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1.
Francisco Flores-de-Santiago John M. Kovacs Francisco Flores-Verdugo 《Wetlands Ecology and Management》2013,21(3):193-207
Mangrove photosynthetic activity and, consequently, physiological stress can be monitored indirectly using leaf chlorophyll-a (Chla) measurements. Recent studies have demonstrated the feasibility of mangrove leaf Chla content estimation from in situ hyperspectral vegetation indices (VI) but no such research has been conducted using data collected from contrasting seasons (i.e. dry and rainy). In this study, mangrove leaves were collected in a sub-tropical forest of the Mexican Pacific for Chla content determination and in situ hyperspectral measurements (450–1,000 nm). Specifically, we tested 35 VI to estimate Chla content based on a leaf sample of 360 collected from the same trees during both the dry and rainy seasons. The forest examined contained three species of mangrove (Rhizophora mangle, Avicennia germinans and Laguncularia racemosa) exhibiting various conditions of health (dwarf condition, tall and healthy). A principal component analysis, followed by linear regression analyses, were conducted in order to identify those VI that best predict mangrove leaf Chla content during the two seasons. The results indicate that VI derived from hyperspectral measurements collected during the dry season are better at estimating leaf Chla content than those collected during the rainy season. Among the 35 VI, the Vog1 (R740/R720) index was found to be the best predictor of mangrove leaf Chla content, resulting in R 2 values of 0.80 and 0.68 for the dry and rainy season respectively. These results would suggest that for identifying variation in mangrove forest stress (i.e. health) in sub-tropical regions, hyperspectral measurements should be carried out during the dry season. 相似文献
2.
We investigated the acclimation of seedlings of three tropical rain forest sub-canopy Garcinia species (G. xanthochymus, G. cowa, and G. bracteata) after transfer from 4.5 (LI) to 40 % (HI) sunlight and 12.5 (MI) sunlight to HI (LH1 and LH2 denoting transfer from LI to HI and MI to HI transfer, respectively). The changes of chlorophyll (Chl) fluorescence, net
photosynthetic rate (P
N), dark respiration rate (R
D), Chl content per unit area (Chlarea), leaf mass per unit area (LMA), and seedling mortality were monitored over two months after transfer. These parameters together
with leaf anatomy of transferred and control seedlings (kept in LI, MI, and HI) were also examined after two months. No seedlings
died during the two months. Fv/Fm, P
N, and Chlarea of the transferred seedlings decreased in the first 3 to 12 d. LH1 leaves showed larger reduction in Fv/Fm (>23 % vs. <16 %) and slower recovery of Fv/Fm than LH2 leaves. P
N started to recover after about one week of I transfer and approached higher values in all G. cowa seedlings and G. xanthochymus LH1 seedlings than those before the transfer. However, P
N of G. bracteata seedlings approached the values before transfer. The final P
N values in leaves of transferred G. xanthochymus and G. cowa seedlings approached that of leaves kept in HI, while the final P
N values of transferred leaves of G. bracteata were significantly lower than that of leaves grown under HI (p<0.05). R
D of G. xanthochymus LH1 seedlings and all G. cowa seedlings increased and approached the value of the seedlings in HI. The final Chlarea of both G. xanthochymus and G. cowa approached the values before transfer, but that of G. bracteata did not recover to the level before transfer. The final Chlarea of all transferred seedlings was not significantly different from that of seedlings in HI except that G. cowa LH1 seedlings had higher Chlarea than that in HI. LMA decreased within 2 d and then increased continuously until about 30 d and approached the value under
HI. Spongy/palisade mesophyll ratio decreased after transfer because of the increase in palisade thickness. Leaf thickness
did not change, so LMA increase of transferred seedlings was mainly due to the increase of leaf density. Thus the mature leaves
under LI and MI of G. xanthochymus and G. cowa are able to acclimate to HI by leaf physiological and anatomical adjustment, while G. bracteata had limited ability to acclimate to HI. 相似文献
3.
