Variation In Leaf Area Research Articles

Effects of Leafy Flexible Vegetation on Bed‐Load Transport and Dune Geometry

AbstractThe development of sustainable river management strategies requires knowledge of the effect of vegetation on hydrodynamics and sediment transport. To date, the complex physical processes involving the combined effects of leafy flexible vegetation and mobile bedforms are not completely understood. Most sediment transport models have been developed for bare bed conditions so that their performance in the presence of leafy flexible vegetation remains unclear. On the other hand, recently developed models consider vegetated conditions but they typically account only for the presence of rigid cylinders and in some cases scour at their base. For this purpose, laboratory experiments were conducted with mobile dune bed conditions and artificial flexible plants with varying Leaf Area Index to investigate the effect of flexible vegetation on bed morphology and sediment transport. Sediment transport rates and bedform characteristics such as height, wavelength and celerity, were measured in specifically designed experimental runs. The collected data show that the presence of leafy vegetation alters bed morphology, tending to reduce the average dune wavelength and leading to the formation of complex 3D geometries. Bed‐shear‐stress‐based models for predicting sediment transport were verified to be valid under conditions of low vegetation roughness density. On the contrary, the collected data emphasize that the measured bed‐load transport rate increased in the presence of leafy flexible vegetation with higher frontal area. Recent bed‐load models for vegetated channels provide a better interpretation for dense leafy vegetation but are less effective when predominant effects related to dunes are present.

Intraspecific variation in leaf morphology of three widespread woody species along climatic gradients

Abstract The variation and plasticity of leaf morphology plays a pivotal role in the response to environmental changes for plant individuals. Discovering the large-scale pattern of such variation can reveal plants' general adaptive strategies. We analyzed leaf morphology of three widespread woody species in the northern hemisphere using specimen data from the iDigBio and GBIF databases, to investigate the variations in the individual mean traits, in the inter- and intra-individual variability of traits, and in the allometry between traits, along climatic gradients. We found that larger and wider leaves were associated with warmer, wetter and low-sunlight habitats, while smaller but wider leaves are linked to higher wind speed, indicating the response of leaf morphology to multiple climate stresses. The inter-individual variation in leaf area was smaller in colder and windier conditions, suggesting the trait convergence among individuals under environmental filtering, while the intra-individual variation in leaf relative width was smaller in warmer habitats, indicating the similar growth optimum of leaves within one individual in more favorable conditions. Finally, the allometric exponent between leaf length (X-axis) and width (Y-axis) became greater under lower solar radiation and higher wind speed, while the squared correlation coefficient (r2) indicating phenotypic integration showed a decoupling trend under colder conditions, indicating that climate affected the variation tendency of leaf relative width during leaf enlargement. These results reveal the common patterns of leaf morphology responding to climate variation spatially and underscore the necessity to consider inter- and intra-individual variability when examining plant responses to environmental changes.

Scaling relationships between the total number of leaves and the total leaf area per culm of two dwarf bamboo species.

Total leaf area per plant is an important measure of the photosynthetic capacity of an individual plant that together with plant density drives the canopy leaf area index, that is, the total leaf area per unit ground area. Because the total number of leaves per plant (or per shoot) varies among conspecifics and among mixed species communities, this variation can affect the total leaf area per plant and per canopy but has been little studied. Previous studies have shown a strong linear relationship between the total leaf area per plant (or per shoot) (A T) and the total number of leaves per plant (or per shoot) (N T) on a log-log scale for several growth forms. However, little is known whether such a scaling relationship also holds true for bamboos, which are a group of Poaceae plants with great ecological and economic importance in tropical, subtropical, and warm temperate regions. To test whether the scaling relationship holds true in bamboos, two dwarf bamboo species (Shibataea chinensis Nakai and Sasaella kongosanensis 'Aureostriatus') with a limited but large number of leaves per culm were examined. For the two species, the leaves from 480 and 500 culms, respectively, were sampled and A T was calculated by summing the areas of individual leaves per culm. Linear regression and correlation analyses reconfirmed that there was a significant log-log linear relationship between A T and N T for each species. For S. chinensis, the exponent of the A T versus N T scaling relationship was greater than unity, whereas that of S. kongosanensis 'Aureostriatus' was smaller than unity. The coefficient of variation in individual leaf area increased with increasing N T for each species. The data reconfirm that there is a strong positive power-law relationship between A T and N T for each of the two species, which may reflect adaptations of plants in response to intra- and inter-specific competition for light.

