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Background: Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial leguminous forages globally, known for its high yield and quality. Leaf size plays a crucial role in influencing its photosynthetic capacity, forage yield, and quality. Therefore, understanding the genetic factors regulating leaf size is of great importance for breeding new alfalfa varieties with improved yield and quality. In this study, we performed a genome-wide association study on four leaf size-related traits in 176 alfalfa germplasm resources to identify candidate genes associated with leaf size. Results: Phenotypic analysis revealed varying degrees of variation among the four traits, with coefficients of variation ranging from 3.43 to 36.84%. The broad sense heritability of these traits was found to be between 38.30% and 53.23%. Correlation analysis showed a significant positive correlation among the four traits (P < 0.01). The GWAS identified 39 SNPs associated with leaf size, distributed across eight chromosomes, of which 9 SNPs were linked to multiple traits. Haplotype analysis further confirmed that the number of superior alleles in each material was positively correlated with leaf area. Finally, we identified five genes near these 39 significant SNPs that are associated with leaf size or development. Conclusion: Our findings provide new molecular markers for marker-assisted selection in alfalfa breeding programs. Moreover, this study provides a solid foundation for subsequent functional verification and genetic improvement in alfalfa. [ABSTRACT FROM AUTHOR]

The size of leaves and fruits is a crucial agronomic and economic trait for fruit trees. The 'Bartlett' pear is a famous cultivar with succulent and delicious fruit and is cultivated globally. 'Xiang shuomi' is a bud sport of the 'Bartlett' pear, discovered in our breeding work, and exhibits enlarged leaves and fruits. However, the specific regulatory mechanism of this superior agronomic trait is still elusive. In this study, comprehensive transcriptome and metabolome analyses were performed to explore the differences in gene expression and metabolite accumulation between these two pear cultivars. The transcriptome analysis showed a total of 1279 differentially expressed genes (DEGs), with the flavonoid biosynthetic process being the most significant enriched biological process. Metabolome data indicated the detection of 412 differentially abundant metabolites (DAMs), with the metabolites of flavonoid biosynthesis being enriched significantly. The integrative transcriptomic and metabolomics analysis further confirmed the pivotal role of the flavonoid biosynthetic process in distinguishing the two cultivars. Importantly, the genes that encoded enzymes related to flavonoid biosynthesis, including CHS, CHI, HCT, LAR and CYP75B1, increased their expressions in the 'Xiang shuomi' pear. Correspondingly, the metabolites galangin, chlorogenic acid, luteolin and catechin were found to accumulate in the 'Xiang shuomi' pear. Overall, this research identified key pathways and genes influencing the fruit and leaf size of pears, providing fundamental information for the high-yield breeding of fruit trees. [ABSTRACT FROM AUTHOR]

In lunar and deep-space farming, saline stress (SS) induced by human urine in hydroponically grown vegetables constitutes one of the prime concerns in its utilization for plant nutrition. Therefore, an indoor hydroponic trial was performed to assess the effectiveness of foliar feeding of citric acid (CA, 50 µM as two sprays at 26 days and 38 days after germination using a common hand-held sprayer) and the control treatment (a standardized plant nutrient with 10% synthetic urine replacement and 50 mM NaCl-induced SS) for sugar beets. The response variables included vegetative growth traits of sugar beets, such as the height of plants and stem girth along with lengths and fresh weights of leaves, roots, and whole plants. The recorded findings demonstrated that at the fourth week of germination, CA foliar feeding did not produce a statistically significant impact on the leaf width and plant height of sugar beets. However, CA produced 17%, 14%, and 35% taller plants at the six, eight, and ten weeks of germination, respectively. Likewise, the control treatment recorded 32% and 30% smaller leaf widths of sugar beets compared to the CA foliar feeding treatment at the 8th and 10th weeks of germination, respectively. In addition, it was found that CA foliar feeding was effective in enhancing the stem length and root length by 16% and 38%, respectively compared to the control under SS. Moreover, CA foliar feeding enhanced stem diameter (26%) and root fresh weight (29%) compared to the control treatment. As far as leaf length and fresh weight along with whole plant fresh weight were concerned, foliar feeding of CA demonstrated its effectiveness by producing 32%, 21%, and 42% greater values, respectively compared to the control treatment. Therefore, CA foliar feeding could serve as a potent strategy to mitigate the deleterious effects of saline stress and boost the vegetative growth of hydroponically grown sugar beets. [ABSTRACT FROM AUTHOR]

Leaf vein, an essential part of leaf architecture, plays significant roles in shaping the proper leaf size. To date, the molecular mechanisms governing leaf development including leaf venation patterning remains poorly understood in birch. Here, we performed the genome-wide identification of homeodomain-like (HD-like) superfamily genes using phylogenetic analysis and revealed the functional role of a potential HD-like gene in leaf growth and development using transgenic technology and transcriptomic sequencing. A total of 267 HD-like genes were identified based on Arabidopsis HD-containing transcription factors, which were members of KNOTTED1-like homeobox (KNOX) family, BELL1-like homeobox (BLH) family, Zinc finger-HD (ZHD) family, HD-leucine zipper (HD-Zip) family, Golden2, ARR-B, Psr1 (GARP) family, WUSCHEL-related homeobox (WOX) family, and Myeloblastosis (MYB) and MYB-like family. Further, 41 HD-like genes showing co-expression with marker genes related to leaf vascular tissues exhibited differential expression during primary vein development. Among them, a potential HD-like gene (BpPHD4) of GARP family served as a negative factor in governing leaf size and venation patterning. Compared to non-transgenic plants, BpPHD4 repression transgenic plants showed increased leaf length, leaf width, leaf area, leaf thickness, spongy tissue thickness, stomata number, epidermal cell size, primary vein length, the distance between the secondary veins, and primary vein diameter, which was opposite to those of BpPHD4 overexpression transgenic plants. Meanwhile, reduced expression levels of BpPHD4 could remarkably promote phloem tissue development. Transcriptome analysis of BpPHD4 overexpression transgenic plants showed two candidate genes (Bpev01.c0518.g0018 and Bpev01.c2797.g0002) probably regulated by BpPHD4. To conclude, our findings contribute to a better understanding of HD-like superfamily genes and unravel the role of a potential HD-like gene in genetically controlling leaf size and venation patterning in birch, which provides clues to genetic improvement of woody plants with diverse geometric and topological properties of leaf vascular network. [ABSTRACT FROM AUTHOR]

Background: Leaves are the main organs involved in photosynthesis. They capture light energy and promote gas exchange, and their size and shape affect yield. Identifying the regulatory networks and key genes that control citrus leaf size is essential for increasing citrus crop yield. Methods: In this study, transcriptome sequencing was performed on three leaf materials: the 'Cuimi' kumquat (Nor) variety and its leaf variants, larger-leaf (VarB) and smaller-leaf (VarS) varieties. Results: Correlation and principal component analyses revealed a relatively close correlation between Nor and VarS. A total of 7264 differentially expressed genes (DEGs), including 2374 transcription factors (TFs), were identified, and 254 DEGs were common among the three materials. GO and KEGG enrichment analyses revealed significant enrichment in glucose metabolism, cell wall composition, starch biosynthesis, and photosynthesis pathways. WGCNA identified three specific modules related to the different leaf sizes of these three citrus materials. Fifteen candidate genes related to leaf size, including three transcription factors, Fh5g30470 (MYB), Fh7g07360 (AP2/ERF), and Fh5g02470 (SAP), were identified on the basis of connectivity and functional annotations. Conclusions: These findings provide a theoretical foundation for a deeper understanding of the molecular mechanisms underlying citrus leaf size and offer new genetic resources for the study of citrus leaf size. [ABSTRACT FROM AUTHOR]

