常绿阔叶林8种乔灌木叶片氮含量及其分配与光合能力的关系

以浙江天童国家森林公园常绿阔叶林为研究对象,采用空间代替时间的方法,研究了5个不同演替阶段常见的4种乔木以及4种灌木叶片的光饱和速率(Pmax)、光合氮素利用效率(PNUE)及其与叶片氮含量(NL)、叶片氮素在细胞壁的分配比例(细胞壁N/叶片总N,NCW/NL)、氮素在光合酶中的分配比例(NR/NL)、单位面积叶干重(LMA)的相互关系。结果表明:(1)演替系列4种乔木和4种灌木各种间指标除NL外均表现出显著差异,前期种较后期种具有更高的NR/NL、PNUE、Pmax,而后期种LMA、NCW/NL、MCW/ML(细胞壁干重/叶片总干重)更大,NL在乔木各种间差异不明显,在灌木种间则差异显著;乔木种较灌木种具有更大的LMA、NCW/NL、MCW/ML,而NR/NL则较灌木小;8种植物的Pmax与NL以杨梅为最高,连蕊茶最低;苦槠具有最高的PNUE,而栲树最低。(2)随着演替的进行,前期种的NR/NL、PNUE、Pmax有减小趋势,而LMA、NCW/NL、MCW/ML逐渐增大,后期种则表现出相反的趋势。(3)NR/NL与Pmax、PNUE之间呈显著正相关关系,而LMA、NCW/NL、MCW/ML则与Pmax、PNUE、NR/NL显著负相关。研究认为,NR/NL与NCW/NL之间的负相关性及其对PNUE的影响可以在一定程度上解释树木在光合与维持两方面的权衡关系以及演替的生理机制。     

山西霍山不同功能型植物叶性特征的比较研究

选取山西霍山地区30种主要植物（乔木7种、灌木10种、草本植物13种）,分别测定了其比叶面积（SLA）,单位重量叶氮含量（Nmass）及单位面积叶氮含量（Narea）,初步探讨了3种功能型植物的部分叶性特征,并进行了比较分析。结果表明：在霍山地区这个特定的环境下,草本植物的SLA最大,灌木次之,乔木最小;对于Nmass,同样是草本植物最高,灌木次之,乔木最低;而Narea乔木最高,灌木次之,草本最低,表现出在相同环境下,不同功能型植物的叶性特征的差异性。不同功能型植物的SLA与Nmass呈正相关关系,与Narea呈负相关关系,表现出在相同环境下,不同功能型植物叶性关系的相似性。     

黄土高原油松和刺槐叶片光合生理适应性比较

以黄土高原地区由南向北分布的杨凌、永寿、富县、安塞、米脂、神木等县为研究地点，研究不同地区油松和刺槐的光合特性与叶结构性状间的关系.结果表明，不同地区油松针叶和刺槐叶片的净光合速率（P_n）、光合氮利用效率（PNUE）、水分利用效率（WUE）、比叶质量（LMA）、氮含量（N_mass）和叶绿素相对含量（Chl）差异均达极显著水平（P＜0.001）,说明不同地区油松和刺槐的光合能力和叶结构性状参数差异很大.由南向北，油松的P_n、WUE和PNUE呈略微增加趋势，而刺槐则呈显著降低趋势，表明油松在干旱生境下仍能维持较高的光合能力，而刺槐光合能力明显受到抑制；油松和刺槐的LMA均呈略微上升趋势，而N_mass和Chl均呈略微下降趋势，且刺槐的变化幅度高于油松，说明油松从生理代谢和叶结构性状上对干旱环境的适应能力均强于刺槐.相关分析表明，不同地区油松和刺槐的LMA与N_mass整体上呈极显著负相关；P_n、PNUE与LMA、N_mass相关不显著，与Chl呈极显著正相关；WUE与LMA呈显著负相关（P＜0.05），与N_mass呈显著正相关.     