Pengaruh Pemberian Pupuk Hayati Terhadap Pertumbuhan dan Hasil Tanaman Bayam Brazil (Alternanthera sissoo)

ABSTRACT Spinach plant production has decreased every year and the use of inorganic fertilizers is still often used by farmers. The right innovation of Brazilian spinach cultivation technique is by using biological fertilizers. This study used a non-factorial completely randomized design (CRD) with 5 treatment levels repeated 4 times, namely C0: 0 mg/plant (Control), C1: 20 mg/plant, C2: 40 mg/plant, C3: 60 mg /plant, and C4: 80 mg/plant so that there are 20 experimental treatment units. The variables used in this study were plant height, number of leaves, number of branches, leaf area, chlorophyll content, canopy area, and plant fresh weight. The data obtained were analyzed for variance (ANOVA) and further tested with Duncan's Multiple Range Test (DMRT) with a confidence level of 95%. The results showed that there was a significant effect of the application of biological fertilizers on the growth and yield of Brazilian spinach (Althernanthera sisso), namely height plants that produce the highest average value of 24.23 cm, the variable number of branches with the highest value is 6.25 branches, the variable leaf area with the highest value is 131.88 cm2, and the variable number of leaves that gives a very significant different effect with the highest value ie 11.25 strands. The correct dosage of biological fertilizers is found in the Agrice Plus fertilizer treatment with a dose of 80 mg/plant for all observed variables. Keywords:, Brazilian Spinach, Biofertilizer

Morphoanatomy and physiology of Swietenia macrophylla in different light environments: Insights into its invasive ability in the Philippines

Abstract. Agoto Jr. RNA, Hernandez JO, Park BB. 2024. Morphoanatomy and physiology of Swietenia macrophylla in different light environments: Insights into its invasive ability in the Philippines. Biodiversitas 25: 257-263. Evidence supporting Swietenia macrophylla G.King's invasive ability is primarily inferential to date. The present study analyzed the variation in morphoanatomical and physiological traits of the species between shaded and sun-exposed environments to provide insights into its invasive ability in the Philippines. The variations in leaf area, seedling height, leaf pH, biomass, parenchyma and collenchyma cell thickness, lumen area of xylem vessels, stomatal conductance, and leaf relative water content were analyzed between shaded and sun-exposed light conditions. While stem and leaf biomass did not differ between the two light conditions, root biomass was 27% higher in the shaded than in the sun-exposed seedlings. Leaf pH was substantially lower in the shaded than in the sun-exposed condition. The vessel lumen area in both leaf and root was significantly larger in shaded than in sun-exposed condition by 10-15%. The parenchyma of seedlings in the shady area of the forest was thicker (c.a., 1-2 layers) compared to those in the well-lit environment, particularly in the leaf and root. While stomatal conductance was similar between the two light environments, shaded ones had a much larger leaf relative water content, up by 9-12%. Overall, we found significant morphoanatomical and physiological variations between shaded and sun-exposed seedlings, indicating invasive species' light-capture strategy and providing insights into S. macrophylla's invasive potential in the Philippines.

Comparison of five equations in describing the variation of leaf area distributions of Alangium chinense (Lour.) Harms.

Previous studies have validated a performance equation (PE) and its generalized version (GPE) in describing the rotated and right-shifted Lorenz curves of organ size (e.g., leaf area and fruit volume) distributions of herbaceous plants. Nevertheless, there are still two questions that have not been adequately addressed by prior work: (i) whether the PE and GPE apply to woody plant species and (ii) how do the PE and GPE perform in comparison with other Lorenz equations when fitting data. To address these deficiencies, we measured the lamina length and width of each leaf on 60 Alangium chinense saplings to compare the performance of the PE and GPE with three other Lorenz equations in quantifying the inequality of leaf area distributions across individual trees. Leaf area is shown to be the product of a proportionality coefficient (k) and leaf length and width. To determine the numerical value of k, we scanned 540 leaves to obtain the leaf area empirically. Using the estimated k, the leaf areas of 60A. chinense saplings were calculated. Using these data, the two performance equations and three other Lorenz equations were then compared and assessed using the root-mean-square error (RMSE) and Akaike information criterion (AIC). The PE and GPE were found to be valid in describing the rotated and right-shifted Lorenz curves of the A. chinense leaf area distributions, and GPE has the lowest RMSE and AIC values. This work validates the GPE as the best model in gauging variations in leaf area of the woody species.