It is still unclear to what extent variations in foliar δ13C and nitrogen can be used to detect seasonal changes in canopy productivity. We hypothesize that in a wet and cloudy fir
forest, seasonally higher litterfall and lower leaf area index (LAI) are correlated with higher mass-based leaf nitrogen (N
mass) and net primary productivity (NPP), while foliar δ13C may change with specific leaf area (SLA), area-based leaf nitrogen (N
area), and/or starch concentration. In order to test our hypotheses, stand-level litterfall and the means of δ13C, N
mass, N
area, SLA, and starch concentration of canopy needles for a wet and cloudy Abies fabri forest in the Gongga Mountains were monthly measured during the growing season. Seasonal estimates of LAI were obtained from
our previous work. A conceptual model was used to predict seasonal NPP of the fir forest. Seasonal mean δ13C and N
mass and climatic variables were used as inputs. The δ13C across 1–7-year-old needles increased from May to September associated with decreasing SLA and increasing N
area. There were no significant differences in seasonal starch concentration. With increasing litterfall and decreasing LAI, seasonal
mean N
mass increased, while the δ13C varied little. The simulated NPP increased with increasing litterfall and related traits of N
mass and N
area. Our data generally supported the hypotheses. The results also suggest that in the forest with relatively moist and cloudy
environment, the largest fraction of annual carbon gain may occur in the early part of the growing season when higher litterfall
results in higher N
mass of canopy leaves. 相似文献
4.
X. B. Cheng J. Wu S. J. Han Y. M. Zhou X. X. Wang C. G. Wang J. Zhao Q. H. Hu 《Photosynthetica》2012,50(1):56-66
Leaf traits and physiology are species-specific and various with canopy position and leaf age. Leaf photosynthesis, morphology
and chemistry in the upper and lower canopy positions of Pinus koraiensis Sieb. et Zucc and Quercus mongolica Fisch. ex Turoz in broadleaved Korean pine forest were determined in September 2009. Canopy position did not significantly
affect light-saturated photosynthetic rate based on unit area (P
area) and unit dry mass (P
mass), apparent quantum yield (α), light compensation point (LCP), light saturation point (LSP); total nitrogen (Nm), phosphorus (Pm), carbon (Cm), and chlorophyll content (Chlm) per unit dry mass; leaf dry mass per unit area (LMA) and photosynthetic nitrogen-use efficiency (PNUE) for P. koraiensis current-year needles and Q. mongolica leaves. While in P. koraiensis one-year-old needles, P
area, P
mass, α and LCP in the upper canopy were lower than those in the lower canopy. The needles of P. koraiensis had higher Cm and LMA than leaves of Q. mongolica, but P
mass, Chlm and PNUE showed opposite trend. There were no differences in P
area, LSP, Nm, and Pm between the two species. Needle age significantly influenced photosynthetic parameters, chemistry and LMA of P. koraiensis needles except LCP, LSP and Cm. In contrast to LMA, P
area, P
mass, Nm, Pm, Chlm, and PNUE of one-year-old needles were significantly lower than those of current-year needles for P. koraiensis. The negative correlations between LMA and P
mass, Nm, Pm, Chlm, and positive correlations between P
mass and Nm, Pm, Chlm were found for P. koraiensis current-year needles and Q. mongolica leaves. Our results indicate that leaf nitrogen and phosphorus contents and nutrient absorption from soil are similar for
mature P. koraiensis and Q. mongolica growing in the same environment, while difference in carbon content between P. koraiensis and Q. mongolica may be attributed to inherent growth characteristics. 相似文献
5.
Noriyuki Osada 《Plant Ecology》2013,214(12):1493-1504
The theory of optimal nitrogen (N) distribution predicts that the carbon gain of plants will be maximised when leaves of higher irradiance have higher N content per area (N area). Most previous studies have examined optimal N distribution without explicitly considering the branching status of plants. I investigated light environment, N distribution and photosynthetic traits of individual leaves of an herbaceous species, Xanthium canadense. X. canadense was grown solitary under high (HN) and low nutrients (LN). Light availability, leaf mass per unit area and N area were measured for all leaves within plants. Daily photosynthesis of the plants of actual N distribution was compared with those of optimal and constant N distribution. Branch production was facilitated in HN but not in LN plants. N area was correlated more with leaf order than with leaf light environment. Although N was more limited and the light environment was less heterogeneous within crowns in LN than in HN plants, leaf N distribution was closer to optimal in the latter. These results suggest that leaf N distribution was not optimised in solitary plants of X. canadense. Because this species often regenerates in a dense stand, leaf N distribution might be selected to maximise carbon gain only in such a stand. Leaf N distribution might thus be constrained by the regeneration strategy of the species. 相似文献
6.
