Plant Leaf Size Research Articles

RING/U-box E3 protein BIR1 interacts with and ubiquitinates barley growth repressor BROAD LEAF1.

Establishment of final leaf size in plants relies on the precise regulation of 2 interconnected processes, cell division and cell expansion. The barley (Hordeum vulgare) protein BROAD LEAF1 (BLF1) limits cell proliferation and leaf growth in the width direction. However, how the levels of this potent repressor of leaf growth are controlled remains unclear. Here, we used a yeast 2-hybrid screen to identify the BLF1-INTERACTING RING/U-BOX 1 (BIR1) E3 ubiquitin ligase that interacts with BLF1 and confirmed the interaction of the 2 proteins in planta. Inhibiting the proteasome caused overaccumulation of a BLF1-eGFP fusion protein when co-expressed with BIR1, and an in vivo ubiquitination assay in bacteria confirmed that BIR1 can mediate ubiquitination of BLF1 protein. Consistent with regulation of endogenous BLF1 in barley by proteasomal degradation, inhibition of the proteasome in BLF1-vYFP-expressing barley plants caused an accumulation of the BLF1 protein. The BIR1 protein co-localized with BLF1 in nuclei and appeared to reduce BLF1 protein levels. Analysis of bir1-1 knockout mutants suggested the involvement of BIR1 in leaf growth control, although mainly on leaf length. Together, our results suggest that proteasomal degradation, in part mediated by BIR1, helps fine-tune BLF1 protein levels in barley.

The Kazakh University Common Bean Collection: The Introductory Trial of Snaps

The aim of the present investigation was to determine the introduction power of the three snap common bean cultivars from the UK in the mountainous zone of Almaty Region in 2023. The harvest-time, plant and leaf growth dynamics, the state of leaf trichomes together with the productivity of snaps at the technical maturity were identified. Cultivars “Amethyst” and “Seline” were shown to be the appropriate snap breeding donors for local bush bean lines due to their parameters of seed germination and plant leaf size together with their trichome parameters resembling those of domestic lines under the study.

Genome-wide identification of GROWTH-REGULATING FACTORs in Liriodendron chinense and functional characterization of LcGRF2 in leaf size regulation

GROWTH-REGULATING FACTORs (GRFs) play a pivotal role in the regulation of leaf size in plants and have been widely reported in plants. However, their specific functions in leaf size regulation in Liriodendron chinense remains unclear. Therefore, in this study, we identified GRF genes on a genome-wide scale in L. chinense to characterize the roles of LcGRFs in regulating leaf size. A total of nine LcGRF genes were identified, and these genes exhibited weak expression in mature leaves but strong expression in shoot apex. Notably, LcGRF2 exhibited the highest expression level in the shoot apex of L. chinense. Further RT-qPCR assay revealed that the expression level of LcGRF2 gradually decreased along with the leaf development process, and also displayed a gradient along the leaf proximo-distal and medio-lateral axes. Furthermore, overexpression of LcGRF2 in Arabidopsis thaliana resulted in increased leaf size, and significantly up-regulated the expression of genes involved in cell division like AtCYCD3;1, AtKNOLLE, and AtCYCB1;1, indicating that LcGRF2 may influence leaf size by promoting cell proliferation. This work contributes to a better understanding of the roles and molecular mechanisms of LcGRFs in the regulation of leaf size in L. chinense.

Yearly weather variation and surface temperature drives the spatiotemporal dynamics of a threatened butterfly and its host plant

It remains unclear to what extent yearly weather variation and spatial variation in microclimate influences the outcome of interacting plant-animal species and whether responses differ between life stages. We collected data over several years on 46 ha on File Hajdar, Gotland, Sweden, and executed a complete mapping of larva nests (n= 776) and imago (n= 5,952) of the marsh fritillary butterflyEuphydryas auriniaand its host plantSuccisa pratensis. The phenology of the butterflies and the major nectar plants visited varied among years. The duration of the adult flight period decreased with increasing ambient air temperatures. The density of butterflies, host plants, and host plant leaf size increased between years with increasing precipitation in the preceding year, and decreased with increasing average ambient air temperature in the preceding year. In 2021–2022 we deployed a unmanned aerial vehicle (UAV) with a high-resolution thermal sensor to measure spatial variation in surface temperatures in the study area. We found that survival from the egg to the larva stage increased with increasing surface temperature and host plant density. Host plants and larva nests generally occupied warmer microhabitats compared to imago butterflies. The results further suggested that the relationships linking surface temperature to the densities of imago, larva, host plants, and leaf size differed qualitatively between years. In 2017, larva nests and host plant density increased with increasing surface temperatures, and butterflies showed a non-linear response with a density peak at intermediate temperatures. As a result of the extreme drought in 2018 there was a reduction in maximum leaf size, and in the densities of plants, larvae, and butterflies. Moreover, the slopes of the relationships linking the density of larvae, butterflies, and plants to temperature shifted from linear positive to negative or curvilinear. Our findings demonstrate how yearly weather variation and heterogeneous surface temperatures can drive the spatiotemporal distribution and dynamics of butterflies and their host plants. The context specificity of the responses indicated by our results makes it challenging to project how climate change will affect the dynamics of ecological communities.

