim21. GUS staining assay and RT-qPCR suggested that NLG1 was mainly expressed in leaves and panicles. The expression level of respiratory function and auxin response related genes were significantly down-regulated in nlg1, which may be responsible for the declination of ATP production and auxin content. Conclusions These results suggested that NLG1 plays an important role in the regulation of leaf and grain size development by maintaining mitochondrial homeostasis. Our finding provides a novel insight into the effects of mitochondria development on leaf and grain morphogenesis in rice.

Leaf area of dried Flue-cured tobacco is a reflection of climate and stage of growth of fresh tobacco in field; it also serves as the foundation for calculating a number of significant physical properties of tobacco. So the purpose of this paper was to establish a model to estimate the leaf area of dried Flue-cured tobacco in China from linear dimensions. Three Hundred eight tobacco leaves from different growing area and stalk position were sampled randomly and separated for model selection among linear, proportional and power model type and external evaluation individually. Results showed that there was a significant and strong correlation between leaf area and length×width, The equation LA = 0.495(L×W), where LA is the leaf area and L×W is the product of leaf length and width, was optimum and adequate for the estimation of leaf area of dried tobacco in China examined by Fisher’s test, Akaike delta information criterion (AIC) and Bayesian information criterion (BIC). Growing area and stalk position had minor effect on the parameter before (L×W). The equation can sufficiently predict the area of leaf for external evaluation. [ABSTRACT FROM AUTHOR]

Bio-fertilizers are in the present more and more of interest as alternative nutritive inputs. This research aim was to test different doses of yeast and caffeine on pepper growth and chlorophyll content. The experiment in controlled conditions consisted of 8 phytocosms treatments with 3 yeast and caffeine doses 1%, 2%, and 3%, one mixed treatment (2%), and the control treatment in five replications. The yeast addition promoted all the tested morphological parameters especially the middle dose tested. Caffeine treatments induced a slow growth of pepper vegetative period, even a delayed development compared with the control treatment. In conclusion, the mixed treatment was the most efficient pepper bio-fertilizer and provided the highest values of leaf length, width, seedling height, and also total chlorophyll content.

Background: Mitochondrion is the key respiratory organ and participate in multiple anabolism and catabolism pathways in eukaryote. However, the underlying mechanism of how mitochondrial membrane proteins regulate leaf and grain development remains to be further elucidated. Results: Here, a mitochondria-defective mutant narrow leaf and slender grain 1 (nlg1) was identified from an EMS-treated mutant population, which exhibits narrow leaves and slender grains. Moreover, nlg1 also presents abnormal mitochondria structure and was sensitive to the inhibitors of mitochondrial electron transport chain. Map-based cloning and transgenic functional confirmation revealed that NLG1 encodes a mitochondrial import inner membrane translocase containing a subunit Tim21. GUS staining assay and RT-qPCR suggested that NLG1 was mainly expressed in leaves and panicles. The expression level of respiratory function and auxin response related genes were significantly down-regulated in nlg1, which may be responsible for the declination of ATP production and auxin content. Conclusions: These results suggested that NLG1 plays an important role in the regulation of leaf and grain size development by maintaining mitochondrial homeostasis. Our finding provides a novel insight into the effects of mitochondria development on leaf and grain morphogenesis in rice. [ABSTRACT FROM AUTHOR]

Banana is an excellent companion crop cultivated with coconut, areca nut, coffee, or cacao. The yield performance of bananas however differs due to cultivar response to light, water, and nutrient availability in the intercropping system. The current study aims to understand the performance of different banana varieties under the areca nut shaded system by trait variation in growth, phenology, fresh bunch mass (yield), and soil nutrient balance patterns. Five banana varieties were screened in a field experiment in a high-density areca garden for vegetative traits, phenology, yield components, and nutrient budgets. Variety Amti recorded wider leaves and greater leaf area and also recorded higher bunch yield in plant and first ratoon crop than other varieties. The Velchi variety recorded the highest leaf emergence rate during winter and recorded the highest percentage of plants with a bunch in both the plant and first ratoon crops. The study revealed nutrient mining of nitrogen, phosphorous, and potassium in the areca–banana system. The effective balance of the available soil phosphorus was found to be highly negative for Grand Nain (−50.3 kg·ha−1·year−1) and negative (−23.6 kg·ha−1·year−1) for Amti. The results reveal the role of choice variety, indicator traits, and nutrient management strategies in enhancing banana productivity in agroforestry systems.

The estimative of the leaf area using a nondestructive method is paramount for successive evaluations in the same plant with precision and speed, not requiring high-cost equipment. Thus, the objective of this work was to construct models to estimate leaf area using artificial neural network models (ANN) and regression and to compare which model is the most effective model for predicting leaf area in sesame culture. A total of 11,000 leaves of four sesame cultivars were collected. Then, the length (L) and leaf width (W), and the actual leaf area (LA) were quantified. For the ANN model, the parameters of the length and width of the leaf were used as input variables of the network, with hidden layers and leaf area as the desired output parameter. For the linear regression models, leaf dimensions were considered independent variables, and the actual leaf area was the dependent variable. The criteria for choosing the best models were: the lowest root of the mean squared error (RMSE), mean absolute error (MAE), and absolute mean percentage error (MAPE), and higher coefficients of determination (R2). Among the linear regression models, the equation yˆ=0.515+0.584*LW was considered the most indicated to estimate the leaf area of the sesame. In modeling with ANNs, the best results were found for model 2-3-1, with two input variables (L and W), three hidden variables, and an output variable (LA). The ANN model was more accurate than the regression models, recording the lowest errors and higher R2 in the training phase (RMSE: 0.0040; MAE: 0.0027; MAPE: 0.0587; and R2: 0.9834) and in the test phase (RMSE: 0.0106; MAE: 0.0029; MAPE: 0.0611; and R2: 0.9828). Thus, the ANN method is the most indicated and accurate for predicting the leaf area of the sesame.

Sorghum is one of the most adaptable and undemanding forage crops cultivated in arid zones. The crop is characterized with high quality foliage, which can be used in fodder production in various forms (both in single-crop silage and in multi-crop mixtures). The purpose of the current study was to estimate the variability of the main productivity elements of sweet sorghum green mass depending on weather indicators. The initial material was presented by 180 collection samples of sweet sorghum from Russia, the USA and Ukraine. There have been used conventional breeding methods, such as hybridization, selection and inbreeding. The weather conditions during the study years of 2017–2021 were contrasting. The hydrothermal coefficient for the vegetation period of sorghum indicates that the year of 2018 was the driest one (HThC = 0.38). The variability coefficient of collection samples of sweet sorghum according to green mass productivity has shown a strong variability of this indicator (V = 27–35%). The green mass productivity had a close direct correlation with the length of a leaf (0.73±0.05) and an average correlation with its width (0.61±0.06). The variability coefficient has shown that the samples of sorghum collection had an average variability according to the traits ‘leaf length’ (V = 15.3%) and ‘leaf width’ (V = 11.8%), and were stable according to the trait ‘number of leaves per plant’ (V = 7.4%). Correlation and regression analysis has shown that ‘leaf length’ had an average inverse correlation with air temperature (r = –0.42±0.06) and a strong direct correlation with precipitation (r = 0.78±0.05). The trait ‘leaf width’ is practically independent of weather conditions. The number of leaves had an average negative correlation with air temperature (r = –0.55±0.06), and a weak correlation with amount of precipitation. A leaf length and width are marker indicators of high productivity, so they can be used in plant selection for productivity.