黄土高原水蚀风蚀交错带不同生境植物的叶性状

研究不同生境和不同植被演替阶段的叶性状,将为区域植被建设提供重要科学指导。以黄土高原水蚀风蚀交错带的典型区——神木六道沟流域为研究地点,研究了不同生境植物叶性状的种间和种内差异、退耕地植被演替过程中叶性状的变化及其相互关系。结果表明:(1)不同生境植物的光合特征和叶片结构特征的种间差异较大,这可能是植物长期适应生态环境的结果,同时也与其本身固有的遗传特性有关。(2)在物种水平上,最大光合速率(Pmax)、光合氮素利用效率(PNUE)和比叶面积(SLA)随退耕年限的增加呈显著下降趋势,而水分利用效率(WUE)、叶氮含量(Nmass)与退耕年限相关关系不显著。在群落水平上,除SLA与退耕年限的相关性不显著以外,其它指标皆与物种水平的变化趋势一致。(3)研究区32个物种的Pmax与WUE、PNUE、Nmass呈显著正相关(P0.05),而与SLA的相关关系不显著。PNUE与WUE、SLA呈显著正相关(P0.001),而与Nmass的相关性不显著;物种的Nmass与SLA呈显著正相关(P0.001)。同其它地区相比,研究区物种的Pmax、PNUE、SLA较低。具有较低Pmax、PNUE、SLA的物种可能更适宜研究区土壤贫瘠的生境。     

南亚热带人工林16种木本植物重要叶特征参数的相互关系

以南亚热带退化丘陵生态恢复进程中16种3 a生木本植物为对象,研究叶片重要特征参数间的相互关系.结果表明,植物叶片的N、P含量平均值低于全国平均值,N:P平均值则高于全国的平均水平;成熟叶片的N和P含量之间有极显著正相关关系(P<0.00001),N:P与N有弱的正相关关系(r=0.322,P<0.01),与P显著负相关,推断植物叶N:P主要由P决定(r=0/639,P<0.00001).含N量高的植物具有高的最大净光合速率(Pmax)、光合N利用效率(PNOE)和低的比叶重(LMA),反之,含N量低植物具有低的Pmax、PNUE和高的LMA;Pmax与PNUE极显著正相关,LMA与PNUE极显著负相关.     

8种阔叶树种叶片气体交换特征和叶绿素荧光特性比较

在自然条件下,测定了8种阔叶树种叶片的气体交换参数和叶绿素荧光参数并对其进行比较.结果表明,8种阔叶树种紫玉兰、广玉兰、玉兰、美人梅、铁杆梅、腊梅、红碧桃和紫薇的叶片净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（gs）、瞬时水分利用效率（WUE）和潜在水分利用效率（WUEi）的种间差异达极显著水平（p〈0.01）,指示了不同树种间的光合能力及水分利用能力差别较大.8种阔叶树种叶片的初始荧光（Fo）、可变荧光（Fv）、最大荧光（Fm）和PSⅡ电子传递量子效率（ФPSⅡ）的种间差异极为显著（p〈0.01）,PSⅡ最大光能转换效率（Fv/Fm）、可变荧光与初始荧光之比（Fv/Fo）和非光化学猝灭系数（NPQ）的种间差异也达显著水平（p〈0.05）,说明各树种叶片的PSⅡ原初光能转换效率和潜在活性、PSⅡ电子传递量子效率以及PSⅡ的潜在热耗散能力差别较大,而实际光下最大荧光（F′m）和PSⅡ光能捕获效率（F′v/F′m）的种间差异不显著.3种木兰科植物的Pn、Tr、WUE和WUEi平均值均高于3种蔷薇科植物,说明木兰科植物的光合能力较强,对吸收的光能和水分的利用较高.蔷薇科植物的Fv/Fm、Fv/Fo、ФPSⅡ、F′v/F′m和光化学猝灭系数（qp）平均值均高于木兰科植物,而木兰科植物NPQ较高,表明其PSⅡ的潜在热耗散能力较强,可有效地避免过剩光能对光合机构的损伤.研究还表明3种木兰科植物和3种蔷薇科植物之间的叶绿素荧光参数差异不大,说明同一科属植物叶片的光合能力较为相近.相关分析表明,8种阔叶树种叶片的Pn与Tr、Tr与gs、Fv/Fm与Fv/Fo、ФPSⅡ与F′v/F′m、qp与NPQ均呈极显著正相关（p〈0.01）,Pn与gs呈显著正相关（p〈0.05）,而Tr、gs与WUE、WUEi,Pn与ФPSⅡ,ФPSⅡ与NPQ,F′v/F′m 与 qp、NPQ均呈极显著负相关（p〈0.01）.     