Continuous inbreeding affects genetic variation, phenology, and reproductive strategy in ex situ cultivated Digitalis lutea.

Ex situ cultivation is important for plant conservation, but cultivation in small populations may result in genetic changes by drift, inbreeding, or unconscious selection. Repeated inbreeding potentially influences not only plant fitness, but also floral traits and interactions with pollinators, which has not yet been studied in an ex situ context. We studied the molecular genetic variation of Digitalis lutea from a botanic garden population cultivated for 30 years, a frozen seed bank conserving the original genetic structure, and two current wild populations including the source population. In a common garden, we studied the effects of experimental inbreeding and between-population crosses on performance, reproductive traits, and flower visitation of plants from the garden and a wild population. Significant genetic differentiation was found between the garden population and the wild population from which the seeds had originally been gathered. After experimental selfing, inbreeding depression was only found for germination and leaf size of plants from the wild population, indicating a history of inbreeding in the smaller garden population. Moreover, garden plants flowered earlier and had floral traits related to selfing, whereas wild plants had traits related to attracting pollinators. Bumblebees visited more flowers of outbred than inbred plants and of wild than garden plants. Our case study suggests that high levels of inbreeding during ex situ cultivation can influence reproductive traits and thus interactions with pollinators. Together with the effects of genetic erosion and unconscious selection, these changes may affect the success of reintroductions into natural habitats.

Plant growth and phytoactive alkaloid synthesis in kratom [Mitragyna speciosa (Korth.)] in response to varying radiance.

Leaves harvested from kratom [Mitragyna speciosa (Korth.)] have a history of use as a traditional ethnobotanical medicine to combat fatigue and improve work productivity in Southeast Asia. In recent years, increased interest in the application and use of kratom has emerged globally, including North America, for its potential application as an alternative source of medicine for pain management and opioid withdrawal syndrome mitigation. Although the chemistry and pharmacology of major kratom alkaloids, mitragynine and 7-hydroxymitragynine, are well documented, foundational information on the impact of plant production environment on growth and kratom alkaloids synthesis is unavailable. To directly address this need, kratom plant growth, leaf chlorophyll content, and alkaloid concentration were evaluated under three lighting conditions: field full sun (FLD-Sun), greenhouse unshaded (GH-Unshaded), and greenhouse shaded (GH-Shaded). Nine kratom alkaloids were quantified using an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Greenhouse cultivation generally promoted kratom height and width extension by 93–114% and 53–57%, respectively, compared to FLD-Sun. Similarly, total leaf area and leaf number were increased by 118–160% and 54–80% under such conditions. Average leaf size of plants grown under GH-Shaded was 41 and 69% greater than GH-Unshaded and FLD-Sun, respectively; however, no differences were observed between GH-Unshaded and FLD-Sun treatments. At the termination of the study, total leaf chlorophyll a+b content of FLD-Sun was 17–23% less than those grown in the greenhouse. Total leaf dry mass was maximized when cultivated in the greenhouse and was 89–91% greater than in the field. Leaf content of four alkaloids to include speciociliatine, mitraphylline, corynantheidine, and isocorynantheidine were not significantly impacted by lighting conditions, whereas 7-hydroxymitragynine was below the lower limit of quantification across all treatments. However, mitragynine, paynantheine, and corynoxine concentration per leaf dry mass were increased by 40%, 35%, and 111%, respectively, when cultivated under GH-Shaded compared to FLD-Sun. Additionally, total alkaloid yield per plant was maximized and nearly tripled for several alkaloids when plants were cultivated under such conditions. Furthermore, rapid, non-destructive chlorophyll evaluation correlated well (r2 = 0.68) with extracted chlorophyll concentrations. Given these findings, production efforts where low-light conditions can be implemented are likely to maximize plant biomass and total leaf alkaloid production.

