Leaf Phosphorus Content Research Articles

Is local trait variation related to total range size of tropical trees?

The reasons why the range size of closely related species often varies significantly have intrigued scientists for many years. Among other hypotheses, species with high trait variation were suggested to occupy more diverse environments, have more continuity in their distributions, and consequently have larger range sizes. Here, using 34 tree species of lowlands tropical rainforest in southern Costa Rica, we explored whether inherent trait variability expressed at the local scale in functional traits is related to the species’ total geographical range size. We formed 17 congeneric pairs of one narrow endemic and one widespread species, sampled 335 individuals and measured eight functional traits: leaf area, leaf thickness, leaf dry matter content, specific leaf area, leaf nitrogen content, leaf phosphorus content, leaf nitrogen to phosphorus ratio, and wood specific gravity. We tested whether there are significant differences in the locally expressed variation of individual traits or in multidimensional trait variance between the species in congeneric pairs and whether species’ range size could hence be predicted from local trait variability. However, we could not find such differences between widely distributed and narrow range species. We discuss the possible reasons for these findings including the fact that higher trait variability of widespread species may result from successive local adaptations during range expansion and may hence often be an effect rather than the cause of larger ranges.

Abiotic and biotic determinants of coarse woody productivity in temperate mixed forests

Forests play an important role in regulating the global carbon cycle. Yet, how abiotic (i.e. soil nutrients) and biotic (i.e. tree diversity, stand structure and initial biomass) factors simultaneously contribute to aboveground biomass (coarse woody) productivity, and how the relative importance of these factors changes over succession remain poorly studied. Coarse woody productivity (CWP) was estimated as the annual aboveground biomass gain of stems using 10-year census data in old growth and secondary forests (25-ha and 4.8-ha, respectively) in northeast China. Boosted regression tree (BRT) model was used to evaluate the relative contribution of multiple metrics of tree diversity (taxonomic, functional and phylogenetic diversity and trait composition as well as stand structure attributes), stand initial biomass and soil nutrients on productivity in the studied forests. Our results showed that community-weighted mean of leaf phosphorus content, initial stand biomass and soil nutrients were the three most important individual predictors for CWP in secondary forest. Instead, initial stand biomass, rather than diversity and functional trait composition (vegetation quality) was the most parsimonious predictor of CWP in old growth forest. By comparing the results from secondary and old growth forest, the summed relative contribution of trait composition and soil nutrients on productivity decreased as those of diversity indices and initial biomass increased, suggesting the stronger effect of diversity and vegetation quantity over time. Vegetation quantity, rather than diversity and soil nutrients, is the main driver of forest productivity in temperate mixed forest. Our results imply that diversity effect for productivity in natural forests may not be so important as often suggested, at least not during the later stage of forest succession. This finding suggests that as a change of the importance of different divers of productivity, the environmentally driven filtering decreases and competitively driven niche differentiation increases with forest succession.

Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.

To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FRic, FEve, FDiv, FDis, Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.

Effects of the invasive herb Ageratina adenophora on understory plant communities and tree seedling growth in Pinus yunnanensis forests in Yunnan, China

ABSTRACTUnderstanding the influence of invasive species on understory communities is necessary to maintain ecosystem functions. Here, we describe the effects of different abundances of the invasive species Ageratina adenophora on the composition and structure of understory communities and on Pinus yunnanensis seedling growth under pine stands in mid-Yunnan, China. Our data show that the different abundances of A. adenophora altered species and functional diversity by changing the species composition and abundance in the understory community because of its higher specific leaf area, leaf nitrogen concentration (LNC), and leaf phosphorus concentration compared with native species. Meanwhile, the presence of A. adenophora led to changes in the patterns of species co-occurrence, with a shift from random to segregated patterns as the invasion intensity increased. Furthermore, the order of species loss under invasion was nonrandom. The LNC could be an indicative functional trait predicting the order of species loss, suggesting that species with a lower LNC were lost first with increasing invasion intensity. In addition, a high abundance of the invader A. adenophora suppressed the growth of the seedlings of native canopy trees. Our results indicate that the effect of the invasive herb A. adenophora on the understory community is associated with the nonrandom loss of species with different LNCs and that invasion also suppresses the growth of native canopy dominants.