Climate-related variation in leaf size and phenology of Betula ermanii in multiple common gardens

ABSTRACT Leaf phenology and properties are the vital traits of productivity and fitness of individual trees. Understanding the climatic conditions associated with the trait variation is essential for evaluation of the tree species’ capacity to face and adapt to environmental change. This study focused on the habits of the tree species in the alpine forests where they are experiencing some of the highest rates of warming under recent climate change. Thus, we examined the climate-related variation in leaf area, specific leaf area (SLA) and the timing of bud break in common gardens of Betula ermanii across a wide latitudinal range, as well as their height that was strongly correlated with leaf traits. Based on analysis of variance, all recorded traits were found to be genetically controlled, and leaf area was most strongly affected by genetic factors. Traits of saplings from higher latitudinal populations included taller height, larger leaf area, larger SLA and earlier bud break. Leaf area of B. ermanii saplings was strongly correlated with the height of the saplings, as taller saplings exhibited larger leaves. Saplings derived from regions with fewer precipitation in summer showed taller height and larger leaves. In contrast, we could not observe significant associations between SLA and timing of bud break, and any climatic variable for two experimental years. Increasing earliness of bud break of B. ermanii with increases in latitude was likely to associate with the gradients of photoperiod. Climate gradients between populations seemed to contribute to the geographic variation in the height, leaf and phenological traits of B. ermanii.

Interannual land cover and vegetation variability based on remote sensing data in the HTESSEL land surface model: implementation and effects on simulated water dynamics

Abstract. Vegetation largely controls land surface–atmosphere interactions. Although vegetation is highly dynamic across spatial and temporal scales, most land surface models currently used for reanalyses and near-term climate predictions do not adequately represent these dynamics. This causes deficiencies in the variability of modeled water and energy states and fluxes from the land surface. In this study we evaluated the effects of integrating spatially and temporally varying land cover and vegetation characteristics derived from satellite observations on modeled evaporation and soil moisture in the Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land (HTESSEL) land surface model. Specifically, we integrated interannually varying land cover from the European Space Agency Climate Change Initiative and interannually varying leaf area index (LAI) from the Copernicus Global Land Services (CGLS). Additionally, satellite data on the fraction of green vegetation cover (FCover) from CGLS were used to formulate and integrate a spatially and temporally varying effective vegetation cover parameterization. The effects of these three implementations on model evaporation fluxes and soil moisture were analyzed using historical offline (land-only) model experiments at the global scale, and model performances were quantified with global observational products of evaporation (E) and near-surface soil moisture (SMs). The interannually varying land cover consistently altered the evaporation and soil moisture in regions with major land cover changes. The interannually varying LAI considerably improved the correlation of SMs and E with respect to the reference data, with the largest improvements in semiarid regions with predominantly low vegetation during the dry season. These improvements are related to the activation of soil moisture–evaporation feedbacks during vegetation-water-stressed periods with interannually varying LAI in combination with interannually varying effective vegetation cover, defined as an exponential function of LAI. The further improved effective vegetation cover parameterization consistently reduced the errors of model effective vegetation cover, and it regionally improved SMs and E. Overall, our study demonstrated that the enhanced vegetation variability consistently improved the near-surface soil moisture and evaporation variability, but the availability of reliable global observational data remains a limitation for complete understanding of the model response. To further explain the improvements found, we developed an interpretation framework for how the model development activates feedbacks between soil moisture, vegetation, and evaporation during vegetation water stress periods.