The theory of optimal leaf N distribution predicts that the C gain of plants is maximized when the N content per unit area (N area) scales with light availability, but most previous studies have demonstrated that the N distribution is not proportional to light availability. In tall trees, the leaves are often clustered on twigs (leaf cluster) and not evenly distributed within the crowns. Thus, we hypothesized that the suboptimal N distribution is partly caused by the limited capacity to translocate N between leaf clusters, and consequently, the relationship between light and N area differs for leaves in different clusters. We investigated the light availability and N content of all individual leaves within several leaf clusters on tall trees of a deciduous canopy species Fagus crenata in Japan. We observed that the within-cluster leaf N distribution patterns differed from the between-cluster patterns and the slopes of the relationships between light and N area were lower within clusters than between clusters. According to the detailed analysis of the N distribution within leaf clusters, N area was greater for current-year shoots with greater light availability or a larger total leaf area. The latter pattern was probably caused by the greater sink strength of the current-year shoots with a larger leaf area. These N distribution patterns suggest that leaf clusters are fairly independent with respect to their N use, and the productivity of real F. crenata crowns may be less than optimal. 相似文献
7.
Optimal photosynthetic use of light by tropical tree crowns achieved by adjustment of individual leaf angles and nitrogen content 总被引:2,自引:0,他引:2
Background and Aims
Theory for optimal allocation of foliar nitrogen (ONA) predicts that both nitrogen concentration and photosynthetic capacity will scale linearly with gradients of insolation within plant canopies. ONA is expected to allow plants to efficiently use both light and nitrogen. However, empirical data generally do not exhibit perfect ONA, and light-use optimization per se is little explored. The aim was to examine to what degree partitioning of nitrogen or light is optimized in the crowns of three tropical canopy tree species.Methods
Instantaneous photosynthetic photon flux density (PPFD) incident on the adaxial surface of individual leaves was measured along vertical PPFD gradients in tree canopies at a frequency of 0·5 Hz over 9–17 d, and summed to obtain the average daily integral of PPFD for each leaf to characterize its insolation regime. Also measured were leaf N per area (Narea), leaf mass per area (LMA), the cosine of leaf inclination and the parameters of the photosynthetic light response curve [photosynthetic capacity (Amax), dark respiration (Rd), apparent quantum yield (ϕ) and curvature (θ)]. The instantaneous PPFD measurements and light response curves were used to estimate leaf daily photosynthesis (Adaily) for each leaf.Key Results
Leaf Narea and Amax changed as a hyperbolic asymptotic function of the PPFD regime, not the linear relationship predicted by ONA. Despite this suboptimal nitrogen partitioning among leaves, Adaily did increase linearly with PPFD regime through co-ordinated adjustments in both leaf angle and physiology along canopy gradients in insolation, exhibiting a strong convergence among the three species.Conclusions
The results suggest that canopy tree leaves in this tropical forest optimize photosynthetic use of PPFD rather than N per se. Tropical tree canopies then can be considered simple ‘big-leaves’ in which all constituent ‘small leaves’ use PPFD with the same photosynthetic efficiency.Key words: Optimal resource allocation, nitrogen, photosynthetic capacity, leaf mass per area, tropical trees, radiation use efficiency, scaling, leaf angle, canopy architecture, big leaf model 相似文献8.