Foliar nutrient resorption responses of three life-form plants to water and nitrogen additions in a temperate desert

How nitrogen deposition and increasing precipitation would affect leaf nutrient concentration and internal nutrient cycling of desert plants is still unclear. The aim of our study was to test the responses of leaf nutrient resorption to increasing precipitation and N enrichment in a temperate desert. Green and senesced leaf nitrogen and phosphorus concentrations, and nitrogen (NRE) and phosphorus (PRE) resorption efficiency of three life-form plants (5 spring annuals, 2 summer annuals and 2 shrubs) were investigated. Both NRE and PRE showed remarkable variations among plant life-forms, being lowest in shrubs and highest in spring annuals, suggesting that plants may have different nutrient requiring strategies. Nitrogen addition promoted green and senesced leaf nitrogen concentrations in summer annuals and shrubs, while having no impacts on leaf phosphorus concentration, NRE and PRE. Water addition had no impacts on leaf nutrient concentration and resorption efficiency; combined nitrogen and water addition had no interactive effects. Our results suggest that spring annuals and shrubs exhibit conservative nutrient adaptation through increasing nutrient uptake but not changing nutrient internal cycle to increasing nitrogen and water.

Trait-abundance relation in response to nutrient addition in a Tibetan alpine meadow: The importance of species trade-off in resource conservation and acquisition.

In competition‐dominated communities, traits promoting resource conservation and competitive ability are expected to have an important influence on species relative abundance (SRA). Yet, few studies have tested the trait‐abundance relations in the line of species trade‐off in resource conservation versus acquisition, indicating by multiple traits coordination. We measured SRA and key functional traits involving leaf economic spectrum (SLA, specific leaf area; LDMC, leaf dry matter content; LCC, leaf carbon concentration; LNC, leaf nitrogen concentration; LPC, leaf phosphorus concentration; Hs, mature height) for ten common species in all plots subjected to addition of nitrogen fertilizer (N), phosphorus fertilizer (P), or both of them (NP) in a Tibetan alpine meadow. We test whether SRA is positively related with traits promoting plant resource conservation, while negatively correlated with traits promoting plant growth and resource acquisition. We found that species were primarily differentiated along a trade‐off axis involving traits promoting nutrient acquisition and fast growth (e.g., LPC and SLA) versus traits promoting resource conservation and competition ability (e.g., large LDMC). We further found that SRA was positively correlated with plant height, LDMC, and LCC, but negatively associated with SLA and leaf nutrient concentration irrespective of fertilization. A stronger positive height‐SRA was found in NP‐fertilized plots than in other plots, while negative correlations between SRA and SLA and LPC were found in N or P fertilized plots. The results indicate that species trade‐off in nutrient acquisition and resource conservation was a key driver of SRA in competition‐dominated communities following fertilization, with the linkage between SRA and traits depending on plant competition for specific soil nutrient and/or light availability. The results highlight the importance of competitive exclusion in plant community assembly following fertilization and suggest that abundant species in local communities become dominated at expense of growth while infrequent species hold an advantage in fast growth and dispersals to neighbor meta‐communities.

Inter-Annual and Seasonal Variation of ANPP and Leaf Nutrient Concentration in Cold-Temperate Wetlands of Tierra del Fuego