Impact of Updating Vegetation Information on Land Surface Model Performance

AbstractVegetation plays a fundamental role in modulating the exchange of water, energy, and carbon fluxes between the land and the atmosphere. These exchanges are modeled by Land Surface Models (LSMs), which are an essential part of numerical weather prediction and data assimilation. However, most current LSMs implemented specifically in weather forecasting systems use climatological vegetation indices, and land use/land cover data sets in these models are often outdated. In this study, we update land surface data in the European Centre for Medium‐range Weather Forecast (ECMWF) land surface modeling system (ECLand) using Earth observation‐based time varying leaf area index and land use/land cover data, and evaluate the impact of vegetation dynamics on model performance. The performance of the simulated latent heat flux and soil moisture is then evaluated against global gridded observation‐based data sets. Updating the vegetation information does not always yield better model performances because the model's parameters are adapted to the previously employed land surface information. Therefore we recalibrate key soil and vegetation‐related parameters at individual grid cells to adjust the model parameterizations to the new land surface information. This substantially improves model performance and demonstrates the benefits of updated vegetation information. Interestingly, we find that a regional parameter calibration outperforms a globally uniform adjustment of parameters, indicating that parameters should sufficiently reflect spatial variability in the land surface. Our results highlight that newly available Earth‐observation products of vegetation dynamics and land cover changes can improve land surface model performances, which in turn can contribute to more accurate weather forecasts.

Morphoanatomical Responses and Stomatal Conductance in Shaded and Sun-Exposed Broussonetia papyrifera Seedlings

Investigating invasive species’ morphoanatomical characteristics, such as leaf area and thickness of vascular tissues and storage cells, can reveal information about their adaptive ability and competitive advantage. Thus, we analyzed the variation in leaf, stem, and root morphoanatomical structure and stomatal conductance between shaded and sun-exposed seedlings of Broussonetia papyrifera to provide insights into management strategies to control its invasive ability. The variations in leaf area (LA), Leaf Mass per Area (LMA), stomatal density, thickness of palisade and spongy mesophyll tissues, thickness of xylem parenchyma cells, diameter of all xylem vessels in stem and roots and stomatal conductance were analyzed between shaded and sun-exposed seedlings. Results revealed that the LA and LMA of B. papyrifera were significantly larger in the sun-exposed than in the shaded condition. Seedlings exposed to sunlight also had thicker palisade mesophyll and xylem parenchyma cells. The diameter of xylem vessels in roots was also significantly higher in sun-exposed seedlings. Contrarily, a reverse pattern was observed in the diameter of stem xylem vessels (i.e., shaded > sun-exposed seedlings). Physiologically, a higher stomatal conductance was also observed in sun-exposed seedlings. In conclusion, we found significant variations in leaf, stem, and root morphoanatomy and stomatal conductance between shaded and sun-exposed seedlings of B. papyrifera. The findings of the present study may provide valuable implications for managing or controlling its invasibility in the introduced range. Keywords: freehand technique, invasive species, Moraceae, paper mulberry, stomatal conductance

Pengaruh Dosis dan Frekuensi Pemberian Bahan Organik Cair Urine Kelinci terhadap Pertumbuhan dan Hasil Bayam Merah (Amaranthus tricolor L.)

Increasing the production of red spinach can be done through fertilization. This research aimed to know the effect of dose, frequency application, and combination of dose and frequency application of liquid organic fertilizer from rabbit's urine on the growth and yield of red spinach plants. The research was conducted from December 2020 to February 2021 at the screen house in Melung Village, Kedung Banteng District, Banyumas Regency and the Laboratory of Agronomy and Horticulture, Faculty of Agriculture, Jenderal Soedirman University. The research was carried out using polybag experiment in a screen house with 3 x 3 factorial treatment plus control. The experimental design was a Completely Randomized Block Design which resulted in 9 factorial and control treatments, repeated 3 times so that there were 30 experimental units. The first factor was the dose of liquid organic fertilizer from rabbit urine, which consisted of 3 levels, namely 150, 300, and 450 ml/plant. The second factor is the frequency of fertilization time which consists of 3 levels, that is 1x application (5dap), 3x application (5, 10, and 15 dap), and 5x application (5, 10, 15, 20 and 25 dap). Observation variables included plant height, number of leaves, leaf area, fresh plant weight, dry plant weight, fresh root weight, dry root weight, fresh crown weight and waste index. The data obtained were analyzed using the F test. If there was variance, the data was analyzed using the Dunnett test at a 95% confidence level. The dose of 300 ml/plant of liquid organic fertilizer of rabbit urine affected the growth of red spinach seen in the variables of fresh plant weight, dry plant weight, number of leaves, leaf area, and plant height. In addition, the fresh crown weight variable shows the effect on the yield of red spinach. The frequency of 5 times giving liquid organic fertilizer from rabbit urine affects the yield of red spinach seen in the fresh crown weight variable. A good combination was obtained between a dose of 300 ml/plant and a frequency of 5x administration of LOM rabbit urine on the growth of red spinach seen in the variable leaf area and fresh crown weight.