Bio-fertilizers are in the present more and more of interest as alternative nutritive inputs. This research aim was to test different doses of yeast and caffeine on pepper growth and chlorophyll content. The experiment in controlled conditions consisted of 8 phytocosms treatments with 3 yeast and caffeine doses 1%, 2%, and 3%, one mixed treatment (2%), and the control treatment in five replications. The yeast addition promoted all the tested morphological parameters especially the middle dose tested. Caffeine treatments induced a slow growth of pepper vegetative period, even a delayed development compared with the control treatment. In conclusion, the mixed treatment was the most efficient pepper bio-fertilizer and provided the highest values of leaf length, width, seedling height, and also total chlorophyll content. [ABSTRACT FROM AUTHOR]

Leaf shape and size can vary between hybrids and their parents. However, this has seldom been quantitatively tested. Photinia × fraseri is an important landscaping plant in East Asia as a hybrid between evergreen shrubs P. glabra and P. serratifolia. Its leaf shape looks like that of P. serratifolia. To investigate leaf shape, we used a general equation for calculating the leaf area (A) of broad-leaved plants, which assumes a proportional relationship between A and product of lamina length (L) and width (W). The proportionality coefficient (which is referred to as the Montgomery parameter) serves as a quantitative indicator of leaf shape, because it reflects the proportion of leaf area A to the area of a rectangle with L and W as its side lengths. The ratio of L to W, and the ellipticalness index were also used to quantify the complexity of leaf shape for elliptical leaves. A total of >4000 leaves from P. × fraseri and P. serratifolia (with >2000 leaves for each taxon) collected on a monthly basis was used to examine: (i) whether there is a significant difference in leaf shape between the two taxa, and (ii) whether there is a monotonic or parabolic trend in leaf shape across leaf ages. There was a significant difference in leaf shape between the two taxa (p < 0.05). Although there were significant differences in leaf shape on a monthly basis, the variation in leaf shape over time was not large, i.e., leaf shape was relatively stable over time for both taxa. However, the leaf shape of the hybrid was significantly different from its parent P. serratifolia, which has wider and more elliptical leaves than the hybrid. This work demonstrates that variations in leaf shape resulting from hybridization can be rigorously quantified and compared among species and their hybrids. In addition, this work shows that leaf shape does not changes as a function of age either before or after the full expansion of the lamina. [ABSTRACT FROM AUTHOR]

Abstract Background Leaf length and width could be a functioning relationship naturally as plant designs. Single-vein leaves have the simplest symmetrical distribution and structural design, which means that fast-growing single-vein species could interpret the scheme more efficiently. The distribution of leaf length and width can be modulated for better adaptation, providing an informative perspective on the various operational strategies in an emergency, while this mechanism is less clear. Here we selected six age groups of Cunninghamia lanceolata pure forests, including saplings, juveniles, mature, and old-growth trees. We pioneered a tapering model to describe half-leaf symmetric distribution with mathematical approximation based on every measured leaf along developmental sequence, and evaluated the ratio of leaf basal part length to total length (called tipping leaf length ratio). Results The tipping leaf length ratio varied among different tree ages. That means the changes of tipping leaf length ratio and leaf shape are a significant but less-noticed reflection of trees tradeoff strategies at different growth stages. For instance, there exhibited relatively low ratio during sapling and juvenile, then increased with increasing age, showing the highest value in their maturity, and finally decreased on mature to old-growth transition. The tipping leaf length ratio serves as a cost-benefit ratio, thus the subtle changes in the leaf symmetrical distribution within individuals reveal buffering strategy, indicating the selection for efficient design of growth and hydraulic in their developmental sequences. Conclusions Our model provides a physical explanation of varied signatures for tree operations in hydraulic buffering through growth stages, and the buffering strategy revealed from leaf distribution morphologically provides evidence on the regulation mechanism of leaf biomechanics, hydraulics and physiologies. Our insight contributes greatly to plant trait modeling, policy and management, and will be of interest to some scientists and policy makers who are involved in climate change, ecology and environment protection, as well as forest ecology and management.

Purpose: Whole‐brain radiotherapy (WBRT) is commonly used in patients with multiple brain metastases. Compared with conventional WBRT, hippocampal avoidance WBRT (HA‐WBRT) more favorably preserves cognitive function and the quality of life. The hippocampal volume is considerably small (approximately 3.3 cm3). Therefore, downsizing the leaf width of a multileaf collimator (MLC) may provide higher spatial resolution and better plan quality. Volumetric modulated arc therapy (VMAT) could simulate the half MLC leaf width through couch shifting between arcs. This study investigated changes in VMAT quality for HA‐WBRT with a simulated fine MLC leaf width. Methods: We included 18 patients with brain metastasis. All target and avoidance structures were contoured by an experienced radiation oncologist. The prescribed dose was 30 Gy in 10 fractions. For each patient, three different treatment plans were generated for comparison: VMAT with couch‐shift, VMAT without couch‐shift, and TomoTherapy. All treatment plans fulfilled Radiation Therapy Oncology Group (RTOG) 0933 criteria for HA‐WBRT. The Wilcoxon paired signed‐rank test was used to compare different treatment plans. Results: VMAT with couch‐shift had the better average conformity index (0.823) with statistically significant difference compared to VMAT without couch‐shift (0.810). VMAT with couch‐shift (0.219) had a more favorable average homogeneity index (HI) than did VMAT without couch‐shift (0.230), although the difference was not significant. TomoTherapy had an optimal average HI of 0.070. In terms of the hippocampus, all three treatment plans met the RTOG 0933 criteria. VMAT with couch‐shift had a lower average Dmax (15.2 Gy) than did VMAT without couch‐shift (15.3 Gy, p = 0.071) and TomoTherapy (15.5 Gy, p = 0.133). The average D100% of hippocampus was the same for both VMAT with and without couch‐shift (8.5 Gy); however, TomoTherapy had a lower average D100% value of 7.9 Gy. The treatment delivery time was similar between VMAT with and without couch‐shift (average, 375.0 and 369.6 s, respectively). TomoTherapy required a long average delivery time of 1489.9 s. Conclusion: The plan quality of VMAT for HA‐WBRT was improved by using the couch‐shift technique to simulate the half MLC leaf width. However, the improvement was not statistically significant except conformity index. The downsizing effect decreased with the use of the sophisticated grade of VMAT. TomoTherapy offered superior plan quality but required the longest delivery time. [ABSTRACT FROM AUTHOR]