We investigated the inter-annual and seasonal variation of the aboveground net primary productivity (ANPP), and leaf nitrogen and phosphorus concentrations across two different types of wet meadows (spring-fed and riparian) in Tierra del Fuego Island, Southern Patagonia. In addition, we estimated grazing effects on ANPP, the nature of nutrient limitation, and the resorption efficiencies for both nutrients. ANPP showed a high inter-annual variation (CV = 49–57%), typical seasonal dynamics with a summer peak, and higher annual means at the spring-fed meadows (532 g∙m−2∙yr.−1) compared to the riparian meadows (310 g∙m−2∙yr.−1) with a higher contribution of graminoids (50–65%). Sheep grazing reduced a 66% the annual mean of ANPP (108 g∙m−2∙yr.−1) in riparian meadows. Leaf nitrogen concentrations were similar to reported values for graminoids from temperate and cold regions (1.5–2.5%), while leaf phosphorus concentrations were markedly higher (0.2–0.3%), indicating a nitrogen limitation. Resorption efficiency was 54.2% for nitrogen and 48.2% for phosphorus, exhibiting incomplete resorption proficiency for both nutrients. Our results represent valuable information to design sustainable management strategies for wetlands according to their spatial and temporal variation, and to define a baseline of vegetation functioning to assess the impact of climate change in high-latitude southern ecosystems.

Demographic drivers of functional composition dynamics.

Mechanisms of community assembly and ecosystem function are often analyzed using community-weighted mean trait values (CWMs). We present a novel conceptual framework to quantify the contribution of demographic processes (i.e., growth, recruitment, and mortality) to temporal changes in CWMs. We used this framework to analyze mechanisms of secondary succession in wet tropical forests in Mexico. Seed size increased over time, reflecting a trade-off between colonization by small seeds early in succession, to establishment by large seeds later in succession. Specific leaf area (SLA) and leaf phosphorus content decreased over time, reflecting a trade-off between fast growth early in succession vs. high survival late in succession. On average, CWM shifts were driven mainly (70%) by growth of surviving trees that comprise the bulk of standing biomass, then mortality (25%), and weakly by recruitment (5%). Trait shifts of growing and recruiting trees mirrored the CWM trait shifts, and traits of dying trees did not change during succession, indicating that these traits are important for recruitment and growth, but not for mortality, during the first 30yr of succession. Identifying the demographic drivers of functional composition change links population dynamics to community change, and enhances insights into mechanisms of succession.

Response of Korean pine's functional traits to geography and climate.

This study analyzed the characteristics of Korean pine (Pinus koraiensis) functional trait responses to geographic and climatic factors in the eastern region of Northeast China (41°–48°N) and the linear relationships among Korean pine functional traits, to explore this species’ adaptability and ecological regulation strategies under different environmental conditions. Korean pine samples were collected from eight sites located at different latitudes, and the following factors were determined for each site: geographic factors—latitude, longitude, and altitude; temperature factors—mean annual temperature (MAT), growth season mean temperature (GST), and mean temperature of the coldest month (MTCM); and moisture factors—annual precipitation (AP), growth season precipitation (GSP), and potential evapotranspiration (PET). The Korean pine functional traits examined were specific leaf area (SLA), leaf thickness (LT), leaf dry matter content (LDMC), specific root length (SRL), leaf nitrogen content (LNC), leaf phosphorus content (LPC), root nitrogen content (RNC), and root phosphorus content (RPC). The results showed that Korean pine functional traits were significantly correlated to latitude, altitude, GST, MTCM, AP, GSP, and PET. Among the Korean pine functional traits, SLA showed significant linear relationships with LT, LDMC, LNC, LPC, and RPC, and LT showed significant linear relationships with LDMC, SRL, LNC, LPC, RNC, and RPC; the linear relationships between LNC, LPC, RNC, and RPC were also significant. In conclusion, Korean pine functional trait responses to latitude resulted in its adaptation to geographic and climatic factors. The main limiting factors were precipitation and evapotranspiration, followed by altitude, latitude, GST, and MTCM. The impacts of longitude and MAT were not obvious. Changes in precipitation and temperature were most responsible for the close correlation among Korean pine functional traits, reflecting its adaption to habitat variation.