SUMMARY: Leaves, as primary photosynthetic organs essential for high crop yield and quality, have attracted significant attention. The functions of DNA topoisomerase 1α (TOP1α) in various biological processes, including leaf development, in Brassica napus remain unknown. Here, four paralogs of BnaTOP1α, namely BnaA01.TOP1α, BnaA02.TOP1α, BnaC01.TOP1α and BnaC02.TOP1α, were identified and cloned in the B. napus inbred line 'K407'. Expression pattern analysis revealed that BnaA02.TOP1α and BnaC02.TOP1α, but not BnaA01.TOP1α and BnaC01.TOP1α, were persistently and highly expressed in B. napus true leaves. Preliminary analysis in Arabidopsis thaliana revealed that BnaA02.TOP1α and BnaC02.TOP1α paralogs, but not BnaA01.TOP1α and BnaC01.TOP1α, performed biological functions. Targeted mutations of four BnaTOP1α paralogs in B. napus using the CRISPR‐Cas9 system revealed that BnaA02.TOP1α and BnaC02.TOP1α served as functional paralogs and redundantly promoted true leaf number and size, thereby promoting true leaf biomass accumulation. Moreover, BnaA02.TOP1α modulated the levels of endogenous gibberellins, cytokinins and auxins by indirectly regulating several genes related to their metabolism processes. BnaA02.TOP1α directly activated BnaA03.CCS52A2 and BnaC09.AN3 by facilitating the recruitment of RNA polymerase II and modulating H3K27me3, H3K36me2 and H3K36me3 levels at these loci and indirectly activated the BnaA08.PARL1 expression, thereby positively controlling the true leaf size in B. napus. Additionally, BnaA02.TOP1α indirectly activated the BnaA07.PIN1 expression to positively regulate the true leaf number. These results reveal the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus. Significance Statement: This study helps us understand the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus. [ABSTRACT FROM AUTHOR]

SUMMARY: Leaf size is a crucial agronomic trait directly affecting crop yield, which is mainly determined by coordinated cell proliferation, growth, and differentiation. Although endoreduplication is known to be correlated with the onset of cell differentiation and leaf size, the underlying molecular mechanisms are largely unclear. The DnaJ‐like zinc finger domain‐containing protein ORANGE (OR) was initially demonstrated to confer the massive accumulation of carotenoids in cauliflower curds. However, the cauliflower or mutant also possesses other phenotypes such as smaller curds, smaller leaves with elongated petioles, and delayed flowering. Here, we demonstrated that OR physically interacts with the transcription factor TCP7, which promotes endoreduplication by inducing the expression of the cell cycle gene CYCLIN D 1;1 (CYCD1;1). Overexpression of OR resulted in smaller rosette leaves, whereas the OR‐silencing plants had larger rosette leaves than wild‐type plants. Our microscopic observations and flow cytometry analysis revealed that the variation in leaf size was a result of different endoreduplication levels. Genetic analyses showed that OR functions antagonistically with TCP7 in regulating the endoreduplication levels in leaf cells. While the expression of OR is induced by TCP7, OR represses the transactivation activity of TCP7 by affecting its binding capability to the TCP‐binding motif in the promoter region of CYCD1;1. Through this interaction, OR negatively regulates the expression of CYCD1;1 and reduces the nuclear ploidy level in rosette leaf cells. Our findings provide new insights into the regulatory network of leaf size and also reveal a regulatory circuit controlling endoreduplication in leaf cells. Significance Statement: The zinc finger domain‐containing protein ORANGE (OR) has been reported to possess multiple functions in regulating carotenoid biosynthesis, petiole elongation, flowering, and de‐etiolation. Here, we demonstrated that, by repressing the transactivation activity of TCP7 through protein–protein interaction, OR negatively regulates the expression of the cell cycle gene CYCD1;1 and reduces the nuclear ploidy level in rosette leaf cells. [ABSTRACT FROM AUTHOR]

The processes of developmental stability, canalization, and phenotypic plasticity have ecological and evolutionary significance, and been studied extensively, but mostly separately and thus the relationships between them are not straightforward. Our objective was to better integrate these processes in the context of temporally heterogeneous environments. We did this by investigating the effects of early experience with temporal heterogeneity in water availability on associations between developmental stability, canalization, and phenotypic plasticity. We subjected eight plant species to a first round of alternating inundation and drought vs. constantly moderate water treatments (heterogeneous experience) and a second round of water conditions (to test plasticity). We measured fluctuating asymmetry (FA) in leaf size, intra‐ and inter‐individual variation (CVintra and CVinter), and plasticity (PI) in traits and analyzed correlations between these variables across all species. Results showed little correlations between FA, CVintra and PI, several positive correlations between FA and CVinter in more stressful conditions, especially in as well as positive correlations between CVinter and PI initially and negative correlations between them later. These suggested the complexity of these relationships, which can depend on whether plasticity occurs. Greater inter‐individual variation will more likely cooperate with plasticity before or during plastic response, whereas higher canalization may reflect phenotypic convergence. Both higher FA and CVintra can reflect faster growth, while CVintra may also reflect plant growth stage, and the two mechanisms should cooperate in response to environmental challenges. The complexity of these relationships suggests plants deal with environmental variation in elaborate and integrative ways which can be affected by many factors. [ABSTRACT FROM AUTHOR]

Aspen (Populus tremula L.) is a keystone species and a model system for forest tree genomics. We present an updated resource comprising a chromosome‐scale assembly, population genetics and genomics data. Using the resource, we explore the genetic basis of natural variation in leaf size and shape, traits with complex genetic architecture. We generated the genome assembly using long‐read sequencing, optical and high‐density genetic maps. We conducted whole‐genome resequencing of the Umeå Aspen (UmAsp) collection. Using the assembly and re‐sequencing data from the UmAsp, Swedish Aspen (SwAsp) and Scottish Aspen (ScotAsp) collections we performed genome‐wide association analyses (GWAS) using Single Nucleotide Polymorphisms (SNPs) for 26 leaf physiognomy phenotypes. We conducted Assay of Transposase Accessible Chromatin sequencing (ATAC‐Seq), identified genomic regions of accessible chromatin, and subset SNPs to these regions, improving the GWAS detection rate. We identified candidate long non‐coding RNAs in leaf samples, quantified their expression in an updated co‐expression network, and used this to explore the functions of candidate genes identified from the GWAS. A GWAS found SNP associations for seven traits. The associated SNPs were in or near genes annotated with developmental functions, which represent candidates for further study. Of particular interest was a ~177‐kbp region harbouring associations with several leaf phenotypes in ScotAsp. We have incorporated the assembly, population genetics, genomics, and GWAS data into the PlantGenIE.org web resource, including updating existing genomics data to the new genome version, to enable easy exploration and visualisation. We provide all raw and processed data to facilitate reuse in future studies. [ABSTRACT FROM AUTHOR]

The "leafing intensity premium" hypothesis proposes that leaf size results from natural selection acting on different leafing intensities, i.e., the number of leaves per unit shoot volume or mass. The scaling relationships among various above-ground functional traits in the context of this hypothesis are important for understanding plant growth and ecology. Yet, they have not been sufficiently studied. In this study, we selected four bamboo species of the genus Indocalamus Nakai and measured the total leaf fresh mass per culm, total non-leaf above-ground fresh mass, total number of leaves per culm, and above-ground culm height of 90 culms from each species. These data were used to calculate leafing intensity (i.e., the total number of leaves per culm divided by the total non-leaf above-ground fresh mass) and mean leaf fresh mass per culm (i.e., the total leaf fresh mass per culm divided by the total number of leaves per culm). Reduced major axis regression protocols were then used to determine the scaling relationships among the various above-ground functional traits and leafing intensity. Among the four species, three exhibited an isometric (one-to-one) relationship between the total leaf fresh mass per culm and the total non-leaf above-ground fresh mass, whereas one species (Indocalamus pumilus) exhibited an allometric (not one-to-one) relationship. A negative isometric relationship was found between the mean leaf fresh mass per culm and the leafing intensity for one species (Indocalamus pedalis), whereas three negative allometric relationships between mean leaf fresh mass per culm and leafing intensity were observed for the other three species and the pooled data. An exploration of the alternative definitions of "leafing intensity" showed that the total number of leaves per culm divided by the above-ground culm height is superior because it facilitates the non-destructive calculation of leafing intensity for Indocalamus species. These results not only confirm the leafing intensity premium hypothesis for bamboo species but also highlight the interconnected scaling relationships among different functional traits, thereby contributing to our understanding of the ecological and evolutionary significance of leaf size variation and biomass investment strategies. [ABSTRACT FROM AUTHOR]