Shoot morphology in rice plants changes in response to P deficiency. However, how genotypic variations in these morphological changes affect the canopy development and biomass production have hardly been explored. The study aimed to identify specific shoot morphological traits that confer biomass production under P deficiency. Four rice genotypes, including AZ-97 (WAS 63–22-5-9-10-1), which exhibits high performance under highly P-deficient fields in Madagascar, were grown for 56 days in flooded pots over several P application rates to simulate P-sufficient and moderately, severely, and extremely P-deficient conditions. AZ-97 had superior shoot P contents and biomass than Takanari, a high-yielding cultivar, and X265, a common high-yielding cultivar in Madagascar at severely to moderately P-deficient conditions. Shoot biomass was highly correlated with projected leaf area (PLA) from the early growth stage, and tiller number, leaf width, and leaf elongation rate explained the variations in PLA. These morphological traits reduced significantly with decreased P application rates, while reduction in AZ-97 was small relative to the other genotypes, even for equivalent shoot P contents. As the result, AZ-97 had greater PLA per unit of shoot P content at equivalent shoot P contents. The result indicates that lower sensitivity and degrees of change in shoot morphology when exposed to P deficiency stress could be a key trait facilitating the maintenance of captured radiation and subsequently influencing genotypic differences in external P uptakes and biomass production. AZ-97 is a potential donor with such traits that can offer an additional avenue for genetic improvement toward P-efficient rice production.Abbreviations DAT: days after transplanting; LN: leaf number in the main stem; PLA: projected green leaf area; PUE: phosphorus use efficiency; SSA: Sub-Saharan Africa.

Background and Aims Leaf size has considerable ecological relevance, making it desirable to obtain leaf size estimations for as many species worldwide as possible. Current global databases, such as TRY, contain leaf size data for ~30 000 species, which is only ~8% of known species worldwide. Yet, taxonomic descriptions exist for the large majority of the remainder. Here we propose a simple method to exploit information on leaf length, width and shape from species descriptions to robustly estimate leaf areas, thus closing this considerable knowledge gap for this important plant functional trait. Methods Using a global dataset of all major leaf shapes measured on 3125 leaves from 780 taxa, we quantified scaling functions that estimate leaf size as a product of leaf length, width and a leaf shape-specific correction factor. We validated our method by comparing leaf size estimates with those obtained from image recognition software and compared our approach with the widely used correction factor of 2/3. Key Results Correction factors ranged from 0.39 for highly dissected, lobed leaves to 0.79 for oblate leaves. Leaf size estimation using leaf shape-specific correction factors was more accurate and precise than estimates obtained from the correction factor of 2/3. Conclusion Our method presents a tractable solution to accurately estimate leaf size when only information on leaf length, width and shape is available or when labour and time constraints prevent usage of image recognition software. We see promise in applying our method to data from species descriptions (including from fossils), databases, field work and on herbarium vouchers, especially when non-destructive in situ measurements are needed. [ABSTRACT FROM AUTHOR]

Summary: Leaf width (LW) is an important component of plant architecture that extensively affects both light capture during photosynthesis and grain yield, particularly under dense planting conditions. However, the genetic and molecular mechanisms regulating LW remain largely elusive in maize (Zea mays L.). In this study, qLW4a, a major quantitative trait locus controlling LW, was identified in a population constructed with maize inbred lines PH6WC, with wide leaves, and Lin387, with narrow leaves. Map‐based cloning revealed that ZmNL4, a kelch‐repeat superfamily gene, emerged to be the candidate for qLW4a, and a single‐base deletion in the conserved SMC_prok_B domain of ZmNL4 in Lin387 caused a frame shift, leading to premature termination. Consistently, the knockout of ZmNL4 by CRISPR/Cas9 editing significantly reduced the LW, which was attributed to a reduction in the cell number instead of cell size, indicating a role of ZmNL4 in regulating cell division. Transcriptomic comparison of ZmNL4 knockout lines with the wild type B73‐329 revealed that ZmNL4 might participate in cell wall biogenesis, asymmetric cell division, metabolic processes, transmembrane transport and response to external stimulus, etc. These results provide insights into the genetic and molecular mechanisms of ZmNL4 in controlling LW and could potentially contribute to optimizing plant architecture for maize breeding. [ABSTRACT FROM AUTHOR]

Background Morphological leaf traits are frequently used to quantify, understand and predict plant and vegetation functional diversity and ecology, including environmental and climate change responses. Although morphological leaf traits are easy to measure, their coverage for characterising variation within species and across temporal scales is limited. At the same time, there are about 3100 herbaria worldwide, containing approximately 390 million plant specimens dating from the 16th to 21st century, which can potentially be used to extract morphological leaf traits. Globally, plant specimens are rapidly being digitised and images are made openly available via various biodiversity data platforms, such as iDigBio and GBIF. Based on a pilot study to identify the availability and appropriateness of herbarium specimen images for comprehensive trait data extraction, we developed a spatio-temporal dataset on intraspecific trait variability containing 128,036 morphological leaf trait measurements for seven selected species. [ABSTRACT FROM AUTHOR]

In Ecuador, the favorable climatic and ecological conditions allow small, médium and large producers to dedícate themselves to the exploitation of bananas and plantains. Inthe case of the orito, it is a special fruit, of great acceptance for its flavor and aroma. The plantations are found as monocultures in some cases and in others, as associations that are interspersed with different fruit species and timber trees. The different banana species reproduce asexually from vegetative fractions. On the other hand, the use of organic fertilizers is due to the fact that they are a source of bacterial life for the soil and are necessary for the nutrition of plants. They are obtained from the degradation and mineralization of organic materials (manure, kitchen waste, etc.). The different types of bioles are prepared with different manures that must be fermented for two to three months in a plástic container, it is a fertilizer that allows to replace a large part of chemical fertilizers. With this background, the present investigation aimed to evalúate the effect of two liquid organic fertilizers (worm manure liquid based on cow dung (HLV) and beef manure tea (TEV) at a concentration of 75% on the development of corms of orito (Musa acuminata AA) to obtain plants in a fast way and establish cash crops for the conditions of Cantón Cumandá province of Chimborazo The trial was conducted in a randomized blocks design with 3 treatments and 3 repetitions. root mass in g (PMR), root volume in mi (VR), root length in cm (LR), leaf length in cm (LH), foliage weight in g (PF) and leaf width in cm (AH) Every 14 days, evaluations were made from 111 days to 181 days for the development of the corms The variables evaluated did not show significant differences until 167 days. in the PMR, VR, PF, LH and AH, while the LR did not show significant differences. The best response was obtained with the HLV, which surpassed the TEV and the control (T). The outstanding valúes were found at 181 days for: PMR with 110.6 g, VR 110 ml, PF 205 g, LH 36 cm, AH 15.5 cm, LR 59.5 cm. do not show significance with the other treatments.