北京植物园不同功能型植物叶经济谱

通过对北京植物园不同功能型植物的叶片光合参数、叶绿素荧光参数、叶面积、叶干质量以及叶氮含量等性状参数进行测定,分析了不同功能型植物的叶经济谱.结果表明: 生活型中草本植物、生活史中一年生植物、光合型中C4植物靠近叶经济谱中快速投资-收益型物种的一端,而生活型中乔木和灌木、生活史中多年生植物、光合型中C3植物位于缓慢投资-收益型物种的一端,表明不同功能型植物通过叶片性状间的权衡采取不同的环境适应策略,验证了不同功能型植物叶经济谱的存在.不同功能型植物叶片性状具有明显差异,其中不同生活型间的叶片比叶面积(SLA)、叶氮含量(N_mass)、最大净光合速率(A_mass)、光合氮利用效率(PNUE)均表现出草本植物>藤本植物>灌木>乔木;不同生活史间一年生植物的SLA、N_mass、A_mass、PNUE均显著高于多年生植物;不同光合型间植物的A_mass、PNUE、PSⅡ实际光化学效率(Φ_PSⅡ)均表现出C4>C3.N_mass、A_mass、SLA两两之间呈显著正相关,而PSⅡ有效光化学量子产量(F_v′/F_m′)与SLA呈显著负相关;PNUE与SLA呈显著正相关.     

氮磷添加对金露梅叶片化学计量及光合特征的影响

通过三种养分添加处理,氮添加(5、10和15 g??m-2)、磷添加(梯度同氮添加)、氮磷同时添加[(5 g N＋5 g P)??m-2、(10 g N＋10 g P)??m-2、(15 g N＋15 g P)??m-2],对照(无养分添加),探讨养分添加对金露梅叶片性状氮含量(Nmas )、磷含量(Pmas )、氮磷比(N∶P)、比叶重(LMA)、净光合速率(Pn )和光合氮利用效率(PNUE)的影响,以及各性状之间的相互关系.结果表明：在处理水平上,除N或P显著提高金露梅叶片的N∶P外,氮、磷添加对叶片其它性状无显著影响;不同氮、磷处理下添加水平对金露梅叶片的Nmas、N∶P、Pn和PNUE均有显著影响,随着养分水平提高,各性状的变化模式各不相同,叶片Pmas无明显变化,而叶片LMA虽有降低的趋势但不显著.回归分析表明,叶片Pmas与Nmas之间呈显著正相关(R2＝0．347,P＜0．001),叶片Nmas 与N∶P之间也呈显著正相关(R2＝0．018,P＜0．05),而叶片Pmas与N∶P呈显著负相关(R2＝0．505,P＜0．001);叶片LMA与Pn之间显著负相关(R2＝0．02,P＜0．05),而与PNUE之间显著正相关(R2＝0．077,P＜0．001).这表明在一定范围内,环境变化可以改变金露梅叶片的养分保持能力、光合能力以及养分利用效率.     

太岳山典型阔叶乔木冠层叶片性状的分布格局

以太岳山4种阔叶乔木不同冠层高度的叶片为研究对象,用LI-3000A叶面积仪和Li-6400便携式光合作用测定系统分别测定了这4种乔木不同冠层高度叶片的叶面积大小和单位面积的叶光饱和速率(Aarea);同时测定了其叶氮含量;计算了其比叶面积(SLA)、单位面积叶氮含量(Narea)、单位重量叶氮含量(Nmass)、单位重量的叶光饱和速率(Amass)和光合氮素利用效率(PNUE),对植株不同冠层高度叶片的SLA、叶氮和光合特性的空间分布格局进行了比较研究,结果表明:Aarea、Amass、Nmass、PNUE、SLA和Narea在树冠上层、中层和下层的差异均达到了极显著水平(P<0.001),表明树冠不同高度的叶片性状参数差异较大;在相同SLA下,Nmass和Narea在冠层中的分布均表现为中层>上层>下层,并出现平行位移现象;Aarea和Nmass都以中层值最大,表明冠层光合能力分布格局以中层相对较高。     