Environmental filtering rather than phylogeny determines plant leaf size in three floristically distinctive plateaus

Leaf is essential for plant growth and development; however, the relative importance of environmental filtering and phylogeny in determining leaf size across different spatial scales in grassland ecosystems remains poorly explored. We used transect methodology to explore the spatial variation in leaf size and its underlying mechanisms in grasslands along three topographically and floristically distinctive plateaus in northern China. We measured leaf size of a total of 1192 grassland species in the Tibetan Plateau (TP, temperature limited), Loess Plateau (LP, soil-nutrient limited), and Mongolia Plateau (MP, precipitation limited) along three transects encompassing meadow, typical, and desert steppes. Leaf size ranged from 0.01 to 258.16 cm2, with an average of 5.54 cm2. The smallest leaves were measured in the TP. At the vegetation association level, the largest leaves were present in the meadow steppe, followed by those in typical and desert steppes, irrespective of the plateau. Unexpectedly, phylogeny had a negligible effect on the spatial variation in leaf size in the grasslands. Leaf size was positively correlated with growing-season temperature and precipitation but negatively correlated with ultraviolet (UV) radiation, suggesting that environmental filtering plays a more important role in affecting leaf size than phylogeny. Furthermore, leaf size in the TP and MP was mainly affected by precipitation and UV radiation, respectively, whereas that in the LP was affected by temperature, precipitation, soil nutrients and UV light. Specifically, our results underscored the importance of environmental filtering rather than phylogeny in determining plant leaf size and shed light on the unexpected role of UV radiation in contributing to leaf size variations in these plateaus. Our study provides novel insights into the response of plants to global change, especially in plateaus, alpine zone, and high-latitude areas.

Trade-off relationship and internal mechanism of plant leaf size and number in Hulunbuir grassland, China.

The trade-off between leaf size and number is the basis for plant growth strategies. It is of great significance to study the underlying mechanism of leaf size and number trade-offs for well understanding plant growth strategies. In this study, leaf size was expressed by the dry mass of single leaf, while leafing intensity was expressed by the number of leaves per unit stem volume. We used standardized major axis regression analysis method to examine the trade-off relationship between leaf size and number in Hulunbuir grassland. There was a significant negative isometric-growth trade-off between leaf size and number in Chenqicuogang (typical steppe) and Chenqibayi (meadow steppe). There was a significant negative allometric-growth trade-off between leaf size and number in Xeltala (meadow steppe). The underlying mechanism of the relationship between leaf size and number depended on the leaf and stem biomass allocation mechanism and the changes of the stem tissue density.

Changes in the Morphological Characteristics of Potato Plants Attributed to Seasonal Variability

The development of a potato crop differs according to the environmental conditions and growing season of an area. Periods of high temperatures and drought have been frequent in recent years, and this has affected crops worldwide. The effect of meteorological factors on the plant morphology of potato cultivars growing in A Limia was analyzed for three consecutive years. The crop cycle with the highest temperatures and least accumulated rainfall (2016) showed plants with a higher number of leaflets, which were shorter in length. The crop cycle (2014) with a lower temperature and more rainfall had the tallest plants, the highest degree of flowering, fewer pairs of leaflets and the highest length of the floral peduncle. Kennebec and Fontane were the varieties that showed the least variability in morphological characteristics during the seasons analyzed. Considering the meteorological and morphological data, a principal component analysis was carried out, which explained 80.1% of the variance of the data. Spearman rank correlations showed higher significant coefficients between the temperature and foliar characteristics. The leaf size of plants was estimated using a multiple linear regression analysis, which included the mean temperature, explaining 64% of the variability of the data.

Leaf size, climate, and energy balance

Plant Ecology Why does plant leaf size increase at lower latitudes, as exemplified by the evolutionary success of species with very large leaves in the tropics? Wright et al. analyzed leaf data for 7670 plant species, along with climatic data, from 682 sites worldwide. Their findings reveal consistent patterns and explain why earlier predictions from energy balance theory had only limited success. The authors provide a fully quantitative explanation for the latitudinal gradient in leaf size, with implications for plant ecology and physiology, vegetation modeling, and paleobotany. Science , this issue p. [917][1] [1]: /lookup/doi/10.1126/science.aal4760

Global climatic drivers of leaf size.