Leaf shape and size can vary between hybrids and their parents. However, this has seldom been quantitatively tested. Photinia × fraseri is an important landscaping plant in East Asia as a hybrid between evergreen shrubs P. glabra and P. serratifolia. Its leaf shape looks like that of P. serratifolia. To investigate leaf shape, we used a general equation for calculating the leaf area (A) of broad-leaved plants, which assumes a proportional relationship between A and product of lamina length (L) and width (W). The proportionality coefficient (which is referred to as the Montgomery parameter) serves as a quantitative indicator of leaf shape, because it reflects the proportion of leaf area A to the area of a rectangle with L and W as its side lengths. The ratio of L to W, and the ellipticalness index were also used to quantify the complexity of leaf shape for elliptical leaves. A total of >4000 leaves from P. × fraseri and P. serratifolia (with >2000 leaves for each taxon) collected on a monthly basis was used to examine: (i) whether there is a significant difference in leaf shape between the two taxa, and (ii) whether there is a monotonic or parabolic trend in leaf shape across leaf ages. There was a significant difference in leaf shape between the two taxa (p < 0.05). Although there were significant differences in leaf shape on a monthly basis, the variation in leaf shape over time was not large, i.e., leaf shape was relatively stable over time for both taxa. However, the leaf shape of the hybrid was significantly different from its parent P. serratifolia, which has wider and more elliptical leaves than the hybrid. This work demonstrates that variations in leaf shape resulting from hybridization can be rigorously quantified and compared among species and their hybrids. In addition, this work shows that leaf shape does not changes as a function of age either before or after the full expansion of the lamina.

Background: Leaf length and width could be a functioning relationship naturally as plant designs. Single-vein leaves have the simplest symmetrical distribution and structural design, which means that fast-growing single-vein species could interpret the scheme more efficiently. The distribution of leaf length and width can be modulated for better adaptation, providing an informative perspective on the various operational strategies in an emergency, while this mechanism is less clear. Here we selected six age groups of Cunninghamia lanceolata pure forests, including saplings, juveniles, mature, and old-growth trees. We pioneered a tapering model to describe half-leaf symmetric distribution with mathematical approximation based on every measured leaf along developmental sequence, and evaluated the ratio of leaf basal part length to total length (called tipping leaf length ratio). Results: The tipping leaf length ratio varied among different tree ages. That means the changes of tipping leaf length ratio and leaf shape are a significant but less-noticed reflection of trees tradeoff strategies at different growth stages. For instance, there exhibited relatively low ratio during sapling and juvenile, then increased with increasing age, showing the highest value in their maturity, and finally decreased on mature to old-growth transition. The tipping leaf length ratio serves as a cost-benefit ratio, thus the subtle changes in the leaf symmetrical distribution within individuals reveal buffering strategy, indicating the selection for efficient design of growth and hydraulic in their developmental sequences. Conclusions: Our model provides a physical explanation of varied signatures for tree operations in hydraulic buffering through growth stages, and the buffering strategy revealed from leaf distribution morphologically provides evidence on the regulation mechanism of leaf biomechanics, hydraulics and physiologies. Our insight contributes greatly to plant trait modeling, policy and management, and will be of interest to some scientists and policy makers who are involved in climate change, ecology and environment protection, as well as forest ecology and management. [ABSTRACT FROM AUTHOR]

Invasive species represent excellent opportunities to study the evolutionary potential of traits important to success in novel environments. Although some ecologically important traits have been identified in invasive species, little is typically known about the genetic mechanisms that underlie invasion success in non-model species. Here, we use a genome-wide association (GWAS) approach to identify the genetic basis of trait variation in the non-model, invasive, diffuse knapweed [Centaurea diffusa Lam. (Asteraceae)]. To assist with this analysis, we have assembled the first draft genome reference and fully annotated plastome assembly for this species, and one of the first from this large, weedy, genus, which is of major ecological and economic importance. We collected phenotype data from 372 individuals from four native and four invasive populations of C. diffusa grown in a common environment. Using these individuals, we produced reduced-representation genotype-by-sequencing (GBS) libraries and identified 7,058 SNPs. We identify two SNPs associated with leaf width in these populations, a trait which significantly varies between native and invasive populations. In this rosette forming species, increased leaf width is a major component of increased biomass, a common trait in invasive plants correlated with increased fitness. Finally, we use annotations from Arabidopsis thaliana to identify 98 candidate genes that are near the associated SNPs and highlight several good candidates for leaf width variation.

Shoot morphology in rice plants changes in response to P deficiency. However, how genotypic variations in these morphological changes affect the canopy development and biomass production have hardly been explored. The study aimed to identify specific shoot morphological traits that confer biomass production under P deficiency. Four rice genotypes, including AZ-97 (WAS 63–22-5-9-10-1), which exhibits high performance under highly P-deficient fields in Madagascar, were grown for 56 days in flooded pots over several P application rates to simulate P-sufficient and moderately, severely, and extremely P-deficient conditions. AZ-97 had superior shoot P contents and biomass than Takanari, a high-yielding cultivar, and X265, a common high-yielding cultivar in Madagascar at severely to moderately P-deficient conditions. Shoot biomass was highly correlated with projected leaf area (PLA) from the early growth stage, and tiller number, leaf width, and leaf elongation rate explained the variations in PLA. These morphological traits reduced significantly with decreased P application rates, while reduction in AZ-97 was small relative to the other genotypes, even for equivalent shoot P contents. As the result, AZ-97 had greater PLA per unit of shoot P content at equivalent shoot P contents. The result indicates that lower sensitivity and degrees of change in shoot morphology when exposed to P deficiency stress could be a key trait facilitating the maintenance of captured radiation and subsequently influencing genotypic differences in external P uptakes and biomass production. AZ-97 is a potential donor with such traits that can offer an additional avenue for genetic improvement toward P-efficient rice production.Abbreviations DAT: days after transplanting; LN: leaf number in the main stem; PLA: projected green leaf area; PUE: phosphorus use efficiency; SSA: Sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Although plant organ shapes are defined by spatio-temporal variations of directional tissue expansion, this is a little characterized aspect of organ growth regulation. Although it is well known that the plant hormone gibberellin increases the leaf length/with ratio, its effects on cell expansion in the growing leaf are largely unknown. To understand how variations in rate and anisotropy of growth establish the typical monocotelydonous leaf shape, we studied the leaf growth zone of maize (Zea mays) with a kinematic analysis of cell expansion in the three directions of growth: proximo-distal, medio-lateral, and dorso-ventral. To determine the effect of gibberellin, we compared a gibberellin-deficient dwarf3 mutant and the overproducing UBI::GA20OX-1 line with their wild types. We found that, as expected, longitudinal growth was dominant throughout the growth zone. The highest degree of anisotropy occurred in the division zone, where relative growth rates in width and thickness were almost zero. Growth anisotropy was smaller in the elongation zone, due to higher lateral and dorso-ventral growth rates. Growth in all directions stopped at the same position. Gibberellin increased the size of the growth zone and the degree of growth anisotropy by stimulating longitudinal growth rates. Inversely, the duration of expansion was negatively affected, so that mature cell length was unaffected, while width and height of cells were reduced. Our study provides a detailed insight in the dynamics of growth anisotropy in the maize leaf and demonstrates that gibberellin specifically stimulates longitudinal growth rates throughout the growth zone.