干旱和湿润生境中主要优势树种叶片功能性状的比较

以云南南部的沟谷雨林(湿润生境)和干热河谷萨瓦纳(savanna)稀树灌丛(干旱生境)中共31种主要优势木本植物为材料,研究了叶片主要功能性状单位面积叶干重(LMA)、单位干重氮含量(Nmass)和单位干重最大净光合速率(Amass)在2个生境中的差异及各性状间的关系。结果表明:在物种水平上,干旱和湿润生境中各树种的LMA值分别为46.88～178.63和45.35～93.16g·m-2;Amass值分别为48.12～176.65和71.38～265.76nmol·g-1·s-1;Nmass值分别为11.8～36.71和12.98～31.78mg·g-1;在群落水平上,干旱生境中LMA显著高于湿润生境,而Amass显著低于湿润生境,Nmass在2个生境中差异不显著;在群落尺度上,干旱生境中LMA与Nmass和Amass均呈显著负相关;在2生境中Nmass与Amass均呈显著正相关。同一生境下不同植物对环境的适应策略有差异,但各性状间的相关关系具有趋同性;从湿润到干旱生境,植物由快速生长转向以提高资源利用效率为主的适应策略。     

Apple leaf senescence: leaf disc compared to attached leaf

Attached apple leaves (Pyrus malus L., Golden Delicious) began to lose protein in early August as the first sign of senescence. Apple leaf discs prepared from samples before early August gained protein for up to 7 days after detachment. After early August, the loss of protein from leaf discs was no greater than the loss from attached leaves in 7 days. The loss of chlorophyll from leaf discs began over 2 months before attached leaves began to lose chlorophyll naturally and before leaf discs lost protein. Leaf discs from presenescent leaves did not senesce significantly faster when maintained in darkness instead of 12 hours of light. In general, the loss of protein and chlorophyll from apple leaf discs after 7 days was much less than for most other leaf types studied.     

Intraspecific variation in spring leaf phenology and duration of leaf expansion in relation to leaf habit and leaf size of temperate tree species

Plant Ecology - Spring leaf phenology has been intensively studied in temperate deciduous broad-leaved tree species, but the phenology of evergreen broad-leaved tree species has seldom been focused...     

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R _d) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A _max). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R _d measured at a standard temperature and leaf life-span, N, SLA and A _max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R _d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R _d (R _d-mass) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A _max and leaf N (leaf N _mass). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R _d-mass−N _mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R _d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R _d-mass was well predicted by all combinations of leaf life-span, N _mass and/or SLA (r ²≥ 0.79, P < 0.0001). At any given SLA, R _d-mass rises with increasing N _mass and/or decreasing leaf life-span; and at any level of N _mass, R _d-mass rises with increasing SLA and/or decreasing leaf life-span. The relationships between R _d and leaf traits observed in this study support the idea of a global set of predictable interrelationships between key leaf morphological, chemical and metabolic traits. Received: 23 May 1997 / Accepted: 16 December 1997     

The effects of leaf size,leaf habit,and leaf form on leaf/stem relationships in plant twigs of temperate woody species

Question: Do thick‐twigged/large‐leaf species have an advantage in leaf display over their counterparts, and what are the effects of leaf habit and leaf form on the leaf‐stem relationship in plant twigs of temperature broadleaf woody species? Location: Gongga Mountain, southwest China. Methods: (1) We investigated stem cross‐sectional area and stem mass, leaf area and leaf/lamina mass of plant twigs (terminal branches of current‐year shoots) of 89 species belonging to 55 genera in 31 families. (2) Data were analyzed to determine leaf‐stem scaling relationships using both the Model type II regression method and the phylogenetically independent comparative (PIC) method. Results: (1) Significant, positive allometric relationships were found between twig cross‐sectional area and total leaf area supported by the twig, and between the cross‐sectional area and individual leaf area, suggesting that species with large leaves and thick twigs could support a disproportionately greater leaf area for a given twig cross‐sectional area. (2) However, the scaling relationships between twig stem mass and total leaf area and between stem mass and total lamina mass were approximately isometric, which indicates that the efficiency of deploying leaf area and lamina mass was independent of leaf size and twig size. The results of PIC were consistent with these correlations. (3) The evergreen species were usually smaller in total leaf area for a given twig stem investment in terms of both cross‐sectional area and stem mass, compared to deciduous species. Leaf mass per area (LMA) was negatively associated with the stem efficiency in deploying leaf area. (4) Compound leaf species could usually support a larger leaf area for a given twig stem mass and were usually larger in both leaf size and twig size than simple leaf species. Conclusions: Generally, thick‐twigged/large‐leaf species do not have an advantage over their counterparts in deploying photosynthetic compartments for a given twig stem investment. Leaf habit and leaf form types can modify leaf‐stem scaling relationships, possibly because of contrasting leaf properties. The leaf size‐twig size spectrum is related to the LMA‐leaf life span dimension of plant life history strategies.     