三种温带树种叶片呼吸的时间动态及其影响因子 总被引:1,自引:0,他引:1
为认知叶片呼吸(RL)的季节变化格局及其影响因子,以东北东部山区3个主要树种(红松Pinus koraiensis、樟子松P.sylvestris var.mongolica和白桦Betula platyphylla)为对象,采用红外气体分析法在2011年生长季(常绿树4月至10月;落叶树6月至9月)测定了自然条件下叶片气体交换及其相关生理特征的季节变化,探索了RL与空气温度(Tair)和相关叶片特征之间的关系.结果表明:红松和樟子松基于叶面积的RL(RL-area)表现为生长季初期和末期较大,而白桦RL-area则随生长季进程而逐渐减小.在生长季中,RL-area与叶片总光合之比的时间动态明显.红松、樟子松RL-area与Tair关系显著,而白桦RL-area与Tair关系不显著;但3种树种基于叶质量的RL(RL-mass)与Tair均呈显著的指数函数关系.叶片特征(包括可溶性糖、淀粉、氮、比叶面积等参数)也有明显的季节变化.影响RL的叶片特征参数因树种而异,其中可溶性糖浓度对3种树种的RL均有显著影响.可见,RL的季节变化格局受树木的生长节律、温度和叶片特征的联合控制. 相似文献
9.
Holly Croft Jing M. Chen Xiangzhong Luo Paul Bartlett Bin Chen Ralf M. Staebler 《Global Change Biology》2017,23(9):3513-3524
Improving the accuracy of estimates of forest carbon exchange is a central priority for understanding ecosystem response to increased atmospheric CO2 levels and improving carbon cycle modelling. However, the spatially continuous parameterization of photosynthetic capacity (Vcmax) at global scales and appropriate temporal intervals within terrestrial biosphere models (TBMs) remains unresolved. This research investigates the use of biochemical parameters for modelling leaf photosynthetic capacity within a deciduous forest. Particular attention is given to the impacts of seasonality on both leaf biophysical variables and physiological processes, and their interdependent relationships. Four deciduous tree species were sampled across three growing seasons (2013–2015), approximately every 10 days for leaf chlorophyll content (ChlLeaf) and canopy structure. Leaf nitrogen (NArea) was also measured during 2014. Leaf photosynthesis was measured during 2014–2015 using a Li‐6400 gas‐exchange system, with A‐Ci curves to model Vcmax. Results showed that seasonality and variations between species resulted in weak relationships between Vcmax normalized to 25°C () and NArea (R2 = 0.62, P < 0.001), whereas ChlLeaf demonstrated a much stronger correlation with (R2 = 0.78, P < 0.001). The relationship between ChlLeaf and NArea was also weak (R2 = 0.47, P < 0.001), possibly due to the dynamic partitioning of nitrogen, between and within photosynthetic and nonphotosynthetic fractions. The spatial and temporal variability of was mapped using Landsat TM/ETM satellite data across the forest site, using physical models to derive ChlLeaf. TBMs largely treat photosynthetic parameters as either fixed constants or varying according to leaf nitrogen content. This research challenges assumptions that simple NArea– relationships can reliably be used to constrain photosynthetic capacity in TBMs, even within the same plant functional type. It is suggested that ChlLeaf provides a more accurate, direct proxy for and is also more easily retrievable from satellite data. These results have important implications for carbon modelling within deciduous ecosystems. 相似文献
10.
Marcus V. Cianciaruso Igor A. Silva Lilian T. Manica João Paulo Souza 《Basic and Applied Ecology》2013,14(5):404-412
Plant species with a high leaf life span (LLS) commonly have a low specific leaf area (SLA), leaf nitrogen per unit mass (N), and phosphorous concentration (P), whereas species with low LLS have a high SLA, N and P. However, LLS tends to be longer in species growing in low-nutrient soils and, therefore, differences in LLS and other leaf traits may not be consistent with a plant classification according to leaf habit. Here we investigated whether leaf habit is consistent with leaf economic spectrum trade-offs in cerrado (a Neotropical savanna) woody species. We analyzed the SLA, N and P of 125 woody species with a distinct leaf habit (deciduous, semideciduous, brevideciduous or evergreen). We also gathered data on the LLS (33 species), maximum net photosynthesis per leaf area (Aarea, 56 species) and per leaf mass (Amass, 31 species), comprising the most extensive database analyzed so far for the cerrado. Differences among leaf habit groups were tested using generalized linear mixed models and ANOVA. We did not find differences in SLA and N among species with a distinct leaf habit, but deciduous species had a higher leaf P concentration than evergreens. Species did not differ in LLS and Amass, but Aarea varied among groups. Semideciduous species had higher Aarea values than deciduous and brevideciduous species, but all other groups had similar Aarea values. Because of the small difference in the LLS, SLA, leaf N, leaf P and maximum net photosynthesis, we argue that deciduous, brevideciduous, semideciduous and evergreen species may not constitute different functional groups in cerrado woody species. 相似文献
11.