Impacts of landscape patterns on plant species diversity at a global scale

Landscape patterns are important drivers of biodiversity. Owing to differences in vegetation types, sampling methods, diversity measures, spatial scales, and landscape levels, the impact of landscape patterns on biodiversity remains widely debated. Using a global standardized plant community database and land use and land cover maps at 30-m resolution, for the period 1990–2017, we calculated plant species α- and β-diversity, and landscape metrics at patch- and landscape-levels, and discerned the direct and indirect impacts of landscape patterns on plant species diversity based on environmental factors, namely climate, spatial features, and human disturbance. We found that landscape patterns exhibited the main indirect effects, whereas climate factors exhibited dominant direct effects on plant α-diversity via the direct effects of patch patterns and functional traits. With respect to β-diversity, landscape-level patterns exerted more direct than indirect effects. These effects are strongly dependent on scale. Landscape- and patch-level patterns had opposite effects on plant diversity, depending on their composition and spatial structure, demonstrating that their effects could be mediated by one another. The adaptation of plants to landscape patterns is mainly through variations in leaf area, plant height, specific leaf area, stem density, seed biomass, and other seed-dispersal traits, which vary across vegetation types. Our findings highlight the importance of functional traits and diversity in understanding the mechanism by which landscape patterns influence plant species diversity; accordingly, we recommend balancing the spatial structure of patch- and landscape-level patterns to enhance variation in functional traits, and, ultimately, to maintain global plant diversity.

Seed-Specific Mass and Root Growth Relate to Perennial Bunchgrass Seedling Survivorship Under Highly Limited Nutrient Supply

Maternal provisioning to seeds is critical to later plant success, and identifying seed traits that predict successful plant establishment and resilience may facilitate improved plant material selection for rangeland restoration. Although size-standardized measurements are typically recorded for leaf traits, this is not the case for seed traits. In this study, we investigated whether an area-standardized metric, seed-specific mass (SSM), was better associated with seedling performance relative to simple seed mass. We germinated seeds of bluebunch wheatgrass (Pseudoroegneria spicata [Pursh.] A. Löve), crested wheatgrass (Agropyron cristatum L. var. Hycrest II), and Sandberg bluegrass (Poa secunda Presl.) on sterile agar and tracked seed mass, SSM, and subsequent seedling growth and mortality to investigate relationships between seed traits and seedling performance. SSM showed clear variation among species despite similarities in seed mass, and species-specific patterns of mortality most closely tracked variation in SSM. Crested wheatgrass seedlings that survived to 52 wk had significantly greater SSM than those that perished during the study, and surviving seedlings also had significantly longer roots at wk 4 than those that died. Seed mass and SSM each explained variation in seedling traits to some extent. Simple seed mass best predicted variation in early leaf area within species, while root length was best predicted by SSM across species. Our study is indicative that SSM warrants consideration in future studies investigating maternal energetic provisioning and seedling performance.