We aimed to propose a reliable and accurate model using non-destructive measurements of leaf length (L) and/or width (W) for estimating leaf area (LA) of three genotypes of purging nut (Jatropha curcas L.), i.e. Astrea and Barranca, both Colombian and a Mexican genotype. For model construction, ~500 healthy leaves were collected from at least 20 healthy plants naturally grown at each locations, and encompassed the full spectrum of measurable leaf sizes. Equations with L and/or W were generated; however, the best fit were made when product between L and W (LW). To validate these models, independent data set of 450 leaves were used. Thus, we developed a single model (Yi = β0 * LWβ1) with high precision and accuracy, random dispersion pattern of residuals and unbiased. In spite of this, a single equation, joining all the studied genotypes, was developed [LA = 0.822 * (LW)0.983; standard errors: β0 = 0.020, β1 = 0.004; R2a = 0.976], which greatly simplifies the process of measuring the leaf area of the genotypes, a fact that should be highlighted.

Premise: The nondestructive measurement of leaf area is important for expediting data acquisition in the field. The Montgomery equation (ME) assumes that leaf area (A) is a proportional function of the product of leaf length (L) and width (W), i.e., A = cLW, where c is called the Montgomery parameter. The ME has been successfully applied to calculate the surface area of many broad‐leaved species with simple leaf shapes. However, whether this equation is valid for more complex leaf shapes has not been verified. Methods: Leaf A, L, and W were measured directly for each of 5601 leaves of 15 vine species, and ME and three other models were used to fit the data. All four models were compared based on their root mean square errors (RMSEs) to determine whether ME provided the best fit. Results: The ME was a reliable method for estimating the A of all 15 species. In addition, the numerical values of 13 of the 15 values of c fell within a previously predicted numerical range (i.e., between 1/2 and π/4). The data show that the numerical values of c are largely affected by the value of W/L, the concavity of the leaf base, and the number of lobes on the lamina. Conclusions: The Montgomery parameter can reflect the influence of leaf shape on leaf‐area calculations and can serve as an important tool for nondestructive measurements of leaf area for many broad‐leaved species and for the investigation of leaf morphology. [ABSTRACT FROM AUTHOR]

Although plant organ shapes are defined by spatio-temporal variations of directional tissue expansion, this is a little characterized aspect of organ growth regulation. Although it is well known that the plant hormone gibberellin increases the leaf length/with ratio, its effects on cell expansion in the growing leaf are largely unknown. To understand how variations in rate and anisotropy of growth establish the typical monocotelydonous leaf shape, we studied the leaf growth zone of maize (Zea mays) with a kinematic analysis of cell expansion in the three directions of growth: proximo-distal, medio-lateral, and dorso-ventral. To determine the effect of gibberellin, we compared a gibberellin-deficient dwarf3 mutant and the overproducing UBI::GA20OX-1 line with their wild types. We found that, as expected, longitudinal growth was dominant throughout the growth zone. The highest degree of anisotropy occurred in the division zone, where relative growth rates in width and thickness were almost zero. Growth anisotropy was smaller in the elongation zone, due to higher lateral and dorso-ventral growth rates. Growth in all directions stopped at the same position. Gibberellin increased the size of the growth zone and the degree of growth anisotropy by stimulating longitudinal growth rates. Inversely, the duration of expansion was negatively affected, so that mature cell length was unaffected, while width and height of cells were reduced. Our study provides a detailed insight in the dynamics of growth anisotropy in the maize leaf and demonstrates that gibberellin specifically stimulates longitudinal growth rates throughout the growth zone. [ABSTRACT FROM AUTHOR]

Introduction: Light stress is an important factor limiting the biomass yield while combining forage production with crops or forestry. Guinea grass is a widely adapted perennial fodder grass. The species exhibits high degree of variation for morphology, adaptation and biomass yield. Objective: Since there is a need in identifying shade adapted forage grasses for the expanding area under agroforestry/silvipastures, the present investigation took the task of understanding how the morphologically distinct genotypes of guinea grass respond under different shaded intensities. Methods: In the present study, forty-four genotypes related with the shade response were studied in varying shading conditions (pure sunlight, 25, 50 and 75 % shade) created artificially. Results: Based on green and dry matter yields ranking, the genotype IG 01-98 performed the best followed by genotypes IG 01-92, IG 97-5, IG 97-6 and IG 01-89 in decreasing order. Particularly, IG 01-93 was identified as the best performing under 50 % shading conditions. On the other hand, most of the top ranking genotypes performed well both under open and up to 50 % of shade. Morphologically, these genotypes were taller and possessed longer and broader leaves. Under shaded conditions (over 50 %), leaf length and width showed an increasing trend compared to open conditions. Also, chlorophyll content increased with shading intensity. Conclusions: Most of the genotypes collected from the southern Indian humid tropical environment with early flowering nature were tolerant to shade. Differential genotypic response was observed for biomass yield and yield attributes under shade. The study established appreciable variability for shade tolerance among genotypes. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT 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.)