When the same is not the same: phenotypic variation reveals different plant ecological strategies within species occurring in distinct Neotropical savanna habitats

Variations in abiotic characteristics such as soil water availability and fertility impose different selective pressures on plant populations. This may produce intraspecific variability in functional traits, even at a fine spatial scale. We investigated whether functional traits related to water-use efficiency, resource-retention strategy, soil nutrient acquisition, and fire tolerance differ in species that occur in two different habitats of Brazilian Cerrado: rocky savannas and savanna woodlands. Rocky savannas occur over sandstone, quartzite outcrops and have shallow nutrient-poor and low-moisture rocky soils, while savanna woodlands occur over well-drained and deep soils with frequent fire regimes. We measured nine functional traits of 40 tree species that occur in both habitats. Rocky savanna individuals exhibited a greater water-use efficiency strategy. The resource-retention strategy in rocky savanna individuals was corroborated by lower adult maximum height. However, despite the lower nutrient availability in rocky savanna soils, we only detected lower leaf phosphorus content in individuals from this habitat. Furthermore, individuals from both habitats had equally thick bark, suggesting that the fire-defense strategy is related to a stable, rather than plastic trait. Overall, our results highlight the central role of contrasting soil water availability patterns in driving phenotypic plasticity within species. We conclude that savanna species are responding to water and nutrient availabilities, via plasticity in traits related to the resource-retention strategy, and preparing for future fires, via uniformly thick bark. Wide plant distribution in contrasting habitats is possible for species that can shift ecological strategies to survive in nutrient- and water-limited habitats such as rocky savannas.

Stress from cold and drought as drivers of functional trait spectra in North American angiosperm tree assemblages.

Understanding how environmental change alters the composition of plant assemblages, and how this in turn affects ecosystem functioning is a major challenge in the face of global climate change. Assuming that values of plant traits express species adaptations to the environment, the trait‐based approach is a promising way to achieve this goal. Nevertheless, how functional traits are related to species’ environmental tolerances and how trait spectra respond to broad‐scale environmental gradients remains largely unexplored. Here, we identify the main trait spectra for US angiosperm trees by testing hypotheses for the relationships between functional traits and species’ environmental tolerances to environmental stresses, as well as quantifying the environmental drivers of assemblage means and variances of these traits. We analyzed >74,000 community assemblages from the US Forest Inventory and Analysis using 12 functional traits, five traits expressing species’ environmental tolerances and 10 environmental variables. Results indicated that leaf traits, dispersal traits, and traits related to stem hydraulics were related to cold or drought tolerance, and their assemblage means were best explained by minimum temperatures. Assemblage means of traits related to shade tolerance (tree growth rate, leaf phosphorus content, and bark thickness) were best explained by aridity index. Surprisingly, aridity index, rather than minimum temperature, was the best predictors of assemblage variances of most traits, although these relationships were variable and weak overall. We conclude that temperature is likely to be the most important driver of functional community structure of North American angiosperm trees by selecting for optimum strategies along the cold and drought stress trade‐off. In turn, water availability primarily affects traits related to shade tolerance through its effect on forest canopy structure and vegetation openness.

English

The objective of this work was to evaluate the effect of different forms of reimplantation of pasture with and without phosphatation aiming to contribute to the increase of soybean yield. The experiment was conducted at the Experimental Farm of Universidade do Oeste Paulista (Unoeste), located in the municipality of Presidente Bernardes - SP. The design was done with split plot scheme, containing four replicates. The plots were constituted with 4 kg ha-1 of Urochloa brizantha (Marandu grass), BNS + Seeding in haul, BNS + Seeding in line consortium with soybean as subplots (with and without phosphatation). The following were analyzed: number of tillers and dry mass yield (PMS); analysis of plant tissue from pasture; foliar diagnosis analysis; and components of production and production of soy. Analyzed variables were submitted to analysis of variance (p <0.05) and means were compared by the Tukey test (p <0.05). In this context, it can be concluded that a higher quality production with a reimplantation of pasture intercropped with a soybean crop yielding an increase of 276 kg ha-1 compared to the treatment that did not have pasture reimplantation (BNS). Phosphate increased soil phosphorus content in the production of soybean dry matter and no leaf phosphorus content and higher soybean yield. Key words: Natural seed bank, no-tillage, Urochloa brizantha.