Assisted migration experiments along a distance/elevation gradient show limits to supporting home site communities

We addressed the hypothesis that intraspecific genetic variation in plant traits from different sites along a distance/elevation gradient would influence the communities they support when grown at a new site. Answers to this hypothesis are important when considering the community consequences of assisted migration under climate change; i.e., if you build it will they come?. We surveyed arthropod communities occurring on the foundation riparian tree speciesPopulusangustifolia along a distance/elevation gradient and in a common garden where trees from along the gradient were planted 20–22 years earlier. Three major patterns were found: 1) In the wild, arthropod community composition changed significantly. Trees at the lower elevation site supported up to 58% greater arthropod abundance and 26% greater species richness than more distant, high elevation trees. 2) Trees grown in a common garden sourced from the same locations along the gradient, supported arthropod communities more similar to their corresponding wild trees, but the similarity declined with transfer distance and elevation. 3) Of five functional traits examined, leaf area, a trait under genetic control that decreases at higher elevations, is correlated with differences in arthropod species richness and abundance. Our results suggest that genetic differences in functional traits are stronger drivers of arthropod community composition than phenotypic plasticity of plant traits due to environmental factors. We also show that variation in leaf area is maintained and has similar effects at the community level while controlling for environment. These results demonstrate how genetically based traits vary across natural gradients and have community-level effects that are maintained, in part, when they are used in assisted migration. Furthermore, optimal transfer distances for plants suffering from climate change may not be the same as optimal transfer distances for their dependent communities.

Shrubs Compensate for Tree Leaf Area Variation and Influence Vegetation Indices in Post‐Fire Siberian Larch Forests

AbstractIn post‐fire Siberian larch forests, where tree density can vary within a burn perimeter, shrubs constitute a substantial portion of the vegetation canopy. Leaf area index (LAI), defined as the one‐sided total green leaf area per unit ground surface area, is useful for characterizing variation in plant canopies. We estimated LAI with allometry for trees and tall shrubs (>0.5 and <1.5 m) across 26 sites with varying tree stem density (0.05–3.3 stems/m2) and canopy cover (4.6%–76.9%) in a uniformly‐aged mature Siberian larch forest that regenerated following a fire ∼75 years ago. We investigated relationships between tree density, tree LAI, and tall shrub LAI, and between LAI and satellite observations of Normalized Difference and Enhanced Vegetation Indices (NDVI and EVI). Across the density gradient, tree LAI increases with increasing tree density, while tall shrub LAI decreases, exhibiting no patterns in combined tree‐shrub LAI. We also found significant positive relationships between tall shrub LAI and NDVI/EVI from PlanetScope and Landsat imagery. These findings suggest that tall shrubs compensate for lower tree LAI in tree canopy gaps, forming a canopy with contiguous combined tree‐shrub LAI across the density gradient. Our findings suggest that NDVI and EVI are more sensitive to variation in tall shrub canopies than variation in tree canopies or combined tree‐shrub canopies in these ecosystems. The results improve our understanding of the relationships between forest density and tree and shrub leaf area and have implications for interpreting spatial variability in LAI, NDVI, and EVI in Siberian boreal forests.