Leaf size varies by over a 100,000-fold among species worldwide. Although 19th-century plant geographers noted that the wet tropics harbor plants with exceptionally large leaves, the latitudinal gradient of leaf size has not been well quantified nor the key climatic drivers convincingly identified. Here, we characterize worldwide patterns in leaf size. Large-leaved species predominate in wet, hot, sunny environments; small-leaved species typify hot, sunny environments only in arid conditions; small leaves are also found in high latitudes and elevations. By modeling the balance of leaf energy inputs and outputs, we show that daytime and nighttime leaf-to-air temperature differences are key to geographic gradients in leaf size. This knowledge can enrich "next-generation" vegetation models in which leaf temperature and water use during photosynthesis play key roles.

Sugar export limits size of conifer needles.

Plant leaf size varies by more than three orders of magnitude, from a few millimeters to over one meter. Conifer leaves, however, are relatively short and the majority of needles are no longer than 6 cm. The reason for the strong confinement of the trait-space is unknown. We show that sugars produced near the tip of long needles cannot be exported efficiently, because the pressure required to drive vascular flow would exceed the greatest available pressure (the osmotic pressure). This basic constraint leads to the formation of an inactive region of stagnant fluid near the needle tip, which does not contribute to sugar flow. Remarkably, we find that the size of the active part does not scale with needle length. We predict a single maximum needle size of 5 cm, in accord with data from 519 conifer species. This could help rationalize the recent observation that conifers have significantly smaller leaves than angiosperms, and provide a biophysical explanation for this intriguing difference between the two largest groups of plants.

The tiny-leaved orchid Cephalanthera subaphylla obtains most of its carbon via mycoheterotrophy.

The evolution of mycoheterotrophy has been accompanied by extreme reductions in plant leaf size and photosynthetic capacity. Partially mycoheterotrophic plants, which obtain carbon from both photosynthesis and their mycorrhizal fungi, include species with leaves of normal size and others that are tiny-leaved. Thus, plant species may lose their leaves in a gradual process of size reduction rather than through a single step mutation. Little is known about how the degree of mycoheterotrophy changes during reductions in leaf size. We compared the degree of mycoheterotrophy among five Japanese Cephalanthera species, four with leaves of normal size (Cephalanthera falcata, Cephalanthera erecta, Cephalanthera longibracteata and Cephalanthera longifolia), one with tiny leaves (Cephalanthera subaphylla), and one albino form of C. falcata (as reference specimens for fully mycoheterotrophic plants). The levels of mycoheterotrophy were determined by stable isotope natural abundance analysis. All Cephalanthera species were relatively enriched in 13C and 15N in comparison with surrounding autotrophic plants. Cephalanthera subaphylla was strongly enriched in 13C and 15N to levels similar to the albinos. Species with leaves of normal size were significantly less enriched in 13C than C. subaphylla and the albinos. Thus, C. subaphylla was strongly mycoheterotrophic, obtaining most of its carbon from mycorrhizal fungi even though it has tiny leaves; species with leaves of normal size were partially mycoheterotrophic. Hence, during the evolutionary pathway to full mycoheterotrophy, some plant species appear to have gained strong mycoheterotrophic abilities before completely losing foliage leaves.

Influence of leaf size of plant on leaf transpiration and temperature in arid regions

Aims Our objective was to demonstrate the influence of leaf size on leaf transpiration and temperature in arid regions. Methods Based on energy and material exchange theory and the results of previous studies, we set up a single leaf energy and material exchange model combined with arid environmental conditions. Important findings Leaf transpiration decreased with increasing stomatal resistance, but leaf temperature increased. Leaf transpiration and temperature decreased with decreasing leaf radiation absorption rate in the same environmental conditions. Moreover, leaf width and wind speed were important parameters in understanding leaf energy and material exchange. Leaf transpiration and temperature generally decreased with decreasing leaf width with wind speed 0.1 m·s –1 and stomatal resistance about 1 000 s·m –1 . Low leaf transpiration and temperature could encourage plant growth with the low water availability, high radiation and high temperature conditions in arid regions.