Foliar development involves successive phases of cell proliferation and expansion that determine the final leaf size, and is characterized by an early burst of reactive oxygen species generated in the photosynthetic electron transport chain (PETC). Introduction of the alternative PETC acceptor flavodoxin in tobacco chloroplasts led to a reduction in leaf size associated to lower cell expansion, without affecting cell number per leaf. Proteomic analysis showed that the biogenesis of the PETC proceeded stepwise in wild-type leaves, with accumulation of light-harvesting proteins preceding that of electron transport components, which might explain the increased energy and electron transfer to oxygen and reactive oxygen species build-up at this stage. Flavodoxin expression did not affect biogenesis of the PETC but prevented hydroperoxide formation through its function as electron sink. Mature leaves from flavodoxin-expressing plants were shown to contain higher levels of transcripts encoding components of the proteasome, a key negative modulator of organ size. Proteome profiling revealed that this differential accumulation was initiated during expansion and led to increased proteasomal activity, whereas a proteasome inhibitor reverted the flavodoxin-dependent size phenotype. Cells expressing plastid-targeted flavodoxin displayed lower endoreduplication, also associated to decreased organ size. These results provide novel insights into the regulation of leaf growth by chloroplast-generated redox signals, and highlight the potential of alternative electron shuttles to investigate the link(s) between photosynthesis and plant development. [ABSTRACT FROM AUTHOR]

Summary: Increased planting densities boost crop yields. A compact plant architecture facilitates dense planting. However, the mechanisms regulating compact plant architecture in cucurbits remain unclear. In this study, we identified a cucumber (Cucumis sativus) compact plant architecture (cpa1) mutant from an ethyl methane sulfonate (EMS)‐mutagenized library that exhibited distinctive phenotypic traits, including reduced leaf petiole angle and leaf size. The candidate mutation causes a premature stop codon in CsaV3_1G036420, which shares similarity to Arabidopsis HOOKLESS 1 (HLS1) encoding putative histone N‐acetyltransferase (HAT) protein and was named CsHLS1. Consistent with the mutant phenotype, CsHLS1 was predominantly expressed in leaf petiole bases and leaves. Constitutive overexpressing CsHLS1 in cpa1 restored the wild‐type plant architecture. Knockout of CsHLS1 resulted in reduces leaf petiole angle and leaf size and as well as decreased acetylation levels. Furthermore, CsHLS1 directly interacted with CsSCL28 and negatively regulated compact plant architecture in cucumber. Importantly, CsHLS1 knockout increased the photosynthesis rate and leaf nitrogen in cucumbers, thereby maintaining cucumber yield at normal density. Overall, our research provides valuable genetic breeding resource and gene target for creating a compact plant architecture for dense cucumber planting. [ABSTRACT FROM AUTHOR]

Plant structure-related agronomic traits like plant height and leaf size are critical for growth, development, and crop yield. Defining the types of genes involved in regulating plant structure size is essential for the molecular-assisted breeding of peppers. This research conducted comparative transcriptome analyses using Capsicum baccatum germplasm HNUCB0112 and HNUCB0222 and their F2 generation as materials. A total of 6574 differentially expressed genes (DEGs) were detected, which contain 379 differentially expressed transcription factors, mainly including transcription factor families such as TCP, WRKY, AUX/IAA, and MYB. Seven classes of DEGs were annotated in the plant hormone signal transduction pathway, including indole acetic acid (IAA), gibberellin (GA), cytokinin (CK), abscisic acid (ABA), jasmonic acid (JA), ethylene (ET), and salicylic acid (SA). The 26 modules were obtained by WGCNA analysis, and the MEpink module was positively correlated with plant height and leaf size, and hub genes associated with plant height and leaf size were anticipated. Differential genes were verified by qRT-PCR, which was consistent with the RNA-Seq results, demonstrating the accuracy of the sequencing results. These results enhance our understanding of the developmental regulatory networks governing pepper key traits like plant height and leaf size and offer new information for future research on the pepper plant architecture system. [ABSTRACT FROM AUTHOR]

Leaves are the predominant photosynthetic and edible organs in non-heading Chinese cabbage (Brassica campestris ssp. chinensis, NHCC), contributing significantly to yield, appearance, and desirability to consumers. However, the genetic basis of leaf shape and size in non-heading Chinese cabbage remains unclear. In this study, we developed a RIL population using 'Maertou', with slender leaves and narrow petioles, and 'Suzhouqing', with oval leaves and wide petioles, to construct a genetic linkage map and detect QTLs. To obtain stable and reliable QTLs, the 11 leaf-related traits, including the leaf length, leaf width, and fresh weight of the lamina and petiole and the thickness of petiole was observed on two locations—while the leaf shape, petiole shape, index of lamina/petiole length, and index of petiole fresh weight were calculated based on 7 leaf-related traits. QTL mapping illustrated that a total of 27 QTLs for leaf-related traits were preliminarily detected. The candidate genes were annotated and several genes involved in leaf development and leaf shape appeared in the overlapping regions of multiple loci, such as KRP2, GRF4, ARGOS, and SAUR9. This study lays the foundation for further exploration of the genetic mechanisms and development of effective molecular markers for leaf shape and size in NHCC. [ABSTRACT FROM AUTHOR]

Leaves are the main photosynthesis organ that directly determines crop yield and biomass. Dissecting the regulatory mechanism of leaf development is crucial for food security and ecosystem turn‐over. Here, we identified the novel function of R2R3‐MYB transcription factors CsRAXs in regulating cucumber leaf size and fruiting ability. Csrax5 single mutant exhibited enlarged leaf size and stem diameter, and Csrax1/2/5 triple mutant displayed further enlargement phenotype. Overexpression of CsRAX1 or CsRAX5 gave rise to smaller leaf and thinner stem. The fruiting ability of Csrax1/2/5 plants was significantly enhanced, while that of CsRAX5 overexpression lines was greatly weakened. Similarly, cell number and free auxin level were elevated in mutant plants while decreased in overexpression lines. Biochemical data indicated that CsRAX1/5 directly promoted the expression of auxin glucosyltransferase gene CsUGT74E2. Therefore, our data suggested that CsRAXs function as repressors for leaf size development by promoting auxin glycosylation to decrease free auxin level and cell division in cucumber. Our findings provide new gene targets for cucumber breeding with increased leaf size and crop yield. [ABSTRACT FROM AUTHOR]

Premise: With the global atmospheric CO2 concentration on the rise, developing crops that can thrive in elevated CO2 has become paramount. We investigated the potential of hybridization as a strategy for creating crops with improved growth in predicted elevated atmospheric CO2. Methods: We grew parent accessions and their F1 hybrids of Arabidopsis thaliana in ambient and elevated atmospheric CO2 and analyzed numerous growth traits to assess their productivity and underlying mechanisms. Results: The heterotic increase in total dry mass, relative growth rate and leaf net assimilation rate was significantly greater in elevated CO2 than in ambient CO2. The CO2 response of net assimilation rate was positively correlated with the CO2 response of leaf nitrogen productivity and with that of leaf traits such as leaf size and thickness, suggesting that hybridization‐induced changes in leaf traits greatly affected the improved performance in elevated CO2. Conclusions: Vegetative growth of hybrids seems to be enhanced in elevated CO2 due to improved photosynthetic nitrogen‐use efficiency compared with parents. The results suggest that hybrid crops should be well‐suited for future conditions, but hybrid weeds may also be more competitive. [ABSTRACT FROM AUTHOR]