极端干旱区多枝柽柳叶片功能性状及其与土壤理化因子的关系

PDF HTML阅读 XML下载 导出引用 引用提醒 极端干旱区多枝柽柳叶片功能性状及其与土壤理化因子的关系 DOI: 10.5846/stxb202204070904 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 新疆维吾尔自治区自然科学基金(2020D01C053);国家自然科学基金(32001145);新疆维吾尔自治区教育厅"天池博士计划"(TCBS202054) Leaf functional traits of Tamarix ramosissima in extremely arid region and their relationship with soil physicochemical factors Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:叶片是植物获取资源的重要器官,研究其功能性状与环境因子的关系,有助于更好地了解植物对环境要素变化的生态适应性。以塔里木盆地北缘不同生境下(绿洲、过渡带、荒漠)典型荒漠植物多枝柽柳(Tamarix ramosissima)为研究对象,分析其叶片结构和生理性状在不同生境间的差异,建立叶片性状与土壤理化因子的相关关系,解析荒漠植物的生态适应性并揭示影响荒漠植物叶片功能性状的关键环境因子。结果表明:(1)多枝柽柳叶片功能性状具有不同程度的变异,其中叶片面积变异幅度最大(40%),比叶面积、可溶性蛋白含量等变异幅度最小(均为15%)。(2)多枝柽柳叶片厚度和叶片面积等结构性状以及叶片可溶性蛋白、脯氨酸、淀粉含量等生理性状在不同生境中均具有显著差异(P<0.05),其中可溶性蛋白、脯氨酸含量均在荒漠生境中达到最高。(3)多枝柽柳叶片部分功能性状之间存在显著的相关关系,其中叶片厚度、淀粉含量等与叶组织密度呈显著负相关关系(P<0.05),而叶片厚度与淀粉含量之间、可溶性糖含量与非结构性碳水化合物含量之间均呈极显著正相关关系(P<0.01)。(4)通过RDA排序分析发现,土壤速效磷含量、土壤含水量、pH、容重等土壤环境因子影响较大,对多枝柽柳叶片功能性状有较好的解释。研究表明多枝柽柳通过叶片功能性状变化以及性状之间协同-权衡的生态对策来适应极端干旱环境,土壤水分和速效磷含量是影响其叶片功能性状最关键的土壤环境因子,研究可为极端干旱区荒漠植被的科学管理、保护和恢复提供理论依据。 Abstract:Leaf is an important organ for plants to obtain resources. Studying the relationships between its functional traits and environmental factors helps to better understand the ecological adaptability of plants to environmental changes. In this study, with the aim of determining the ecological adaptations of desert plants and revealing the environmental factors that influencing the functional traits of them, we investigated a typical desert plant, Tamarix ramosissima, in different habitats (oasis, transition zone and desert) at the northern edge of the Tarim Basin, analyzed the differences in its leaf structure and physiological traits, and established the correlation between them with soil physicochemical factors. The results showed that: (1) the functional traits of Tamarix ramosissima leaves exhibited different degrees of variation, with the greatest variation in leaf area (40%) and the least variation in specific leaf area and soluble protein content (both 15%). (2) The structural traits including leaf thickness and leaf area, as well as physiological traits including leaf soluble protein, proline, and starch contents of Tamarix ramosissima were significantly different among the three habitats (P<0.05), with soluble protein and proline contents reaching the highest levels in desert habitats. (3) There were significant correlations between several functional traits of Tamarix ramosissima leaves. Leaf thickness and starch content were significantly negatively correlated with leaf tissue density (P<0.05), while the correlations between leaf thickness and starch content, soluble sugar content and non-structural carbohydrate content were significantly positive (P<0.01). (4) The RDA analysis revealed that soil environmental factors including soil available phosphorus content, soil water content, pH and bulk density had the greatest influence, and could explain the leaf functional trait variations of Tamarix ramosissima better. This study indicates that Tamarix ramosissima adapts to extreme arid environment by developing ecological responses that varying in leaf functional traits and forming synergistic trade-offs between them. Soil available phosphorus content and soil water content are the most critical soil environmental factors affecting leaf functional traits of Tamarix ramosissima. The findings of this study provide a theoretical basis for the scientific management, conservation, and restoration of desert vegetation in extreme arid region. 参考文献 相似文献 引证文献

Similar soil drying-induced stomatal closure in soybean genotypes varying in abscisic acid accumulation and stomatal sensitivity to abscisic acid.

Different soybean cultivars (Williams 82 , Union , Jindou 21 , Long Huang 1 , Long Huang 2 ) were exposed to drying soil, to investigate whether endogenous abscisic acid (ABA) concentrations and leaf water relations regulated stomatal behaviour. We measured ABA concentrations in xylem and tissue of the first and second trifoliate leaves respectively; stomatal conductance (gs ) and leaf water potential (Ψleaf ) in both leaves; and water content in soil. Cultivar variation in leaf area and g s caused different rates of soil drying, but g s and Ψ leaf declined similarly with soil drying in all cultivars. Variation in leaf xylem ABA concentration better explained stomatal responses than foliar ABA concentration in some cultivars, and was highly correlated with stomatal conductance. Xylem ABA concentration in well-watered soil was highest in Union , and in drying soil was lowest in Jindou 21 and Long Huang 2 , although the latter had the highest foliar ABA concentrations. Jindou 21 accumulated lower xylem ABA concentrations than other cultivars as soil moisture or Ψ leaf decreased, but its stomatal sensitivity to xylem ABA was greater. Because cultivars varied in both ABA accumulation and stomatal sensitivity to ABA, but had similar stomatal sensitivity to Ψ leaf , leaf water relations seem more important in regulating stomatal closure of soybean.