Influence of leaf size of plant on leaf transpiration and temperature in arid regions

Influence of leaf size of plant on leaf transpiration and temperature in arid regions

Influence of Genetic Variation on Morphological Diversity in Accessions of Stevia Rebaudiana Bertoni

Stevia rebaudiana, a non caloric natural sweetener is currently the available substitute to sugar. It is a genus of about 150 species of herbs and shrubs, a Compositae and a native to Paraguay. The aim of this study was to evaluate collected accessions of stevia and characterize their genetic divergence. In 2010, 10 stevia accessions were collected across different locations in Malaysia. At maturity they were evaluated using morphological parameters and collected data were subjected to‘t’ test analysis at p<.05 as follows-(i) Plant heights: MS012 & SBK were significant at p<.001 and p<.002 respectively. (ii) Number of branches: BGI & SBK were significant at p<.001 and p<.008 respectively.(iii) Number of corymbs: AZI was significant at p<.000, while BGI was significant at p<.033. (iv) Number of leaves: MS012 & MS007 were respectively significant at p<.000 and p<.008. (v) Plant leaf size: AZI was significant at p<.003, MS007 at p<.005, and MS012 at p<.019 and (vi) stem girth: MS012 & MRG were also significantly different at p<.000 and p<.001 respectively. MSO12, MS007 & SBK had loads of promising genetic traits in studied accessions.

A size‐mediated effect can compensate for transient chilling stress affecting maize (Zea mays) leaf extension

*In this study, we examined the impact of transient chilling in maize (Zea mays). We investigated the respective roles of the direct effects of stressing temperatures and indirect whorl size-mediated effects on the growth of leaves chilled at various stages of development. *Cell production, individual leaf extension and final leaf size of plants grown in a glasshouse under three temperature regimes (a control and two short chilling transfers) were studied using two genotypes contrasting in terms of their architecture. *The kinetics of all the leaves emerging after the stress were affected, but not all final leaf lengths were affected. No size-mediated propagation of an initial growth reduction was observed, but a size-mediated effect was associated with a longer duration of leaf elongation which compensated for reduced leaf elongation rates when leaves were stressed during their early growth. Both cell division and cell expansion contributed to explaining cold-induced responses at the leaf level. *These results demonstrate that leaf elongation kinetics and final leaf length are under the control of processes at the n - 1 (cell proliferation and expansion) and n + 1 (whorl size signal) scales. Both levels may respond to chilling stress with different time lags, making it possible to buffer short-term responses.

A role for leaf epidermis in the control of leaf size and the rate and extent of mesophyll cell division

Little is known about the control of leaf size in plants, yet there must be mechanisms by which organ size is measured. Because the control of leaf size extends beyond the action of individual genes or cells, an understanding of the role of leaf cell layers in the determination of leaf size is warranted. Following the construction of graft chimeras composed of small- and large-leaf genotypes of Nicotiana, bilateral leaf blade asymmetry was observed on leaves possessing either a genetically larger or smaller epidermis on one side of the midrib. Although cell size was unaffected by the genotype of the epidermis, the rate and extent of cell division in leaf epidermis altered the rate and extent of cell division in mesophyll and affected leaf size. The data presented neither prove nor disprove whether the mesophyll impacts epidermal cell division but provide the first unequivocal evidence that the extent of cell division in the leaf epidermis alters the extent of cell division in the mesophyll and is a factor regulating blade expansion and ultimate leaf size.

BOLITA, an Arabidopsis AP2/ERF-like transcription factor that affects cell expansion and proliferation/differentiation pathways

The BOLITA (BOL) gene, an AP2/ERF transcription factor, was characterized with the help of an activation tag mutant and overexpression lines in Arabidopsis and tobacco. The leaf size of plants overexpressing BOL was smaller than wild type plants due to a reduction in both cell size and cell number. Moreover, severe overexpressors showed ectopic callus formation in roots. Accordingly, global gene expression analysis using the overexpression mutant reflected the alterations in cell proliferation, differentiation and growth through expression changes in RBR, CYCD, and TCP genes, as well as genes involved in cell expansion (i.e. expansins and the actin remodeling factor ADF5). Furthermore, the expression of hormone signaling (i.e. auxin and cytokinin), biosynthesis (i.e. ethylene and jasmonic acid) and regulatory genes was found to be perturbed in bol-D mutant leaves.

DETERMINATION OF LEAF AREA AND PLANT COVER BY USING DIGITAL IMAGE PROCESSING

The development of different crop models, and crop simulation models in particular, pointed out the importance of quantifying the exact value of the leaf area. To measure the leaf size of plants of pinnatifid form, automatic, portable leaf area meters are necessary. In most places these instruments are not available to measure the assimilatory surface size of crops with special leaf shapes. Any cheap and effective method, that could replace the application of expensive portable area meters could be useful in practical every-day research. A CCD camera was applied in our study to take photos in every leaf level of plant height. Another problem is the determination of the shadowing surface (covering) of the whole plant one at a time. By analyzing the images the leaf area or the covering of a whole plant was evaluated.