E. Novriyanti M. Watanabe K. Makoto T. Takeda Y. Hashidoko T. Koike 《Photosynthetica》2012,50(2):273-281
The ecophysiological traits of acacia and eucalypt are important in assessing their suitability for afforestation. We measured the gas-exchange rate, the leaf dry mass per area (LMA) and the leaf nitrogen content of two acacia and four eucalypt species. Relative to the eucalypts, the acacias had lower leaf net photosynthetic rate (P N), lower photosynthetic nitrogen-use efficiency (PNUE), higher water-use efficiency (WUE), higher LMA and higher leaf nitrogen per unit area (N area). No clear differences were observed within or between genera in the maximum rate of carboxylation (V cmax) or the maximum rate of electron transport (J max), although these parameters tended to be higher in eucalypts. PNUE and LMA were negatively correlated. We conclude that acacias with higher LMA do not allocate nitrogen efficiently to photosynthetic system, explaining why their P N and PNUE were lower than in eucalypts. 相似文献
12.
A. G. Peterson J. T. Ball Y. Luo C. B. Field P. S. Curtis K. L. Griffin C. A. Gunderson R. J. Norby D. T. Tissue M. Forstreuter A. Rey C. S. Vogel & Cmeal Participants 《Plant, cell & environment》1999,22(9):1109-1119
Previous modelling exercises and conceptual arguments have predicted that a reduction in biochemical capacity for photosynthesis (Aarea) at elevated CO2 may be compensated by an increase in mesophyll tissue growth if the total amount of photosynthetic machinery per unit leaf area is maintained (i.e. morphological upregulation). The model prediction was based on modelling photosynthesis as a function of leaf N per unit leaf area (Narea), where Narea = Nmass×LMA. Here, Nmass is percentage leaf N and is used to estimate biochemical capacity and LMA is leaf mass per unit leaf area and is an index of leaf morphology. To assess the relative importance of changes in biochemical capacity versus leaf morphology we need to control for multiple correlations that are known, or that are likely to exist between CO2 concentration, Narea, Nmass, LMA and Aarea. Although this is impractical experimentally, we can control for these correlations statistically using systems of linear multiple-regression equations. We developed a linear model to partition the response of Aarea to elevated CO2 into components representing the independent and interactive effects of changes in indexes of biochemical capacity, leaf morphology and CO2 limitation of photosynthesis. The model was fitted to data from three pine and seven deciduous tree species grown in separate chamber-based field experiments. Photosynthetic enhancement at elevated CO2 due to morphological upregulation was negligible for most species. The response of Aarea in these species was dominated by the reduction in CO2 limitation occurring at higher CO2 concentration. However, some species displayed a significant reduction in potential photosynthesis at elevated CO2 due to an increase in LMA that was independent of any changes in Narea. This morphologically based inhibition of Aarea combined additively with a reduction in biochemical capacity to significantly offset the direct enhancement of Aarea caused by reduced CO2 limitation in two species. This offset was 100% for Acer rubrum, resulting in no net effect of elevated CO2 on Aarea for this species, and 44% for Betula pendula. This analysis shows that interactions between biochemical and morphological responses to elevated CO2 can have important effects on photosynthesis. 相似文献
13.