Variations of water use efficiency and its relationship with leaf nutrients of different altitudes of Wuyi Mountains, China

We determined the water use efficiency and nitrogen and phosphorus concentrations of plants at different altitudes (600, 900, 1300, 1500, 1800, 2000, 2100 m) in Wuyi Mountains to understand the relationship of water use efficiency with foliar nutrients. The results showed that plant water use efficiency increased with altitude, and the leaf δ18O of tree showed no significant variance with altitude. On the whole, leaf nitrogen concentration showed no obvious trend, while leaf phosphorus concentration at high altitude was significantly higher than that at low altitude. No significant relationship between water use efficiency and foliar nitrogen concentration was found in this study, but water use efficiency had a positive correlation with foliar phosphorus concentration. In conclusion, the change of water use efficiency was mainly caused by the difference in photosynthetic rate. The effect of water status on plant water use efficiency was not significant. The variances of leaf phosphorus concentrations along the altitudinal gradient may affect photosynthetic rate and in turn the water use efficiency of plant in this area.

Influence of nutritional status of phosphorus on flowering in the olive (Olea europaea L.)

Two different field experiments were carried out during four years with one-year-old olive trees recently planted. In the first experiment, ‘Hojiblanca’, ‘Picual’ and ‘Arbequina’ received several foliar applications along each season of 0, 100 or 200ppm phosphorus. The second experiment was established with 24 olive cultivars to determine the effect of cultivars in the nutritional status of phosphorus and flowering. No phosphorus fertilizers were applied in this experiment. Foliar application of phosphorus to young olive trees during several seasons did not increase phosphorus concentration in leaves. This lack of response to phosphorus application could be because these trees have high levels of phosphorus in leaves. Consequently, no effect on vegetative growth or flowering was observed in response to phosphorus application. Differences in vigor, phosphorus level, and the time of first flowering were observed among cultivars, but no relationship was found between leaf phosphorus concentration and vigor or the time of first flowering. Results indicate that if the nutritional status of phosphorus in olive trees is above the sufficiency threshold phosphorus does not affect flowering. The time of first flowering seems to depend on the cultivar.

Geographical variation and the role of climate in leaf traits of a relict tree species across its distribution in China.

Intraspecific trait variation and trait-climate relationships are crucial for understanding a species' response to climate change. However, these phenomena have rarely been studied for tree species. Euptelea pleiospermum is a relict tree species with a wide distribution in China that offers a novel opportunity to examine such relationships. Here, we measured 13 leaf traits of E.pleiospermum in 20 sites across its natural distribution in China. We investigated the extent of trait variation at local and regional scales, and developed geographic and climate models to explain trait variation at the regional scale. We documented intraspecific trait variation among leaf traits of E.pleiospermum at local and regional scales. Five traits exhibited relatively high trait variation: leaf area, leaf density and three leaf economic traits (leaf dry matter content, specific leaf area [SLA] and leaf phosphorus concentration). Significant trait-geography correlations were mediated by local climate. Most leaf trait variation could be explained (from 24% to 64%) by geographic or climate variables, except leaf width, leaf thickness, leaf dry matter content and leaf length-width ratio. Latitude and temperature were the strongest predictors of trait variation throughout the distribution of E.pleiospermum in China, and temperature explained more leaf trait variation than precipitation. In particular, we showed that leaves had longer petiole lengths, higher SLA and lower densities in northern E.pleiospermum populations. We suggest that northern E.pleiospermum populations are adapting to higher latitudinal environments via high growth rate (higher SLA) and low construction investment strategies (lower leaf densities), benefitting northern migration. Overall, we demonstrate that intraspecific trait variation reflects E.pleiospermum response to the local environment. We call for consideration of intraspecific trait variation to examine specific climate response questions. In addition, provenance experiments using widely distributed species are needed to separate trait variation resulting from genetic differentiation and plastic responses to environmental change.