Wheat leaf photosynthesis loss due to leaf rust, with respect to lesion development and leaf nitrogen status

In wheat (Triticum aestivum cv. Soissons) plants grown under three different fertilisation treatments, we quantified the effect of leaf rust (Puccinia triticina) on flag leaf photosynthesis during the whole sporulation period. Bastiaans' model: Y = (1 - x)beta was used to characterize the relationship between relative leaf photosynthesis (Y) and disease severity (x). The evolution of the different types of symptoms induced by the pathogen (sporulating, chlorotic and necrosed tissues) was evaluated using image analysis. The beta-values varied from 2 to 11, 1.4-2, and 0.8-1 during the sporulation period, when considering the proportion of sporulating, sporulating + necrotic, and total diseased area, respectively. Leaf nitrogen (N) content did not change the effect of the disease on host photosynthesis. We concluded that leaf rust has no global effect on the photosynthesis of the symptomless parts of the leaves and that the large range in the quantification of leaf rust effect on the host, which is found in the literature, can be accounted for by considering the different symptom types. We discuss how our results could improve disease assessments and damage prediction in a wheat crop.     

Nitrogen fertilization effects on leaf morphology and evaluation of leaf area and leaf area index prediction models in sugar beet

In a two-year experiment (2002–2003), five N application rates [0, 60, 120, 180, and 240 kg(N) ha⁻¹, marked N₀, N₆₀, N₁₂₀, N₁₈₀, and N₂₄₀, respectively] were applied to sugar beet cv. Rizor arranged in a Randomized Complete Block design with six replications. Leaf shape parameters [leaf area (LA), maximum length (L), maximum width (W), average radial (AR), elongation (EL), and shape factor (SF)] were determined using an image analysis system, and leaf area index (LAI) was non-destructively measured every two weeks, from early August till mid-September (four times). Years, samplings, and their interaction had significant effects on the determined parameters. Fertilization at the highest dose (N₂₄₀) increased L and sampling×fertilization interaction had significant effects on LA, L, W, and SF. For this interaction, W was the best-correlated parameter with LA and LAI meaning that W is a good predictor of these parameters. Two proposed models for LA estimation were tested. The model based on both leaf dimensions [LA = 0.5083 (L×W) + 31.928] predicted LA better than that using only W (LA = 21.686 W − 112.88). Instrumentally measured LAI was highly correlated with predicted LAI values derived from a quadratic function [LAI = −0.00001 (LA)² + 0.0327 LA − 2.0413]. Thus, both LA and LAI can be reliably predicted non-destructively by using easily applied functions based on leaf dimensions (L, W) and LA estimations, respectively.     

石斛属植物叶片生物量与叶片养分含量间的关联进化

叶片生物量和元素含量是显著影响叶片生理功能的两类重要的叶片经济性状, 且二者紧密相关。然而过去的研究多数关注C、N和P三种元素含量, 而对其他元素含量关注较少。维管附生植物不能直接从土壤中吸收养分而经常遭受养分胁迫, 养分含量与生物量之间的协同关系在这类植物中表现得尤为突出。选择维管附生石斛属植物为研究对象, 应用系统发育独立对比分析, 检测了叶片生物量和元素含量的系统发育保守性以及这些性状间的关联进化。结果表明, 叶片干物质含量、比叶重、C含量、N含量、P含量以及C/N具有较强的系统发育信号, 并且叶片干物质含量和比叶重与这四个元素含量性状间存在较强的关联进化。另外, 经系统发育校准后, Ca含量和Mg含量间存在显著正相关; P含量与Si含量间存在显著正相关; Zn含量与N含量、N/P以及Mn含量间存在显著正相关, 而与C/N间存在显著负相关。结果为探讨维管附生植物叶片生物量和元素含量的主要影响因素, 以及从进化角度探讨二者在植物进化适应过程中的生态协同功能提供案例, 对进一步了解维管附生植物的功能适应性具有重要意义。