δ13C values of C3 plants are indicators of plant carbon–water relations that integrate plant responses to environmental conditions. However,
few studies have quantified spatial variation in plant δ13C at the landscape scale. We determined variation in leaf δ13C, leaf nitrogen per leaf area (Narea), and specific leaf area (SLA) in April and August 2005 for all individuals of three common woody species within a 308 × 12-m
belt transect spanning an upland–lowland topoedaphic gradient in a subtropical savanna in southern Texas. Clay content, available
soil moisture, and soil total N were all negatively correlated with elevation. The δ13C values of Prosopis glandulosa (deciduous N2-fixing tree legume), Condalia hookeri (evergreen shrub), and Zanthoxylum fagara (evergreen shrub) leaves increased 1–4‰ with decreasing elevation, with the δ13C value of P. glandulosa leaves being 1–3‰ higher than those of the two shrub species. Contrary to theory and results from previous studies, δ13C values were highest where soil water was most available, suggesting that some other variable was overriding or interacting
with water availability. Leaf Narea was positively correlated with leaf δ13C of all species (p < 0.01) and appeared to exert the strongest control over δ13C along this topoedaphic gradient. Since leaf Narea is positively related to photosynthetic capacity, plants with high leaf Narea are likely to have low p
I/p
a ratios and therefore higher δ13C values, assuming stomatal conductance is constant. Specific leaf area was not correlated significantly with leaf δ13C. Following a progressive growing season drought in July/August, leaf δ13C decreased. The lower δ13C in August may reflect the accumulation of 13C-depleted epicuticular leaf wax. We suggest control of leaf δ13C along this topoedaphic gradient is mediated by leaf Narea rather than by stomatal conductance limitations associated with water availability. 相似文献
14.
Jianxun Wang Mengying Zhong Ruixin Wu QuanMin Dong Kun Wang Xinqing Shao 《Ecological Research》2016,31(4):515-524
Above-ground biomass (AGB) is an important indicator of grassland ecosystem performance. Easily measured plant functional traits (PFTs) may provide useful predictors of the response of plants to grazing. Understanding the response of PFTs to grazing and the relationship between PFTs and AGB is very important for effectively predicting the response of ecosystems to grazing and rangeland management. A grazing experiment was conducted in Gangcha County, Qinghai Province, in the northeastern part of the Qinghai–Tibet Plateau in 2012 and 2013. We investigated the response of PFTs in three dominant species (Elymus nutans, Kobresia humilis, and Stipa purpurea) to grazing, using six stocking rates. Plant height (PH), plant weight, leaf area, and leaf dry biomass of these three dominant species had significantly negative relationships with stocking rate. Leaf thickness (LT) of these three species usually showed a unimodal response to grazing. Specific leaf area generally showed a quadratic relationship with grazing intensity. No consistent effects of grazing were observed on nitrogen content per unit mass (N mass) and nitrogen content per unit area (N area). PH, leaf area, and leaf dry mass (LDM) were positively associated with AGB, but LT, N mass, and N area had no statistically significant association with AGB. We thus conclude that PH, leaf area, and LDM best predict the effects of grazing on AGB. Finally, 2.87 sheep/ha is recommended as the optimal stocking rate in this region to maintain the health of this grassland ecosystem and to allow for sustainable development. 相似文献
15.
Optimal Leaf-to-Root Ratio and Leaf Nitrogen Content Determined by Light and Nitrogen Availabilities 总被引:1,自引:0,他引:1
Plants exhibit higher leaf-to-root ratios (L/R) and lower leaf nitrogen content (N
area) in low-light than in high-light environments, but an ecological significance of this trait has not been explained from a whole-plant perspective. This study aimed to theoretically and experimentally demonstrate whether these observed L/R and N
area are explained as optimal biomass allocation that maximize whole-plant relative growth rate (RGR). We developed a model which predicts optimal L/R and N
area in response to nitrogen and light availability. In the model, net assimilation rate (NAR) was determined by light-photosynthesis curve, light availability measured during experiments, and leaf temperature affecting the photosynthesis and leaf dark respiration rate in high and low-light environments. Two pioneer trees, Morus bombycis and Acer buergerianum, were grown in various light and nitrogen availabilities in an experimental garden and used for parameterizing and testing the model predictions. They were grouped into four treatment groups (relative photosynthetic photon flux density, RPPFD 100% or 10%×nitrogen-rich or nitrogen-poor conditions) and grown in an experimental garden for 60 to 100 days. The model predicted that optimal L/R is higher and N
area is lower in low-light than high-light environments when compared in the same soil nitrogen availability. Observed L/R and N
area of the two pioneer trees were close to the predicted optimums. From the model predictions and pot experiments, we conclude that the pioneer trees, M. bombycis and A. buergerianum, regulated L/R and N
area to maximize RGR in response to nitrogen and light availability. 相似文献
16.