Characterization of Phosphorus Forms in Organic Composts and Their Effects on Leaf Phosphorus Content of Castanea mollissima in Chinese Chestnut Producing Area

Characterization of the forms of phosphorus (P) in four organic composts including compost of hulls and leaves of Castanea mollissima, edible fungi residues, corn stalks and chicken manure (BYZ), compost of edible fungi residues and chicken manure(ZF), composts of hulls and leaves of C. mollissima, edible fungi residues and chicken manure (BZ1 and BZ2) in Chinese chestnut producing area was conducted by sequential P fractionation developed by Dou et al. Field trial was conducted to study the effects of compost application on leaf phosphorus content of Castanea mollissima. The results showed that total phosphorus content(TP) of organic composts ranked as follows:BZ1(10.61 g·kg-1) > ZF(9.03 g·kg-1) > BYZ(8.56 g·kg-1) > BZ2(7.68 g·kg-1), and the inorganic phosphorus(Pi) accounted for 62.88%-73.62% of the total phosphorus in the organic composts. The content and proportion of HCl-P in the total fractionated phosphorus(Prt) was the highest among P forms in ZF, while that of H2O-P was the highest in BYZ, BZ1 and BZ2. The content of NaOH-P was very low in all the composts. Active H2O-Por NaHCO3-P had the highest inorganic phosphorus proportion(89.17%-96.00%) of all the P forms. The major Piforms in BZ2 were H2O- and HCl-extractable P fractions, while H2O-Pi, HCl-Pi and NaHCO3-Pi were major Pi forms in BYZ, BZ1 and ZF. Residual-P was the predominant organic phosphorus form, and BZ2 showed the highest Residual-P proportion of the total fractionated phosphorus(Prt) among all the composts. Leaf phosphorus contents per unit area of Castanea mollissima by field trial on the added phosphorus-equivalent basis were expressed as:BZ2>BZ1>BYZ>ZF>CK. Increment of leaf phosphorus content per unit area in Julyand per month on average showed positive relationship with the content and proportion of H2O-Pi in the total fractionated phosphorus of composts, which presumably played a key role in leaf phosphorus absorption of C. mollissima measured in the year of deep concentrated fertilization. The results suggested that composts of hulls and leaves of C. mollissima, edible fungi residues and chicken manure (BZ2) was a good choice in given area for aerobic composting raw material system in which organic wastes from Chinese chestnut industry accounted for 80% (hulls and leaves of Castanea mollissima and edible fungi residues accounted for 60% and 20% respectively), which had a high proportion of H2O-Pi and organic Residual-P pool and led to the highest leaf phosphorus content of C. mollissima.

Interactive Short-term Effects of Waterlogging and Salinity Stress on Growth and Carbohydrate, Lipid Peroxidation, and Nutrients in Two Perennial Ryegrass Cultivars

Waterlogging can occur in salt-affected turfgrass sites. The objective of this study was to characterize growth and carbohydrate, lipid peroxidation, and nutrient levels in the leaves and roots of two perennial ryegrass (Lolium perenne) cultivars (Catalina and Inspire) to short-term simultaneous waterlogging and salinity stress. Previous research showed that ‘Catalina’ was relatively more tolerant to salinity but less tolerant to submergence than ‘Inspire’. Both cultivars were subjected to 3 and 7 days of waterlogging (W), salinity [S (300 mm NaCl)], and a combination of the two stresses (WS). Across the two cultivars, W alone had little effect on the plants, while both S and WS alone significantly decreased plant height (HT), leaf fresh weight (LFW), leaf dry weight (LDW), root fresh weight (RFW), root dry weight (RDW), leaf nitrogen (LN) and carbon (LC), and leaf and root K+ (RK+), and increased leaf water-soluble carbohydrate (LWSC) and root water-soluble carbohydrate (RWSC), malondialdehyde (MDA), and Na+ content, compared with the control. A decline in chlorophyll content (Chl) was found only at 7 days of WS. Leaf phosphorus (LP) content either decreased or remained unchanged but root phosphorus content increased under S and WS. Reductions in LFW and LDW were found at 3 days of S and WS, whereas RFW and RDW were unaffected until 7 days of S or WS. Both cultivars responded similarly to W, S, and WS with a few exceptions on RDW, LWSC, leaf MDA (LMDA), and root MDA (RMDA). Although WS caused declines in Chl and resulted in higher leaf Na+ (LNa+) and root Na+ (RNa+) than S at 7 days of treatment, S and WS had similar effects on growth, carbohydrate, MDA, N, C, and phosphorus, and K+ content across the two cultivars. The results suggested that S alone largely accounted for the negative effects of WS on plant growth and physiology including alteration of carbohydrate and nutrient content as well as induction of lipid peroxidation.