Functional traits have been proposed to define key dimensions of plant ecological strategies, but we lack consensus on whether traits can accurately predict plant demography. Despite theoretical expectations, it has been challenging to find consistent relationships between functional traits and growth.In this study, we quantified inter‐ and intraspecific trait variation (ITV) and individual growth rates of woody plants across a steep moisture gradient that varies 10‐fold in annual precipitation (350–3700 mm) in southern Chile and used a hierarchical Bayesian model to predict growth as a function of trait values.We show that large‐leaved species with lower stem tissue density exhibited the fastest growth rates, and these two traits exhibited the highest proportion of interspecific variation. Predictions of growth improved considerably (R2 of the best model increased from 0.28 to 0.49) when species‐level multiple traits and their interactions were considered. The inclusion of ITV, however, did not improve models of growth rate.We found that trait–growth rate relationships were not always consistent across levels of biological organization; relationships observed at the interspecific level did not necessarily hold at the intraspecific level. We found that the relationships between wood density or leaf size and growth were consistent in direction across the precipitation gradient, and the relationships between leaf economics traits and growth were weak and site‐specific.Synthesis. Although using more than one functional trait considerably improved growth predictions, wood density and leaf size successfully predicted growth rates across (not within) species, which is consistent with a whole‐plant carbon economy. We assert that these two traits are intimately linked and ultimately describe a continuum of plant architecture and carbon economy that covers multiple trait syndromes. [ABSTRACT FROM AUTHOR]

Leaf growth initiates in the peripheral region of the meristem at the apex of the stem, eventually forming flat structures. Leaves are pivotal organs in plants, serving as the primary sites for photosynthesis, respiration, and transpiration. Their development is intricately governed by complex regulatory networks. Leaf development encompasses five processes: the leaf primordium initiation, the leaf polarity establishment, leaf size expansion, shaping of leaf, and leaf senescence. The leaf primordia starts from the side of the growth cone at the apex of the stem. Under the precise regulation of a series of genes, the leaf primordia establishes adaxial-abaxial axes, proximal-distal axes and medio-lateral axes polarity, guides the primordia cells to divide and differentiate in a specific direction, and finally develops into leaves of a certain shape and size. Leaf senescence is a kind of programmed cell death that occurs in plants, and as it is the last stage of leaf development. Each of these processes is meticulously coordinated through the intricate interplay among transcriptional regulatory factors, microRNAs, and plant hormones. This review is dedicated to examining the regulatory influences of major regulatory factors and plant hormones on these five developmental aspects of leaves. [ABSTRACT FROM AUTHOR]

Leaf size significantly impacts photosynthetic capacity and forage yield in alfalfa, a major legume forage crop. Therefore, elucidating the genetic factors governing leaf development is critical for breeding improved alfalfa varieties. In this study, a genome-wide association analysis (GWAS) was performed to dissect the genetic architecture of leaf length (LL) and leaf width (LW) using 220 alfalfa accessions phenotyped over three years. Substantial variation for both traits was observed across environments, with coefficients of variation ranging from 10.09–16.53%. GWAS identified 26 significant SNPs associated with leaf morphology spread across seven chromosomes. Each SNP accounts for 9.7–15.6% of the phenotypic variance. Haplotype analyses confirmed positive correlations between the number of superior alleles and both LL and LW. BLAST searches revealed six candidate genes involved in leaf development within 20 kb flanking regions of significant SNPs. Our results provide novel marker-trait associations and candidate loci to facilitate molecular breeding efforts to optimize leaf size and improve productivity in alfalfa. This study establishes a foundation for integrating favorable alleles into future alfalfa varieties. [ABSTRACT FROM AUTHOR]

A 50-year-old solitary, sun-exposed ginkgo tree had strongly been pruned in the fall of 2021. Very few buds for the formation of new leaves, twigs, and branches were left over. In spring 2022, these few remaining buds responded with the formation of a different leaf type. These leaves were 2.7 times larger and also thicker than in the years before. In addition, the mean content of total chlorophylls [Chl (a+b)] per leaf area unit of dark-green leaves was 1.45, those of green leaves two times higher as compared to the years before pruning and the two other ginkgo trees which had been investigated in parallel. A comparable increase was also found for the level of total carotenoids (x+c). The mean content for Chl (a+b) were 1,118 mg m-2 for dark-green and 898 mg m-2 for green leaves as compared to 435 to 770 mg m-2 in leaves of other trees. The higher values for Chl (a+b) and total carotenoid content showed up also on a fresh and dry mass basis. Thus, with the formation of a new, larger leaf type by changes in morphology (leaf size and thickness) and the increase of photosynthetic pigments, the pruned ginkgo tree was able to compensate for the much lower number of leaves and photosynthetic units. [ABSTRACT FROM AUTHOR]

Image analysis is a promising method for in situ leaf area measurement. However, as leaves are three-dimensional, the use of two-dimensional images captured using a digital camera can result in underestimation. To overcome this problem, we tested a clear folder method. Before photographing leaves with a digital camera, we flattened the leaves by sandwiching them between a pair of transparent plastic clear file folder sheets, which are stationery implements for carrying documents. Although similar methods have been previously proposed, their applicability to species with different leaf shapes has never been investigated. We tested the efficacy of this method using 12 species from various taxa (monocots, magnoliids, and basal and core eudicots) and leaf morphology (entire vs. lobed, simple vs. compound leaves, small and large leaves). Individual leaf areas and the Montgomery parameters obtained using this method were then compared with those obtained using the standard method, which employs a flatbed digital scanner. We observed strong correlations (R2 > 0.98) between the camera and scanner data. The regression slopes were close to unity (0.96–1.01) and the intercepts were close to zero. These findings suggest that the clear folder method can be used as an inexpensive alternative method to estimate the area of leaves in situ with acceptable accuracy. An introductory manual for readers unfamiliar with image analysis using ImageJ is presented in the end of the paper. [ABSTRACT FROM AUTHOR]

Factors shaping the interspecific variations in herbivory have puzzled ecologists for decades and several hypotheses have been proposed to explain interspecific variation in leaf herbivory. In a tropical rainforest in Yunnan Province, China, we collected 6732 leaves from 129 species with canopy heights ranging from 1.6 to 65.0 m above the ground. We tested the role of canopy height, the diversity, composition and structural heterogeneity of neighbors and leaf traits in shaping the interspecific variations in herbivory. Results show that leaf herbivory decreased with canopy height and specific leaf area (SLA) and increased with leaf size. However, neighboring species' diversity, composition, and structural heterogeneity showed no association with herbivory. Therefore, neither the visual apparency effect nor the associational resistance effect was detected in this hyperdiverse tropical rainforest. These findings highlight the importance of vertical structure in shaping herbivory patterns in natural communities. [ABSTRACT FROM AUTHOR]