Lu-lu Song Jiang-wen Fan Warwick Harris Shao-hong Wu Hua-ping Zhong Yong-chun Zhou Ning Wang Xu-dong Zhu 《Plant Ecology》2012,213(1):89-101
Community structure and leaf traits are important elements of terrestrial ecosystems. Changes of community structure and leaf
traits are of particular use in the study of the influence of climate change on terrestrial ecosystems. Patterns of community
structure (including species richness, above- and below-ground biomass) and leaf traits (including leaf mass per area (LMA),
nitrogen content both on mass and area bases (N
mass and N
area), and foliar δ13C) from 19 grassland plots along an altitudinal transect at Hongchiba in Chongqing, China, were analyzed. Species richness
along the altitudinal transect had a hump-shaped pattern. Above-ground biomass had a quadratic decrease along the altitudinal
gradient whereas below-ground biomass had the opposite pattern. Change of above-ground biomass of various taxonomic groups
with altitude was also studied. Poaceae showed strong negative relationships and Asteraceae showed a hump-shaped relationship
with increase of altitude. Five common species of the grassland, Trifolium pratense, Geranium wilfordii,
Aster tataricus, Leontopodium leontopodioides, and Spiraea prunifolia, were particularly studied for variation of leaf traits along the altitudinal gradient. Averaged for all species, LMA, N
area and foliar δ13C had positive correlations with altitude. N
mass did not change significantly as altitude increased. LMA and N
area showed significant positive relationships with foliar δ13C. The adaptive features of leaf traits among different species were not consistent. The study highlights specific adaptation
patterns in relation to altitude for different plant species, provides further insights into adaptive trends of community
structure and leaf traits in a specific ecological region filling a gap in the definition of global patterns, and adds to
the understanding of how adaptive patterns of plants may respond to global climate change. 相似文献
17.
Leaf nitrogen content per area (Narea) is a good indicator of assimilative capacity of leaves of deciduous broad-leaved trees. This study examined the degrees of increase in Narea in response to canopy openings as leaf mass per area (LMA) and leaf nitrogen content per mass (Nmass) in saplings of eight deciduous broad-leaved tree species in Hokkaido, northern Japan. Five of the species were well-branched species with a large number of small leaves (lateral-growth type), and the other three species were less-branched species with a small number of large leaves (vertical-growth type). The degrees of increase in Narea were compared between the two crown types. In closed-canopy conditions, leaves of the vertical-growth species tended to have a lower LMA and higher Nmass than those of the lateral-growth species, which resulted in similar Narea for both. LMA increased in canopy openings in the eight species, and the degrees of increase were not largely different between the lateral- and vertical-growth species. On the contrary, Nmass was unchanged in canopy openings in the eight species. As a result, Narea of each species increased in canopy openings in proportion to the increase in LMA, and the degrees of increase in Narea were similar in the lateral- and vertical-growth species. Therefore, this study showed that the degrees of increase in Narea were not correlated with the crown architecture (i.e., the lateral- and vertical-growth types). 相似文献
18.