Seasonal variation of plant-parasitic nematodes and relationship with nutritional and growth properties of sugarcane plantations

The damage caused by Meloidogyne and Pratylenchus nematodes is included among the factors that limit growth and sustainability of sugarcane production. The objective of this study was to assess the seasonal changes and relationships between plant-parasitic nematode communities and plant variables (leaf chemical analysis and growth parameters) in sugarcane plantations in Pernambuco State, Brazil. Samples were collected at six, nine, and 12 months after planting in two sugarcane fields (plant cane and ratoon cane). Meloidogyne and Pratylenchus populations were extracted from sugarcane roots, counted and identified. Vegetative parameters that determine sugarcane growth pattern included stalk height, stalk diameter, and number of stalks and tillers. Leaf tissue was analyzed for potassium, phosphorus, calcium and magnesium contents. Meloidogyne and Pratylenchus abundance, plant nutrients and growth parameters in sugarcane plantations responded differently to environmental variation (i.e., temporal and sugarcane growth stage). Pratylenchus abundance decreased with the increase of leaf phosphorus content. Contrariwise, increases in potassium concentration resulted in high abundance of Meloidogyne. A positive association between the abundance of nematodes and sugarcane growth parameters suggest that the varieties planted in both study areas may present tolerance to Meloidogyne and Pratylenchus.

长白山针阔混交林不同演替阶段群落系统发育和功能性状结构

PDF HTML阅读 XML下载 导出引用 引用提醒 长白山针阔混交林不同演替阶段群落系统发育和功能性状结构 DOI: 10.5846/stxb201609141860 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划重点专项项目（2017YFC0504104）；国家自然科学基金项目（31670643） Phylogenetic development and functional structures during successional stages of conifer and broad-leaved mixed forest communities in Changbai Mountains, China 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:群落构建一直是生态学研究的热点，基于系统发育和功能性状量化生境过滤、竞争排斥以及随机过程在群落构建中的作用，能够深入理解群落构建机制。本研究以长白山针阔混交林不同演替阶段的3个5.2 hm2样地（次生杨桦林、次生针阔混交林、原始椴树红松林）为平台，基于被子植物分类系统Ⅲ（Angiosperm Classification System，APGⅢ）构建的系统发育树和7个关键功能性状（叶面积、比叶面积、叶片厚度、叶片氮含量、叶片磷含量、氮磷比、最大树高），结合环境数据，分析不同演替阶段群落系统发育和功能性状结构。研究表明：（1）各演替阶段7个植物功能性状都表现出显著的系统发育信号，表明植物功能性状受系统发育历史影响；（2）系统发育和功能性状结构在不同演替阶段和不同径级均为非随机状态。随着演替的推进群落系统发育和功能性状结构由聚集走向发散；随着径级的增加，系统发育和功能性状结构的聚集程度减小，表明随着演替阶段的进行和径级增大，竞争性排斥的作用逐渐明显；（3）各演替阶段系统发育和功能性状的周转都为非随机且不同因子对两者的解释力度存在差异。演替早期空间距离的解释力度小于环境距离，说明生境过滤在群落构建中的重要性，而在演替后期空间距离的解释力度大于环境距离，验证了扩散限制在群落构建中的重要性。 Abstract:Community assembly has long been an important issue in community ecology. By quantifying the influence of habitat filtering, competitive exclusion, and random community assembly on the phylogenetic and functional traits, ecologists would gain a deeper understanding of community construction. In this study, based on the datasets of three 5.2 hm2 permanent plots at different successional stages (i.e., a Populus davidiana-Betula platyphylla secondary forest, a secondary conifer and broad-leaved mixed forest, and a Primary Tilia amurensis-Pinus koraiensis forest), we established the phylogenetic trees according to the Angiosperm Classification System (APG Ⅲ) and seven functional traits (i.e., leaf area, specific leaf area, leaf thickness, leaf nitrogen content, leaf phosphorus content, nitrogen-phosphorus ratio, and maximum tree height). We correlated the phylogenetic trees with the environmental variables to examine the patterns of the phylogenetic and functional structures of the forest communities at different successional stages in Changbai Mountains of China. The results showed that:(1) at each successional stage, significant phylogenetic signals were found for all seven functional traits, indicating that the functional traits were influenced by the phylogenetic history. (2) Both the phylogenetic and functional structures were non-random at all successional stages and stem classes. The phylogenetic and functional structures changed from "clustered" to "overdispersed" during the succession of forest community. Meanwhile, the degree of phylogenetic and functional clustering decreased with an increase in diameter class, indicating a significant increase in competitive exclusion with the succession of forest community. (3) The phylogenetic and functional turnovers were non-random, and the explanatory ability of the factors to interpret the phylogenetic and functional turnover was different. In the early succession stage, the spatial distance explained more than the environmental distance, indicating the importance of habitat filtering in community assembly. However, in the late succession stage, the environmental distance explained more than the spatial distance, indicating the importance of dispersal limitation in community assembly. 参考文献 相似文献 引证文献