Receptor-like kinases (RLKs) are important for plant growth, development and defense responses. The S-receptor protein kinases (SRKs), which represent an RLK subfamily, control the self- incompatibility among Brassica species. However, little information is available regarding SRK functions in rice. We identified a gene OsSRK1 encoding an atypical SRK. The transcript of OsSRK1 was induced by abscisic acid (ABA), salt and polyethylene glycol. OsSRK1 localized to the plasma membrane and cytoplasm. Leaf width was increased in OsSRK1 -overexpression (OsSRK1 -OX) transgenic rice plants, likely because of an increase in cell number per leaf. Furthermore, the expression levels of OsCYCA3-1 and OsCYCD2-1, which encode positive regulators of cell division, were up-regulated in leaf primordium of OsSRK1 -OX rice plants relative to those in wild type. Meanwhile, the expression level of OsKRP1 , which encodes cell cycle inhibitor, was down-regulated in the OsSRK1 -OX plants. Therefore, it is deduced that OsSRK1 regulates leaf width by promoting cell division in the leaf primordium. Additionally, Os SRK1 -OX plants exhibited enhanced ABA sensitivity and salt tolerance compared with wild type. These results suggest that OsSRK1 plays important roles in leaf development and salt responses in rice. [ABSTRACT FROM AUTHOR]

Many plant species produce ovate leaves, but there is no general parametric model for describing this shape. Here, we used two empirical nonlinear equations, the beta and Lobry–Rosso–Flandrois (LRF) equations, and their modified forms (referred to as the Mbeta and MLRF equations for convenience), to generate bilaterally symmetrical curves along the x-axis to form ovate leaf shapes. In order to evaluate which of these four equations best describes the ovate leaf shape, we used 14 leaves from 7 Neocinnamomum species (Lauraceae) and 72 leaves from Chimonanthus praecox (Calycanthaceae). Using the AIC and adjusted root mean square error to compare the fitted results, the modified equations fitted the leaf shapes better than the unmodified equations. However, the MLRF equation provided the best overall fit. As the parameters of the MLRF equation represent leaf length, maximum leaf width, and the distance from leaf apex to the point associated with the maximum leaf width along the leaf length axis, these findings are potentially valuable for studying the influence of environmental factors on leaf shape, differences in leaf shape among closely related plant species with ovate leaf shapes, and the extent to which leaves are bilaterally symmetrical. This is the first work in which temperature-dependent developmental equations to describe the ovate leaf shape have been employed, as previous studies lacked similar leaf shape models. In addition, prior work seldom attempted to describe real ovate leaf shapes. Our work bridges the gap between theoretical leaf shape models and empirical leaf shape indices that cannot predict leaf shape profiles.

Introduction: Spinach is an important leafy vegetable in the cold season, and despite the fact that is considered as low-calorie food source contains significant amount of minerals such as iron, and vitamin A and C. According to the University of Utah 3.8 dS m-1 is salinity tolerance threshold for the spinach and yield decrease that have been reported by 10%, 25% and 50% at 5.5, 7 and 8 dS m-1 salinity. The necessity to supply adequate potassium has been demonstrated in salinity conditions. In salt stress conditions, foliar application of K in spinach, reduces the harmful effects of salt and increase the ratio of potassium to sodium (1.61 to 2.72). Foliar application of K with prevent of potassium transfer from root to shoot is causing continuation of photosynthesis and reduce the effects of salinity. Absorption of potassium from the leaves depends on the type of used compound. In this context, characteristics of plant (leaves with a waxy composition, duration of growth and leaf area) are important. 100 kg ha-1 of potassium in salt stress conditions by reducing the absorption of sodium, increased salt tolerance on the sunflower. Materials and Methods: In order to evaluate the foliar application of K on the yield and yield components of spinach in salt stress condition, a study was conducted in 2012 by using split plot randomized based on complete block design with four replications at Isfahan Agricultural and Natural Resources Research Station. Three levels of irrigation water salinity consisted of a control (2 dS m-1), well water with salinity (4 dS m-1) and well water with salinity (8dS m-1) arranged in main plots and two levels of control and foliar applications of potassium fertilizer containing potassium oxide solubility in water (2.5 ml per liter) arranged in subplots. Statistical analysis was conducted by using SAS software and statistical tests were compared with Duncan at 5 percent. Result and Discussions: The results showed that the yield of spinach with foliar application of K and 4 dS m-1 salinity was equaled 35300 kg ha-1 which had not significantly different from control treatment. Foliar application of K and 8 dS m-1 salinity, and also 8 dS m-1 salinity and without foliar potassium, had 20.2 and 38% yield reduction, respectively. In salinity 2.1, 4 and 8 dS m-1 plants m-2 were 40, 38.1 and 29.1, respectively. Leaf dry matter percent was improved with foliar application of K in 8 dS m-1 salinity. Effect of potassium, as modulators of salt in spinach, by researches of Shannon and Greve (24) and Kaya et al (14) have also been emphasized. Spinach leaves number was from 11.4 to 16.7 in different treatments. Foliar application of K in 4 and 8 dS m-1 salt treatment was increase in the number of leaves. This increased in treatment of 4 and 8 dS m-1 was 15.3 and 28.9 percent, respectively. In both saline treatments of 4 and 8 dS m-1, leaf length was positively affected by the application of potassium but in salinity 4 dS m-1 (unlike the eight salinity dS m-1) leaf width was not affected by the potassium spraying. The ability of plants to maintain intracellular potassium to sodium ratio leaves in certain extent is necessary for a salt tolerance. In fact, the application of potassium in salinity conditions by increasing the concentration of the K in organs is a kind of acclimation to the salt stress and activates repair mechanisms of the damage against of stress agent. The length of tail leaves in 4 dS m-1 salt was not significantly affected by the spraying of potassium while in 8 dS m-1 salinity, spraying potassium led to an increase of 28 percent in length of leaf tail. The effect of K application on the dry matter content in the 8 dS m-1 salinity was statistically significant. Potassium is the most abundant cation-forming in many plants (typically more than 10% of dry weight) and less than 10 grams per kg-1 of dry weight appear deficiency symptoms in most plants. Conclusion: According to the results, in salinity conditions, the foliar application of K can be used as a factor to reduce the harmful effects of salinity. While the lack of fresh water for irrigation in arid and semi-arid crops has become a challenge, attention to the moderated mechanisms of the harmful effects of salt, is one of the approaches to face the challenges ahead.

Introduction: This study explores the feasibility of SRS/SRT treatment with MLC leaves wider than 2.5 mm at isocenter by inter-comparing treatment plans produced with 2.5, 5.0, and 10.0 mm leaves for various target sizes and shapes.Materials and methods: Forty previously treated patients were re-planned using 2.5, 5.0, and 10.0 mm wide MLC leaves. For each patient, all three plans were evaluated and contrasted between them in terms of five metrics: target dose homogeneity, conformity index, organs at risk dose, dose fall off outside the target, and dose to normal tissues. A regularity index RI was introduced that quantified the degree of target shape irregularity. The effect of target size and shape irregularity on feasibility of 5.0 and 10.0 mm leaves was analyzed.Results: Consistent plan degradation was observed for 10.0 mm (sometimes for 5.0 mm) compared to 2.5 mm MLC in terms of the above five plan metrics, but this degradation was small to clinically insignificant. As an exception, when target (PTV) size was smaller than about 1 cm diameter, clinically significant differences were found between 2.5, 5.0, and 10.0 mm MLC.Conclusion: 5.0 and 10.0 mm MLC can be used in SRS/SRT for targets (PTV) diameter larger than 1 cm. For smaller targets, 2.5 mm MLC is clinically superior, 5.0 is acceptable and 10.0 mm MLC is discouraged in terms of PTV dose conformity.