Guohong Wang 《植被学杂志》2007,18(4):563-570
Question: Is there any generality in terms of leaf trait correlations and the multiple role of leaf traits (response to and/or effect on) during secondary succession? Location: A secondary successional sere was sampled at four different ages since abandonment from several years to nearly 150 years on the Loess Plateau of northwestern China. Method: Specific leaf area (SLA), leaf mass per area (LMA), leaf nitrogen (Nmass, Narea), leaf phosphorus (Pmass, Parea) and leaf dry matter content (LDMC) were measured for all species recorded in the successional sere. Above‐ground net primary productivity (ANPP) and specific rate of litter mass loss (SRLML) were measured as surrogates for ecosystem properties. Soil total carbon (C) and nitrogen (N) were measured in each stage. Leaf traits were related to ecosystem properties and soil nutrient gradients, respectively. Results: LMA is correlated with Narea and Parea' and negatively with Nmass. Correlation between Narea and Parea was higher than between Nmass and Pmass. At the community level, field age, community hierarchy and their interaction explain 64.4 ‐ 93.5% of the variation in leaf traits. At the species level, field age explains 22.4 ‐ 45.5% of the variation in leaf traits (excl. Parea) while plant functional group has a significant effect only for Nmass. LDMC is correlated with ANPP and negatively with SRLML; Pmass is correlated with SRLML. Conclusions: Mean values of LMA, Nmass and Narea are close to the worldwide means, suggesting that large‐scale climate has a profound effect on leaf mass and leaf nitrogen allocation, while environmental gradients represented by succession have little influence on leaf‐trait values. Correlations between leaf traits, such as LMA‐Narea, LMA‐Parea and LMA‐Nmass shown in previous studies, are confirmed here. Although none of the leaf traits is proved to be both a response trait and an effect trait independent of time scale and community hierarchy, mass‐based leaf N is likely a sensitive response trait to soil C and N gradients. In addition, LDMC can be a marker for ANPP and SRLML, while mass‐based leaf P can be a marker for SRLML. 相似文献
19.
J. Čatský J. Pospíšilová M. Kamínek A. Gaudinová J. Pulkrábek J. Zahradníček 《Biologia Plantarum》1996,38(4):511-518
Foliar sprays withN 6-(m-hydroxybenzytyadenosine, (mOH)-[9R]BAP, one of the synthetic cytokinins, were applied to field-grown sugar beet twice during the vegetation period: before full canopy closing(I), 6 weeks before harvest(II) or both. Application of (mOH)[9R]BAP retained high cytokinin content that usually declines prior to harvest. The total content of isoprenoid cytokinins at harvest was 2.6-fold higher in (mOH)[9R]BAP-treated plants as compared to the controls. TreatmentI had no significant effect on contents of chlorophylls (Chl)a andb and carotenoids, nor on the rates of net photosynthesis (PN) or photorespiration (Rl), or on CO2 compensation concentration (Γ) measured during the whole vegetation period on detached leaves under optimum environmental conditions. Increased values in PN, RL and Chla andb contents were found in variantsII and I+II linked with a delay in leaf senescence before harvest. Transpiration rate and stomatal conductances of adaxial and abaxial epidermes were not significantly affected by any treatment. 相似文献
20.
叶功能性状与植物的生长对策及资源利用效率密切相关,研究叶功能性状沿气候梯度的变异特征能为理解植物对气候变化的响应机制提供一种简便可行的测定指标。以我国西北荒漠地区广泛分布的唐古特白刺(Nitraria tangutorum)为研究对象,对其比叶面积(SLA)、单位质量和单位面积叶氮含量(Nmass、Narea)、单位质量和单位面积叶建成成本(CCmass、CCarea)进行测定,分析这些叶功能性状及性状相关关系沿气候梯度的变异特征。结果表明,唐古特白刺叶功能性状(CCarea除外)在气候梯度下存在显著差异,其中,温度是决定唐古特白刺SLA变化的主要因子,SLA随着温度的增加而增加;降水和温度对唐古特白刺Nmass、Narea和CCmass均有显著影响,Nmass和Narea随着降水和温度的增加而降低,而CCmass呈增加趋势。沿气候梯度,唐古特白刺SLA-Nmass、CCmass-Nmass和CCarea-Narea的线性正相关关系发生平移,导致在相同SLA、CCmass和CCarea下,降水和温度较低的地区具有更高的Nmass和Narea。这一结果表明唐古特白刺能通过调节叶功能性状之间的关系来适应气候的变化,并形成性状间的最佳功能组合。 相似文献