Introduction: The leaf, the main product organ, is an essential factor in determining the Chinese cabbage growth, yield and quality. Methods: To explore the regulatory mechanism of leaf size development of Chinese cabbage, we investigated the leaf size difference between two highgeneration inbred lines of Chinese cabbage, Y2 (large leaf) and Y7 (small leaf). Furtherly, the transcriptome and cis-acting elements analyses were conducted. Results and Discussion: According to our results, Y2 exhibited a higher growth rate than Y7 during the whole growth stage. In addition, the significant higher leaf number was observed in Y2 than in Y7. There was no significant difference in the number of epidermal cells and guard cells per square millimeter between Y2 and Y7 leaves. It indicated that cell numbers caused the difference in leaf size. The measurement of phytohormone content confirmed that GA1 and GA3 mainly play essential roles in the early stage of leaf growth, and IPA and ABA were in the whole leaf growth period in regulating the cell proliferation difference between Y2 and Y7. Transcriptome analysis revealed that cyclins BraA09g010980.3C (CYCB) and BraA10g027420.3C (CYCD) were mainly responsible for the leaf size difference between Y2 and Y7 Chinese cabbage. Further, we revealed that the transcription factors BraA09gMYB47 and BraA06gMYB88 played critical roles in the difference of leaf size between Y2 and Y7 through the regulation of cell proliferation. Conclusion: This observation not only offers essential insights into understanding the regulation mechanism of leaf development, also provides a promising breeding strategy to improve Chinese cabbage yield. [ABSTRACT FROM AUTHOR]

Widely accepted universal models and hypotheses such as 'high vein density-faster growth and higher productivity' hold that high leaf vein density may promote higher coupling efficiency of carbon and water, indicating that rapid individual growth and high stand productivity, have attracted huge interest. However, these models and hypotheses do not include enough gymnosperm samples, especially conifers cultivated in subtropics. We here examined the values and scaling relationships between leaf vein density and leaf functional traits sampled from center region of the distribution range of Cunninghamia lanceolate , which has been well known for rapid growth. We also retrieved an empirical dataset that included photosynthetic, biochemical, anatomical and hydraulic traits of Cunninghamia lanceolata. The leaf vein density (ranging from 0.34 to 1.09 mm mm−2) is extremely low compared to the reported global range (1 to 25 mm mm−2), whereas C. lanceolata is famous for both fast-growing and high-yielding in China for a long time. We further verified that higher vein densities were associated with smaller leaves (r = −0.71, P < 0.001), which is consistent with that found in angiosperms. However, we found that vein density–thickness correlations and leaf lifespan plasticity showed opposite trends for C. lanceolate (negative) when compared with global species (positive), and such relationships may indicate the tradeoffs between functional efficiency and productivities. Our results provide an effective complementary assessment of general growth rules, including evaluation of the influence of regional plant trait characterization, configuration of plant species, and traits efficiency for hydraulic potential. [ABSTRACT FROM AUTHOR]

A more efficient attention recovery of workers during their break time is essential for achieving higher productivity and wellness. In recent years, the biophilic design that introduces indoor plants has become one of the solutions to these problems. This study aims to determine the impact factors and corresponding levels related to indoor planting design concerning workers' attention recovery. Firstly, the volume ratio, layout, and leaf size of indoor plants and the corresponding levels were put forward by a focus group study with ten participants. Secondly, the orthogonal experiment method established nine virtual recovery scenarios based on characteristics extraction of staff break areas in the factory. Thirdly, eighteen participants were guided to feel fatigued by experiencing the sustained attention to response test to measure the baseline attention level of participants. Then, participants rested in the virtual scenarios. Lastly, the attention test was conducted again to observe participants' attention recovery degree. The difference values of participants' sensitivity, reaction times, and the number of correct responses between the two detection targets were applied to evaluate the attention recovery. Results showed that the volume ratio of indoor plants had the most significant effect on workers' attention recovery; 3% by volume ratio, mixed floor and wall plants and floor planting with large leaves were demonstrated as the optimal indoor planting design for attention recovery. [ABSTRACT FROM AUTHOR]

Key message: We proposed a working model of BR to promote leaf size through cell expansion. In the BR signaling pathway, GhBES1 affects cotton leaf size by binding to and activating the expression of the E-box element in the GhEXO2 promoter region. Brassinosteroid (BR) is an essential phytohormone that controls plant growth. However, the mechanisms of BR regulation of leaf size remain to be determined. Here, we found that the BR deficient cotton mutant pagoda1 (pag1) had a smaller leaf size than wild-type CRI24. The expression of EXORDIUM (GhEXO2) gene, was significantly downregulated in pag1. Silencing of BRI1-EMS-SUPPRESSOR 1 (GhBES1), inhibited leaf cell expansion and reduced leaf size. Overexpression of GhBES1.4 promoted leaf cell expansion and enlarged leaf size. Expression analysis showed GhEXO2 expression positively correlated with GhBES1 expression. In plants, altered expression of GhEXO2 promoted leaf cell expansion affecting leaf size. Furthermore, GhBES1.4 specifically binds to the E-box elements in the GhEXO2 promoter, inducing its expression. RNA-seq data revealed many down-regulated genes related to cell expansion in GhEXO2 silenced plants. In summary, we discovered a novel mechanism of BR regulation of leaf size through GhBES1 directly activating the expression of GhEXO2. [ABSTRACT FROM AUTHOR]

Larvae of the Indian red admiral butterfly, Vanessa indica (Herbst, 1794), fold the leaves of the host plants along the midvein to construct shelters. Usually, one leaf is used for every shelter, although more than one leaf are sometimes used. To determine the conditions under which larvae use more than one leaf to construct a shelter, a field investigation of the larval shelters was conducted. Early instar larvae used multiple leaves in a shelter when a larger leaf served as the main leaf. In comparison, in later instars used multiple leaves when a smaller leaf served as the main leaf. When an early instar larva uses a large, tough leaf, it may not be able to fold it sufficiently and there may be gaps in the surface of the shelter. In such a case, a larva in the early instar may add nearby leaves to cover the gaps, so that the shelter has more than one leaf. Because later instar larvae can fold a leaf tightly, their shelters have no gaps. When later instar larvae use a small leaf, multiple leaves will be needed to expand the shelters within which they hide and feed. [ABSTRACT FROM AUTHOR]

When the shoot apical meristem of plants is damaged or removed, fecundity and/or plant growth may suffer (under-compensation), remain unaffected (compensation) or increase (overcompensation). The latter signifies a potential 'cost' of apical dominance. Using natural populations of 19 herbaceous angiosperm species with a conspicuously vertical, apically dominant growth form, we removed (clipped) the shoot apical meristem for replicate plants early in the growing season to test for a potential cost of apical dominance. Clipped and unclipped (control) plants had their near neighbours removed, and were harvested after flowering production had finished but before seed dispersal. Dry mass was measured separately for aboveground body size (shoots), leaves, seeds and fruits; and number of leaves, fruits and seeds per plant were counted. We predicted that: (i) our study species (because of their strong apically dominant growth form) would respond to shoot apical meristem removal with greater branching intensity, and thus overcompensation in terms of fecundity and/or biomass; and (ii) overcompensation is particularly enabled for species that produce smaller but more leaves, and hence with a larger bud bank of axillary meristems available for deployment in branching and/or fruit production. Widely variable compensatory capacities were recorded, and with no significant between-species relationship with leaf size or leafing intensity—thus indicating no generalized potential cost of apical dominance. Overall, the results point to species-specific treatment effects on meristem allocation patterns, and suggest importance for effects involving local variation in resource availability, and between-species variation in phenology, life history traits and susceptibility to herbivory. [ABSTRACT FROM AUTHOR]