Growth and production of crisp lettuce (Lactuca sativa L.) using different doses of nitrogen and magnesium

Lettuce is part of the group of leafy vegetables that sees high consumption worldwide. However, population increases have forced excessive increases in fertilization, raising N levels both in the water and the soil and leading to serious environmental problems. As a result, appropriate fertilization management must be carried out; therefore, this study aimed to determine the effect of nitrogen and magnesium on the growth and yield of crisp lettuce. A randomized complete block design was carried out with 10 treatments: a control plus nine treatments with a central compound and different combinations of nitrogen and magnesium doses. The variables leaf area ratio, SPAD chlorophyll index and relative growth rate decreased throughout the crop cycle. The application of 150 kg ha-1 of N + 18 kg ha-1 of Mg generated the highest production values and net assimilation rate. The response surface graph yielded a model with a maximum yield of 21 t ha-1 using fertilization with 93.8 kg ha-1 of nitrogen and 12.4 kg ha-1 of magnesium. The lower doses of both nitrogenous and magnesium fertilization showed the highest values of agronomic efficiency and partial productivity.

Evolution of turbulent flow characteristics in a hedgerow vineyard during the growing season

The characteristics of turbulent flow at the land-atmosphere interface and within plant canopies are strongly modified by the interactions with vegetation elements. However, only few experimental studies were conducted so far on the effect of changing leaf area on within-canopy turbulence statistics. This aspect is important for deciduous forests and perennial woody crops (orchards and vineyards), where the variation of leaf area is recurrent and substantial during the growing season. Increasing the understanding on canopy turbulence is fundamental to improve the parameterization of multi-layer models to predict vegetation-atmosphere exchanges. In this context, we conducted an experimental campaign in a hedgerow vineyard in North-East Italy carrying out measurements with a vertical array of 3D sonic anemometers, together with canopy structure characterization, in order to analyze the evolution of turbulent flow characteristics from a leafless canopy to full development. Additionally, the effects of wind direction with respect to rows and of atmospheric stability were analyzed. We found that the aerodynamic properties of the vineyard were not only influenced by canopy height and total leaf area, but also by the vertical distribution of leaf density, with the thickness of the mid-upper layer playing a major role in determining the canopy roughness and the mean level of momentum absorption. The characteristics of within-canopy turbulent flow became more similar to a well-defined mixing-layer type flow as foliage developed, but only for diagonal and across-row wind. In contrast, with wind parallel to rows the effect of increasing leaf density was lower and the vineyard was more similar to an open canopy. The influence of atmospheric stability was less important compared to wind direction or leaf density, except for the free convection class. Nevertheless, a variation of canopy aerodynamic parameters with stability was observed and this should be taken into account in atmospheric models.

The Effect of POC Consetration and Planting Media on the Growth and Production of Pakcoy Aawi Plants (Brassica Rapa L).

This research was conducted in the village of jiken Tulangan sidoarjo. Aims to determine the effect of POC dosage and growing media on the growth and yield of pakcoy mustard. As wel as to determine the correct dosage of POC and planting media for the growth of pakcoy and mustard in order to obtain the highest yield. The experiment was arraged in a factorial design used was a rendomized block design (RBN) with the first factors P1, P2, P3 and the second factor M1, M2 which ware repeated 4 time, in order to obtain 24 experimental units. The variabels observed ware plant height, number of leaves, dtem diameters, leaf area, wet weight, and antioxidants. Were analysed using ANOVA 5% to determine the differences between treatments. The results showed that admistration of POC dosage and the planting medium had in teraction on the variable leaf area at the age of 40 days after which the highest average was 26,63 treatment of soil and compost growing media with POC 15ml/liter (M1P1) compared to other treatments and the lowest average was 23,50 treatments of soil planting media, compost, cow manure with a POC dosage of 20ml/liter (M2P2). And there was no interaction on the observation variables of plant height, number of leaves, stem diameter, and wet weight. A good antioxidant test occurs in the treatment of soil and compost growing media with a POC dosage of 25ml/liter (M1P3) with value of 124,226 which is classified as moderate antioxidant because the IC50 value is between 100-150 μg/ml.