A model for estimating the area of individual leaves (LA) by employing their dimensions was developed for chrysanthemum. Further hypotheses were tested: (a) LA estimation is improved by considering blade length (Lb) rather than leaf length (L), and (b) a reasonable LA estimation can be attainable by considering L in conjunction to a shape trait, which is cultivar dependent. For the model development, six cultivars were employed (1500 leaves in total), while for model validation, an independent set of nine cultivars was utilized (1125 leaves in total). Several characteristics were digitally assessed in fully expanded leaves which included petiole length, leaf L, width (W), perimeter, shape traits (aspect ratio, circularity, roundness, solidity), together with LA. LA estimation was more accurate by considering both L and W, as compared to a single dimension. A linear model, employing the product of L by W as independent variable, provided the most accurate LA estimation (R2 = 0.84). The model validation indicated a highly significant correlation between computed and measured LA (R2 = 0.88). Replacing L by Lb reasonably predicted LA (R2 = 0.832) but at some expense of accuracy. Contrary to expectation, considering L (or W) and a cultivar-specific shape trait generally led to poor LA estimations.

Introduction: This study explores the feasibility of SRS/SRT treatment with MLC leaves wider than 2.5 mm at isocenter by inter-comparing treatment plans produced with 2.5, 5.0, and 10.0 mm leaves for various target sizes and shapes. Materials and methods: Forty previously treated patients were re-planned using 2.5, 5.0, and 10.0 mm wide MLC leaves. For each patient, all three plans were evaluated and contrasted between them in terms of five metrics: target dose homogeneity, conformity index, organs at risk dose, dose fall off outside the target, and dose to normal tissues. A regularity index RI was introduced that quantified the degree of target shape irregularity. The effect of target size and shape irregularity on feasibility of 5.0 and 10.0 mm leaves was analyzed. Results: Consistent plan degradation was observed for 10.0 mm (sometimes for 5.0 mm) compared to 2.5 mm MLC in terms of the above five plan metrics, but this degradation was small to clinically insignificant. As an exception, when target (PTV) size was smaller than about 1 cm diameter, clinically significant differences were found between 2.5, 5.0, and 10.0 mm MLC. Conclusion: 5.0 and 10.0 mm MLC can be used in SRS/SRT for targets (PTV) diameter larger than 1 cm. For smaller targets, 2.5 mm MLC is clinically superior, 5.0 is acceptable and 10.0 mm MLC is discouraged in terms of PTV dose conformity. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the contribution of penumbra in the improvement of healthy tissue sparing at reduced source‐to‐axis distance (SAD) for simple spherical target and different prescription isodoses (PI). Method: A TPS‐independent method was used to estimate three‐dimensional (3D) dose distribution for stereotactic treatment of spherical targets of 0.5 cm radius based on single beam two‐dimensional (2D) film dosimetry measurements. 1 cm target constitutes the worst case for the conformation with standard Multi‐Leaf Collimator (MLC) with 0.5 cm leaf width. The measured 2D transverse dose cross‐sections and the profiles in leaf and jaw directions were used to calculate radial dose distribution from isotropic beam arrangement, for both quadratic and circular beam openings, respectively. The results were compared for standard (100 cm) and reduced SAD 70 and 55 cm for different PI. Results: For practical reduction of SAD using quadratic openings, the improvement of healthy tissue sparing (HTS) at distances up to 3 times the PTV radius was at least 6%–12%; gradient indices (GI) were reduced by 3–39% for PI between 40% and 90%. Except for PI of 80% and 90%, quadratic apertures at SAD 70 cm improved the HTS by up to 20% compared to circular openings at 100 cm or were at least equivalent; GI were 3%–33% lower for reduced SAD in the PI range 40%–70%. For PI = 80% and 90% the results depend on the circular collimator model. Conclusion: Stereotactic treatments of spherical targets delivered at reduced SAD of 70 or 55 cm using MLC spare healthy tissue around the target at least as good as treatments at SAD 100 cm using circular collimators. The steeper beam penumbra at reduced SAD seems to be as important as perfect target conformity. The authors argue therefore that the beam penumbra width should be addressed in the stereotactic studies. [ABSTRACT FROM AUTHOR]

Leaf area is among the most important leaf functional traits, and it determines leaf temperature and alters light harvesting. The calculation of individual leaf area is the basis of calculating the leaf area index (i.e., the total leaf area per unit ground area) that is directly associated with the ability of plants to intercept light for photosynthesis. It is valuable to provide a fast and reliable approach to measuring leaf area. Here, we examined the validity and calculation accuracy of the Montgomery equation (ME), which describes the area of a leaf as a product of leaf length, width and a specific coefficient referred to as the Montgomery parameter, MP. Using ME, we calculated leaf areas of different age groups of bamboo culms. For most broad-leaved plants, leaf area is proportional to the product of leaf length and width, and MP falls within a range of 1/2 to π/4, depending on leaf shape. However, it is unknown whether there is an intra-specific variation in MP resulting from age structure and whether such a variation can significantly reduce the predictability of ME in calculating leaf area. This is relevant as a population of perennial plants usually composes of different age groups. We used Moso bamboos as model as this species is of ecological and economic importance in southern China, and pure stands can cover six to seven plant age groups. We used five age groups of moso bamboo and sampled 260–380 leaves for each group to test whether ME holds true for each group and all groups combined, whether there are significant differences in MP among different age groups, and whether the differences in MP can lead to large prediction errors for leaf area. We observed that for each age group and all groups combined, there were significant proportional relationships between leaf area and the product of leaf length and width. There were small but significant differences in MP among the five age groups (MP values ranged from 0.6738 to 0.7116 for individual plant ages; MP = 0.6936 for all age groups combined), which can be accounted for by the minor intergroup variation of leaf shape (reflected by the leaf width/length ratio). For all age classes, MP estimated for the pooled data resulted in

The use of warm season turfgrasses is a consolidated trend in the climatic transition zone of Mediterranean countries, in particular St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) begins to be widespread in warm coastal areas. However, little is known about the performance of the different cultivars of this species in southern Europe. In 2016-2017 a trial was carried out in three locations in Italy, Padova, Pisa, and Palermo, located in the north, center and south of the country respectively. Four cultivars (Floratine, Captiva, Sapphire, Palmetto) and five ecotypes (CeRTES 201, CeRTES 202, CeRTES 203, CeRTES 204, CeRTES 205) were compared in terms of their growth characteristics and morphological traits during establishment. The results highlighted that stolon growth was significantly affected by the location, as well as green colour retention. Stolon growth rate, internode length and internode volume and turf quality were, however, significantly determined by the accession effect. The quality of the ecotypes was also in some cases comparable to that of the cultivars. In Padova, winterkill occurred in most of the accessions, while in Pisa and Palermo, all the entries survived. In conclusion, St. Augustinegrass is suitable for turf use in the central and southern coastal area of Italy.