Leaf morphological and physiological traits control the carbon and water relations of mature trees and are determinants of drought tolerance, but it is not well understood how they are modified in response to water deficits.We analysed five sun‐canopy leaf traits (mean leaf size (LS), specific leaf area (SLA), Huber value (HV), water potential at turgor loss point (Ψtlp) and foliar carbon isotope signature (δ13C)) in European beech (Fagus sylvatica L.) across three precipitation gradients sampled in moist (2010), dry (2019) and very dry (2018) summers, and tested their response to short‐term water deficits (climatic water balance (CWB) preceding sample collection) and long‐term water availability (mean annual precipitation (MAP), plant‐available soil water capacity (AWC) and neighbourhood competition).Across the 34 sites, LS varied seven‐fold (3.9−27.0 cm2), SLA four‐fold (77.1−306.9 cm²·g−1) and HV six‐fold (1.0−6.65 cm2·m−2). In the 2018 dataset, LS showed a negative and HV a positive relationship to MAP, which contradicts relations found in multi‐species samples. Average Ψtlp ranged from −1.90 to −2.62 MPa and decreased across the sites with decreasing CWB in the month prior to measurement, as well as with decreasing MAP and AWC in 2019. Studied leaf traits varied considerably between years, suggesting that mast fruiting and the severe 2018 drought caused the formation of smaller leaves.We conclude that sun‐canopy leaf traits of European beech exhibit considerable plasticity in response to climatic and edaphic aridity, and that osmotic adjustment may be an important element in the drought response strategy of this anisohydric tree species. [ABSTRACT FROM AUTHOR]

Cyclins are involved in cell division and proliferation by activating enzymes required for the cell cycle progression. Our genome-wide analysis identified 76 cyclin genes in Brassica rapa, which were divided into nine different types (A-, B-, C-, D-, H-, L-, P-, T-, and SDS-type). Cyclin genes were unevenly scattered on all chromosomes, with a maximum of 10 on A08 and a minimum of 2 on A04. The gene structure and conserved motif analysis showed that the cyclins which belonged to the same type or subgroup have a comparable intron/exon pattern or motif. A total of 14 collinear gene pairs suggested that the B. rapa cyclin genes experienced a mass of segmental duplication. The Ka/Ks analysis revealed that the Brcyclin gene family has undergone an extensive purifying pressure. By analyzing the cis-elements in the promoters, we identified 11 cis-elements and five of them are related to the hormone response. We observed 48 potential miRNAs targeting 44 Brcyclin genes, which highlighted the involvement of miRNAs in the regulation of cyclin genes. An association analysis between the leaf size and SNPs in mutants and a transcriptome analysis of two Chinese cabbage-cabbage translocation lines also showed that the Brcyclin gene family was involved in the development of the leaves. The functional characterization of the B. rapa cyclin gene family will provide the foundation for future physiological and genetic studies in the regulation of leaf growth. [ABSTRACT FROM AUTHOR]

AINTEGUMENTA-LIKE (AIL) transcription factors are widely studied and play crucial roles in plant growth and development. However, the functions of the AIL family in legume species are largely unknown. In this study, 11 MtAIL genes were identified in the model legume Medicago truncatula, of which four of them are MtANTs. In situ analysis showed that MtANT1 was highly expressed in the shoot apical meristem (SAM) and leaf primordium. Characterization of mtant1 mtant2 mtant3 mtant4 quadruple mutants and MtANT1-overexpressing plants revealed that MtANTs were not only necessary but also sufficient for the regulation of leaf size, and indicated that they mainly function in the regulation of cell proliferation during secondary morphogenesis of leaves in M. truncatula. This study systematically analyzed the MtAIL family at the genome-wide level and revealed the functions of MtANTs in leaf growth. Thus, these genes may provide a potential application for promoting the biomass of legume forages. [ABSTRACT FROM AUTHOR]

Plant polyploidization changes its leaf morphology and leaf development patterns. Understanding changes in leaf morphology and development patterns is a prerequisite and key to studying leaf development in polyploid plants. In this study, we quantified and analyzed the differences in leaf morphology, leaf growth polarity, and leaf size between diploid and tetraploid birches (Betula pendula subsp. pendula), and preliminarily investigated genes involved in leaf growth and development in birch. The results showed significant changes in leaf morphology in tetraploid birches, especially the basal part of the leaf. In addition, the proximal growth rate of tetraploid leaves was altered. The changed proximal growth rate did not affect the growth polarity pattern of tetraploid leaves. The leaf area of tetraploid was significantly larger than that of diploid birch. The difference in leaf size was mainly due to differences in their growth rates in the middle and late stages of leaf development. Increased cell expansion capacity was the major reason for the enormous leaves of tetraploid birch; however, cell proliferation did not contribute to the larger tetraploid leaf. The gene expression of ATHB12 was associated with cell size and leaf area, and may be a critical gene affecting the leaf size in diploid and tetraploid birches. The results will provide valuable insights into plant polyploid leaf development and a theoretical basis for later investigations into the molecular mechanisms underlying the gigantism of tetraploid birch leaves. [ABSTRACT FROM AUTHOR]

Leaf size is a crucial trait in eggplant breeding, as it influences photosynthesis, plant biomass and management. However, little is known about the molecular mechanism regulating leaf size in eggplant. This study reports a small leaf mutant (slf) generated with the mutagen ethyl methane sulfonate (EMS). The slf mutant showed restricted cell proliferation and an increased content of auxin. Transcriptome analysis revealed that several genes involved in auxin signaling are upregulated in slf. Exogenous application of auxinole, an auxin antagonist of TIR1/AFB receptors, repressed the expression of these genes and restored leaf growth of slf, suggesting that the small leaf size of slf is likely associated with auxin signaling. This study provides essential clues to unveil the molecular mechanism of leaf size regulation in eggplant. [ABSTRACT FROM AUTHOR]

Seidlitzia rosmarinus Boiss. has been identified as one of the potential species that could be used for rehabilitating degraded desert rangelands and salt‐affected soils due to its high salinity resistance and soil‐stabilizing ability. Morphological variation of 144 accessions of this species from 14 regions of the Isfahan province, Iran was investigated. The accessions studied were significantly different in terms of the traits recorded. Three forms of plant growth habit were observed, including spreading bush, erect bush, and shrub. The range of leaf dimensions was as follows: terminal leaf length: 1.57–7.22 mm, terminal leaf width: 0.91–3.34 mm, basal leaf length: 11.84–45.27 mm, and basal leaf width: 1.32–4.18 mm. Fruit diameter (with wings) ranged from 0.19 to 12.91 mm, and 100‐fruits dry weight varied between 0.11 and 0.76 g. A dendrogram created using Euclidean distances and the Ward's method revealed two main clusters. The obtained data revealed the morphological diversity within the studied populations. The reason for such a high diversity can be explained by a low probability of gene flow among the studied accessions. This is the first report on the application of morphological characteristics in the evaluation of the phenotypic variation of S. rosmarinus. This study presented a high phenotypic diversity of S. rosmarinus germplasm that could provide useful information for conservation and selection of cross‐parents in breeding. [ABSTRACT FROM AUTHOR]

The flora of Tehsil Utman Khel, District Bajaur comprised of total 238 plant species belonging to 208 genera and 89 families. Among them, 59 species were identified as Non-native. The dominant family was Poaceae (17 species) which was followed by Asteraceae (15 species), Papilionaceae Rosaceae (13 species each), and Solanaceae (10 species). The habit of flora was led by herbs (149 species, 62.6%) followed by shrubs (46 species, 20%) and trees (43 species, 18%). There were 177 wild species and 61 cultivated species. The leading life forms were therophytes having 83 species and nanophanerophytes 49 species. Microphylls with 89 species, Mesophylls with 75 species and nanophylls with 43 species were the leading leaf size classes. Simple leaves (156 species, 65.55%) followed by compound leaves (18.91%), dissected leaves (10.51%) and needle leaves (3.78 %) were the documented leaf types. [ABSTRACT FROM AUTHOR]