荒漠短命植物的养分含量与荧光特征初探

短命植物作为荒漠植被类群中的独特类型，植物叶片的荧光生理特征和养分含量之间具有极高的相关性。分别选取5种典型短命植物东方旱麦草(Eremopyrum orientale)、卷果涩芥(Malcolmia scorpioides)、狭果鹤虱(Lappula semiglabra)、四齿芥(Tetracme quadricormis)和硬萼软紫草(Arnebiade cumbens)自然生长比较一致的叶片作为研究材料，对叶片的叶绿素和养分含量以及荧光光响应进行了测定。结果表明，短命植物的叶绿素总量为1.24~2.67 mg∙g−1之间，叶绿素a、b含量之比达到5.80~12.86。叶片含N量在3.1%以上，含P量为0.22%~0.30%，含K量在3.15%~6.24%。短命植物的实际光化学量子产量ΦPSII平均在0.4以上，ETR受光强的抑制不明显，当光合有效辐射值超过1400 mol∙m−2∙s−1时，出现下降。 Ephemerals, including annual ephemerals and ephemeroid plants, are characterized by short- term growth rhythms and specific biological traits adapted to deserts or temperate broad-leaved deciduous forests. Their fluorescence physical characteristics had a significant correlation with their leaf contents. The chlorophyll content, nutrient content and response of the photosynthetic characteristics to the simulated light environmental changes of five desert ephemerals, Eremopyrum orientale, Malcolmia scorpioides, Lappula semiglabra, Tetracme quadricormis and Arnebiade cumbens, which distributed in Northwestern China, were investigated. The results showed that the chlorophyll content of ephemerals was between 1.24 and 2.67 mg∙g−1, with extremely high chla/ chlb values reaching 5.80 - 12.86. Ephemerals growing in barren desert had extremely high nutrient use efficiency, with leaf nitrogen content all above 3.1%, leaf phosphorus content between 0.22% and 0.30%, and leaf potassium content between 3.15% and 6.24%. The ΦPSII of ephemerals on average was above 0.4. The inhibition effect of high light intensity on electron transport rate (ETR) was not obvious, with the latter decreasing only when PAR was above 1400 mol∙m−2∙s−1.