Leaf width (LW) influences canopy architecture of population-cultured maize and can thus contribute to density breeding. In previous studies, almost all maize LW-related mutants have extreme effect on leaf development or accompanied unfavorable phenotypes. In addition, the identification of quantitative trait loci (QTLs) has been resolution-limited, with cloning and fine-mapping rarely performed. Here, we constructed a bin map for 670 recombinant inbred lines (RILs) using ∼1.2 billion 100-bp re-sequencing reads. QTL analysis of the LW trait directly narrowed the major effect QTL, qLW4, to a ∼270-kb interval. A fine-mapping population and near-isogenic lines (NILs) were quickly constructed using a key RIL harboring heterozygous genotypes across the qLW4 region. A recombinant-derived progeny testing strategy was subsequently used to further fine-map qLW4 to a 55-kb interval. Examination of NILs revealed that qLW4 has a completely dominant effect on LW, with no additional effect on leaf length. Candidate gene analysis suggested that this locus may be a novel LW controlling allele in maize. Our findings demonstrate the advantage of large-population high-density bin mapping, and suggest a strategy for efficiently fine-mapping or even cloning of QTLs. These results should also be helpful for further dissection of the genetic mechanism of LW variation, and benefit maize density breeding.

The use of warm season turfgrasses is a consolidated trend in the climatic transition zone of Mediterranean countries, in particular St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) begins to be widespread in warm coastal areas. However, little is known about the performance of the different cultivars of this species in southern Europe. In 2016-2017 a trial was carried out in three locations in Italy, Padova, Pisa, and Palermo, located in the north, center and south of the country respectively. Four cultivars (Floratine, Captiva, Sapphire, Palmetto) and five ecotypes (CeRTES 201, CeRTES 202, CeRTES 203, CeRTES 204, CeRTES 205) were compared in terms of their growth character-istics and morphological traits during establishment. The results highlighted that stolon growth was significantly affected by the location, as well as green colour retention. Stolon growth rate, internode length and internode volume and turf quality were, how-ever, significantly determined by the accession effect. The quality of the ecotypes was also in some cases comparable to that of the cultivars. In Padova, winterkill occurred in most of the accessions, while in Pisa and Palermo, all the entries survived. In conclusion, St. Augustinegrass is suitable for turf use in the central and south-ern coastal area of Italy. [ABSTRACT FROM AUTHOR]

• Explanations of leaf size variation commonly focus on water availability, yet leaf size also varies with latitude and elevation in environments where water is not strongly limiting. We provide the first conclusive test of a prediction of leaf energy balance theory that may explain this pattern: large leaves are more vulnerable to night-time chilling, because their thick boundary layers impede convective exchange with the surrounding air. • Seedlings of 15 New Zealand evergreens spanning 12-fold variation in leaf width were exposed to clear night skies, and leaf temperatures were measured with thermocouples. We then used a global dataset to assess several climate variables as predictors of leaf size in forest assemblages. • Leaf minus air temperature was strongly correlated with leaf width, ranging from -0.9 to -3.2°C in the smallest- and largest-leaved species, respectively. Mean annual temperature and frost-free period were good predictors of evergreen angiosperm leaf size in forest assemblages, but no climate variable predicted deciduous leaf size. • Although winter deciduousness makes large leaves possible in strongly seasonal climates, large-leaved evergreens are largely confined to frost-free climates because of their susceptibility to radiative cooling. Evergreen leaf size data can therefore be used to enhance vegetation models, and to infer palaeotemperatures from fossil leaf assemblages. [ABSTRACT FROM AUTHOR]

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Leaf width (LW) influences canopy architecture of population-cultured maize and can thus contribute to density breeding. In previous studies, almost all maize LW-related mutants have extreme effect on leaf development or accompanied unfavorable phenotypes. In addition, the identification of quantitative trait loci (QTLs) has been resolution-limited, with cloning and fine-mapping rarely performed. Here, we constructed a bin map for 670 recombinant inbred lines (RILs) using 1.2 billion 100-bp re-sequencing reads. QTL analysis of the LWtrait directly narrowed the major effect QTL, qLW4, to a 270-kb interval. A fine-mapping population and near-isogenic lines (NILs) were quickly constructed using a key RIL harboring heterozygous genotypes across the qLW4 region. A recombinant-derived progeny testing strategy was subsequently used to further fine-map qLW4 to a 55-kb interval. Examination of NILs revealed that qLW4 has a completely dominant effect on LW, with no additional effect on leaf length. Candidate gene analysis suggested that this locus may be a novel LW controlling allele in maize. Our findings demonstrate the advantage of large-population high-density bin mapping, and suggest a strategy for efficiently fine-mapping or even cloning of QTLs. These results should also be helpful for further dissection of the genetic mechanism of LW variation, and benefit maize density breeding. [ABSTRACT FROM AUTHOR]

Summary: Molecular genetic analyses revealed that the WUSCHEL‐related homeobox (WOX) gene superfamily regulates several programs in plant development. Many different mechanisms are reported to underlie these alterations. The WOX family member STENOFOLIA (STF) is involved in leaf expansion in the eudicot Medicago truncutula. Here, we report that when this gene was ectopically expressed in a locally adapted hard red winter wheat cultivar (Triticum aestivum), the transgenic plants showed not only widened leaves but also accelerated flowering and increased chlorophyll content. These desirable traits were stably inherited in the progeny plants. STF binds to wheat genes that have the (GA)n/(CT)n DNA cis element, regardless of sequences flanking the DNA repeats, suggesting a mechanism for its pleiotropic effects. However, the amino acids between position 91 and 262 in the STF protein that were found to bind with the (GA)n motif have no conserved domain with any other GAGA‐binding proteins in animals or plants. We also found that STF interacted with a variety of proteins in wheat in yeast 2 hybrid assays. We conclude that the eudicot STF gene binds to (GA)n/(CT)n DNA elements and can be used to regulate leaf width, flowering time and chlorophyll content in monocot wheat. [ABSTRACT FROM AUTHOR]