Growth-regulating factors (GRFs) play crucial roles in plant growth and stress response. To date, there have been no reports of the analysis and identification of the GRF transcription factor family in alfalfa. In this study, we identified 27 GRF family members from alfalfa (Medicago sativa L.) "Xinjiang Daye", and analyzed their physicochemical properties. Based on phylogenetic analysis, these MsGRFs were divided into five subgroups, each with a similar gene structure and conserved motifs. MsGRFs genes are distributed on 23 chromosomes, and all contain QLQ and WRC conserved domains. The results of the collinearity analysis showed that all MsGRFs are involved in gene duplication, including multiple whole-genome duplication or segmental duplication and a set of tandem duplication, indicating that large-scale duplication is important for the expansion of the GRF family in alfalfa. Several hormone-related and stress-related cis-acting elements have been found in the promoter regions of MsGRFs. Some MsGRFs were highly expressed in young leaves and stems, and their expression decreased during development. In addition, the leaf size of different varieties was found to vary, and MsGRF1 to 4, MsGRF18 to 20, and MsGRF22 to 23 were differentially expressed in large and small leaf alfalfa varieties, suggesting that they are critical in the regulation of leaf size. The results of this study can benefit further exploration of the regulatory functions of MsGRFs in growth and development, and can identify candidate genes that control leaf size development. [ABSTRACT FROM AUTHOR]

Background and Aims An individual plant consists of different-sized shoots, each of which consists of different-sized leaves. To predict plant-level physiological responses from the responses of individual leaves, modelling this within-shoot leaf size variation is necessary. Within-plant leaf trait variation has been well investigated in canopy photosynthesis models but less so in plant allometry. Therefore, integration of these two different approaches is needed. Methods We focused on an established leaf-level relationship that the area of an individual leaf lamina is proportional to the product of its length and width. The geometric interpretation of this equation is that different-sized leaf laminas from a single species share the same basic form. Based on this shared basic form, we synthesized a new length-times-width equation predicting total shoot leaf area from the collective dimensions of leaves that comprise a shoot. Furthermore, we showed that several previously established empirical relationships, including the allometric relationships between total shoot leaf area, maximum individual leaf length within the shoot and total leaf number of the shoot, can be unified under the same geometric argument. We tested the model predictions using five species, all of which have simple leaves, selected from diverse taxa (Magnoliids, monocots and eudicots) and from different growth forms (trees, erect herbs and rosette herbs). Key Results For all five species, the length-times-width equation explained within-species variation of total leaf area of a shoot with high accuracy (R 2 > 0.994). These strong relationships existed despite leaf dimensions scaling very differently between species. We also found good support for all derived predictions from the model (R 2 > 0.85). Conclusions Our model can be incorporated to improve previous models of allometry that do not consider within-shoot size variation of individual leaves, providing a cross-scale linkage between individual leaf-size variation and shoot-size variation. [ABSTRACT FROM AUTHOR]

Premise: Leaf mass per area (LMA), which is an important functional trait in leaf economic spectrum and plant growth analysis, is measured from leaf discs or whole leaves. Differences between the measurement methods may lead to large differences in the estimates of LMA values. Methods: We examined to what extent estimates of LMA based on whole leaves match those based on discs using 334 woody species from a wide range of biomes (tropics, subtropics, savanna, and temperate), whether the relationship varied by leaf morphology (tissue density, leaf area, leaf thickness), punch size (0.6‐ and 1.0‐cm diameter), and whether the extent of intraspecifc variation for each species matches. Results: Disc‐based estimates of species mean LMA matched the whole‐leaf estimates well, and whole‐leaf LMA tended to be 9.69% higher than leaf‐disc LMA. The ratio of whole‐leaf LMA to leaf‐disc LMA was higher for species with higher leaf tissue density and larger leaves, and variance in the ratio was greater for species with lower leaf tissue density and thinner leaves. Estimates based on small leaf discs also inflated the ratio. The extent of the intraspecific variation only weakly matched between whole‐leaf and disc‐based estimates (R2 = 0.08). Conclusions: Our results suggest that simple conversion between whole‐leaf and leaf‐disc LMA is difficult for species obtained with a small leaf punch, but it should be possible for species obtained with a large+ leaf punch. Accurately representing leaf traits will likely require careful selection between leaf‐disc and whole‐leaf traits depending on the objectives. Quantifying intraspecific variation using leaf discs should be also considered with caution. [ABSTRACT FROM AUTHOR]

Forage yield is largely dependent on leaf development, during which the number of leaves, leaflets, leaf size, and shape are determined. In this mini-review, we briefly summarize recent studies of leaf development in Medicago truncatula, a model plant for legumes, with a focus on factors that could affect biomass of leaves. These include: floral development and related genes, lateral organ boundary genes, auxin biosynthesis, transportation and signaling genes, and WOX related genes. [ABSTRACT FROM AUTHOR]

Despite its importance for crop water use and productivity, especially in drought‐affected environments, the underlying mechanisms of variation in intrinsic water‐use efficiency (iWUE = net photosynthesis/stomatal conductance for water vapour, gsw) are not well understood, especially in C4 plants. Recently, we discovered that leaf width (LW) correlated negatively with iWUE and positively with gsw across several C4 grasses. Here, we confirmed these relationships within 48 field‐grown genotypes differing in LW in Sorghum bicolor, a C4 crop adapted to dry and hot conditions. We measured leaf gas exchange and modelled leaf energy balance three times a day, alongside anatomical traits as potential predictors of iWUE. LW correlated negatively with iWUE and stomatal density, but positively with gsw, interveinal distance of longitudinal veins, and the percentage of stomatal aperture relative to maximum. Energy balance modelling showed that wider leaves needed to open their stomata more to generate a more negative leaf‐to‐air temperature difference, especially at midday when air temperatures exceeded 40°C. These results highlight the important role that LW plays in shaping iWUE through coordination of vein and stomatal traits and by affecting stomatal aperture. Therefore, LW could be used as a predictor of higher iWUE among sorghum genotypes. Summary statement: Leaf width (LW) plays an important role in shaping intrinsic water‐use efficiency (iWUE) across Sorghum bicolor genotypes through coordination of vein and stomatal traits and by regulating stomatal aperture. Wider leaves had higher gsw likely to prevent a detrimental rise in leaf temperature. Therefore, LW could be used as a predictor for higher iWUE among sorghum genotypes [ABSTRACT FROM AUTHOR]

Leaves are enormously diverse in their size and venation architecture, both of which are core determinants of plant adaptation to environments. Leaf size is an important determinant of leaf function and ecological strategy, while leaf venation, the main structure for support and transport, determines the growth, development, and performance of a leaf. The scaling relationship between venation architecture and leaf size has been explored, but the relationship within a community and its potential variations among species with different vein types and leaf habits have not been investigated. Here, we measured vein traits and leaf size across 39 broad-leaved woody species within a subtropical forest community in China and analyzed the scaling relationship using ordinary least squares and standard major axis method. Then, we compared our results with the global dataset. The major vein density, and the ratio of major (1° and 2°) to minor (3° and higher) vein density both geometrically declined with leaf size across different vein types and leaf habits. Further, palmate-veined species have higher major vein density and a higher ratio of major to minor vein density at the given leaf size than pinnate-veined species, while evergreen and deciduous species showed no difference. These robust trends were confirmed by reanalyzing the global dataset using the same major vein classification as ours. We also found a tradeoff between the cell wall mass per vein length of the major vein and the major vein density. These vein scaling relationships have important implications on the optimization of leaf size, niche differentiation of coexisting species, plant drought tolerance, and species distribution. [ABSTRACT FROM AUTHOR]

Leaf size is an important agronomic trait directly affecting yield in rice, and thus understanding the genes determining leaf size is important in breeding. In this study, one Leaf Mutant 7 (lm7) with small leaf size was isolated using ethyl methane sulphonate (EMS) mutagenesis from the japonica Zhenggeng 1925. MutMap by whole genome resequencing of phenotypic bulks revealed that LM7 is likely located in the 133 kb region on chromosome 7 using F2 population from a cross between lm7 and wild-type (WT) Zhenggeng 1925. The candidate gene encoding heat shock protein OsHSP40 for LM7 was functionally validated. Disruption of this gene in Oshsp40 mutants significantly reduced the leaf size compared with that of WT in rice. Microscopic examination showed that OsHSP40 modulated leaf size via regulating the veins formation and cell size/cell number. Nucleotide diversity analysis indicated that a single nucleotide polymorphism (SNP) variation of C to T in the coding region of OsHSP40 may cause small leaves among rice accessions. Therefore, the natural variation of OsHSP40 contributing to leaf size might be useful for rice breeding. [ABSTRACT FROM AUTHOR]

Leafy mistletoes are semi-parasitic plants that have negative impacts on their hosts, but there is inadequate knowledge about the impacts of Loranthus europaeus Jacq. on Persian oak trees (Quercus brantii Lindl.). This study examined the impacts of L. europaeus Jacq. on morphological and physiological characteristics of Persian oak tree leaves in western Iran. A forested area infested with L. europaeus Jacq. was selected to study. Five infected and five healthy Persian oak trees were selected. Leaf samples were collected from the southern side of infected and healthy tree crowns to quantify and compare the leaf area, leaf weight, and concentrations of leaf minerals. The area and weight of leaves and the amount of leaf K, P, and Ca in healthy trees were statistically more than in infected trees. Leaf N, Mg, Mn, Zn, and Fe contents were not significantly different between healthy and infected trees. The higher amount of leaf area and weight in healthy trees suggested that they had a better growing status, which increased their leaf size and weight. The higher concentrations of K and P in healthy trees indicated their greater growth and resistance to stresses such as mistletoe. Thus, mistletoe causes physiological disorders and decreased growth in oak trees. [ABSTRACT FROM AUTHOR]

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CO2 is currently a growth-limiting resource for plants with C3 metabolism, and elevated CO2 also often reduces stomatal conductance, reducing plant water stress. Increased photosynthesis and improved water status might be expected to result in increased leaf size. It is therefore unexpected that leaf size is in some cases reduced in plants grown at elevated CO2, and also unexpected that elevated CO2 applied only during darkness can increase leaf size. These experiments compared leaf size responses to day and/or night elevated CO2 in six cultivars of Phaseolus vulgaris grown with either constant or varying temperature in controlled environment chambers. Diverse responses of leaf size to elevated CO2 were found among the cultivars, including increased leaf size with elevated CO2 applied only during darkness in some cultivars and temperature regimes. However, leaf size responses to elevated CO2 and cultivar differences in response were unrelated to differences in leaf water potential or turgor pressure. [ABSTRACT FROM AUTHOR]

Developmental stability, canalization, and phenotypic plasticity are the most common sources of phenotypic variation, yet comparative studies investigating the relationships between these sources, specifically in plants, are lacking. To investigate the relationships among developmental stability or instability, developmental variability, canalization, and plasticity in plants, we conducted a field experiment with Abutilon theophrasti, by subjecting plants to three densities under infertile vs. fertile soil conditions. We measured the leaf width (leaf size) and calculated fluctuating asymmetry (FA), coefficient of variation within and among individuals (CVintra and CVinter), and plasticity (PIrel) in leaf size at days 30, 50, and 70 of plant growth, to analyze the correlations among these variables in response to density and soil conditions, at each of or across all growth stages. Results showed increased density led to lower leaf FA, CVintra, and PIrel and higher CVinter in fertile soil. A positive correlation between FA and PIrel occurred in infertile soil, while correlations between CVinter and PIrel and between CVinter and CVintra were negative at high density and/or in fertile soil, with nonsignificant correlations among them in other cases. Results suggested the complexity of responses of developmental instability, variability, and canalization in leaf size, as well as their relationships, which depend on the strength of stresses. Intense aboveground competition that accelerates the decrease in leaf size (leading to lower plasticity) will be more likely to reduce developmental instability, variability, and canalization in leaf size. Increased developmental instability and intra‐ and interindividual variability should be advantageous and facilitate adaptive plasticity in less stressful conditions; thus, they are more likely to positively correlate with plasticity, whereas developmental stability and canalization with lower developmental variability should be beneficial for stabilizing plant performance in more stressful conditions, where they tend to have more negative correlations with plasticity. [ABSTRACT FROM AUTHOR]

Leaf morphology is at a certain level defined by the ways in which plants adapt to different habitats, especially in large trees. In this study, morphological variations in leaf size and shape of the Hungarian oak (Quercus frainetto Ten.) growing on different soil types (lithic leptosol, vertisol, cambisol) were investigated in the central part of Serbia (Šumadija). The information on soil type was obtained using a digitalized soil map of the Republic of Serbia, while leaf traits were characterized by geometric morphometric methods. Landmark analysis and leaf measurements showed significant differences among the analyzed groups, with individuals growing on nutrient-poor, shallow soils having smaller leaves with greater lobation. The observed differences suggest that the levels of soil productivity influence variations in leaf patterns. More studies on a larger sample size and along a broader spatial scale are needed to fully understand the differences in the patterns of leaf morphological variation in Q. frainetto. [ABSTRACT FROM AUTHOR]

Premise of research. How vegetation adapts to environmental changes is one of the most important questions in plant science. Temperature and precipitation are considered the main climatic drivers of morphological variations in vegetation. Several studies have demonstrated that leaf morphology varies reliably with increasing latitude, and this is mostly attributed to changes in temperature and precipitation patterns. The morphological responses of plants to temperature and rainfall regimes in arid lands are still scarcely known and understood. We analyze the morphological variation in leaf traits (size and shape) as well as the internode distance in the species Larrea divaricata and their relationship with bioclimatic variables along a latitudinal gradient in central western Argentina. Methodology. We combined a set of morphological features and bioclimatic indexes using multivariate statistics and detected six relevant regions with clear differences in both plant morphology and climatic variables. Pivotal results. The largest foliar areas were located in sites with higher seasonal precipitation. Leaf shape was influenced by temperature, and the internode distances were larger under semihumid conditions. Conclusions. The plant traits of L. divaricata were influenced by the latitudinal gradient and the predominant climate conditions of each recognized region. The study of foliar morphology allowed us to identify environmental factors that potentially influenced morphological responses in the studied species. As a preliminary stage in our research, our contribution attempts to recognize woody plant adaptations to climate influence. Other environmental variables must be included in future work for a more complete analysis. [ABSTRACT FROM AUTHOR]

Plant vigor is a complex trait for which the underlying molecular control mechanisms remain unclear. Vigorous plants tend to derive from larger seeds and have greater early canopy cover, often with bigger leaves. In this study, we delimited the size of a major vigor quantitative trait locus (QTL) on chickpea chromosome 4–104.4 kb, using recombinant association analysis in 15 different heterogeneous inbred families, derived from a Rupali/Genesis836 recombinant inbred line population. The phenotypic and molecular genetic analysis provided evidence for a role of the gene Ca4_TIFY4B , in determining leaf and seed size in chickpea. A non-synonymous single-nucleotide polymorphism (SNP) in the high-vigor parent was located inside the core motif TIFYCG, resulting in a residue change T[I/S]FYCG. Complexes formed by orthologs of Ca4_TIFY4B (PEAPOD in Arabidopsis), Novel Interactor of JAZ (CaNINJA), and other protein partners are reported to act as repressors regulating the transcription of downstream genes that control plant organ size. When tested in a yeast 2-hybrid (Y2H) assay, this residue change suppressed the interaction between Ca4_TIFY4B and CaNINJA. This is the first report of a naturally occurring variant of the TIFY family in plants. A robust gene-derived molecular marker is available for selection in chickpea for seed and plant organ size, i.e., key component traits of vigor. [ABSTRACT FROM AUTHOR]