49 resultados para leaf area
Some quantitative relationships between leaf area index and canopy nitrogen content and distribution
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In order to examine the role of environmental factors affecting foliar morphology, we performed a case study of leaf morphological variation of Ranunculus natans found in the arid zone of northwest China. We found that foliar phenotypic variation differed significantly between populations. We described substantial positive correlations between altitude and leaf area (LA) as well as leaf perimeter (LP), and also between longitude and number of teeth, along with dissection index (DI). The pH, conductivity, and salinity of the environment caused a significant decrease in both LA and LP. Ranked in terms of their impacts on leaf morphology, the six selected factors were: altitude > pH > conductivity > salinity > longitude > latitude. We found that foliar morphological variations are functional responses to water-quantity factors (e.g., altitude and longitude at regional scales) and water-availability relation factors (e.g., pH, conductivity, and salinity at local scales), rather than to temperature-relation factors (latitude). Therefore, altitude and longitude, along with pH, conductivity, and salinity, are the main factors that significantly influence foliar morphology in the arid zone of China. We found that main factors played major roles in plant phenotypic plasticity in a complex ecosystem, although different combinations and interactions of environmental and geographical factors in each local environment may obscure the general trends in trait changes along environmental gradients.
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In many plant species, leaf morphology varies with altitude, an effect that has been attributed to temperature. It remains uncertain whether such a trend applies equally to juvenile and mature trees across altitudinal gradients in semi-arid mountain regions. We examined altitude-related differences in a variety of needle characteristics of juvenile (2-m tall) and mature (5-m tall) alpine spruce (Picea crassifolia Kom.) trees growing at altitudes between 2501 and 3450 m in the Qilian Mountains of northwest China. We found that stable carbon isotope composition (delta C-13), area- and mass-based leaf nitrogen concentration (N-a, N-m), number of stomata per gram of nitrogen (St/N), number of stomata per unit leaf mass (St/LM), projected leaf area per 100 needles (LA) and leaf mass per unit area (LMA) varied nonlinearly with altitude for both juvenile and mature trees, with a relationship reversal point at about 3 100 m. Stomatal density (SD) of juvenile trees remained unchanged with altitude, whereas SD and stomatal number per unit length (SNL) of mature spruce initially increased with altitude, but subsequently decreased. Although several measured indices were generally found to be higher in mature trees than in juvenile trees, N-m, leaf carbon concentration (C.), leaf water concentration. (LWC), St/N, LA and St/LM showed inconsistent differences between trees of different ages along the altitudinal gradient. In both juvenile and mature trees, VC correlated significantly with LMA, N-m, N-a, SNL, St/LM and St/N. Stomatal density, LWC and LA were only significantly correlated with delta C-13 in mature trees. These findings suggest that there are distinct ecophysiological differences between the needles of juvenile and mature trees that determine their response to changes in altitude in semi-arid mountainous regions. Variations in the fitness of forests of different ages may have important implications for modeling forest responses to changes in environmental conditions, such as predicted future temperature increases in high attitude areas associated with climate change.
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氮素是大多数陆地生态系统初级生产力的主要限制因子。由于人类的工业和农业生产活动不断加剧,导致全球性氮沉降增加,使大多数生态系统氮素的可获得性增强。从而降低或消除了氮素对生态系统的限制作用,加速了生态系统生物地球化学过程,对物种多样性和生态系统结构与功能产生了显著的影响。但由于成土母质、气候条件、地形地貌、植被组成等的差异,不同生态系统类型对氮素增加的响应也不尽相同。欧洲和北美一些发达国家地区对于草地生态系统对于全球性氮沉降增加响应进行了较全面的研究,对于分布广泛的欧亚大陆草原研究相对不足。 本文研究选择对于欧亚大陆草原较具代表性的成熟羊草草原群落及该群落的退化类型为研究对象,从1999年开始,在这两类群落中选取地形相对平缓均一,植被组成一致的地段设置了施肥小区并进行持续氮素添加实验。本文研究了成熟和退化羊草草原群落物种功能特性与土壤微生物量C、N、P对氮素添加响应。 羊草群落中6种主要植物的地上生物量、种群密度、比叶面积、叶氮和叶绿素含量对于氮素添加响应以及各指标之间相关关系的分析表明:比叶面积、基于质量的叶片含氮量和叶绿素含量、叶绿素a和叶绿素b的比值等叶片水平上物种功能特性间的相互作用,共同影响和决定了种群密度和地上生物量对氮素添加的响应。羊草通过提高比叶面积、叶片叶绿素含量和含氮量、种群密度及个体生物量等多重调节功能对氮素添加做出响应。西伯利亚羽茅主要通过提高比叶面积、单位质量叶片的叶绿素含量和含氮量,以及株丛生物量,使其在群落占据优势。大针茅和冰草在提高比叶面积、叶片叶绿素含量和含氮量的调节能力相对较低,种群密度沿氮素添加梯度显著降低。黄囊苔草只能通过提高叶片叶绿素含量和含氮量对氮素添加做出响应,其叶绿素a与叶绿素b的比值沿氮素添加梯度逐渐降低,种群密度和地上生物量也显著降低。糙隐子草的叶绿素a与叶绿素b比值沿氮素添加梯度显著降低,但由于糙隐子草具有较高的SLA,且对叶绿素、叶片含氮量的调节能力较强,氮素添加处理没有对其种群密度和地上生物量产生显著的影响。上述结果支持Tilman的光资源竞争假说和Knops等的物种替代假说。 成熟和退化羊草群落土壤微生物量、土壤有机碳、全氮、全磷、速效氮、pH以及凋落物碳、氮、磷含量的测定结果表明:(1)成熟羊草群落表层土壤微生物量碳、氮、磷含量均随氮素添加量的增加而降低;退化羊草群落表层土壤微生物量碳、氮、磷含量沿氮素梯度表现出先增加而后降低的趋势;相关分析的结果显示各群落土壤微生物量碳、氮、磷均与土壤pH呈显著的正相关。(2)微生物量碳、氮、磷含量均随土层深度的增加而下将;而对照的微生物量碳、氮、磷含量则与土壤有机质含量呈显著正相关。(3)年度间降水量差异对土壤微生物量碳、氮、磷具有较大影响。综合上述研究结果,我们认为成熟羊草群落土壤微生物生长不受氮素限制,但退化群落不同;氮素添加导致的土壤酸化作用可能是两类群落表层土壤微生物量下降的主要因素,且这种影响主要集中在0-10cm的表层土壤;表层土壤微生物量碳、氮、磷对氮素添加的响应可能还受到其它因子(如生长季降水量)的影响;深层土壤微生物量较低主要是由于土壤有机质含量较低的缘故。
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以辽东栎(Quercus liaotungensis)为主的落叶阔叶林、华北落叶松林(Larix principisrupprechtii)和油松(Pinus tabulaeformis)林是我国暖温带地区具有代表性的森林群落类型。本研究:1)应用国内外流行的半球图方法,通过对这三种森林群落叶面积指数和林冠开阔度的测定和综合比较,分析了叶面积指数和林冠开阔度的季节动态,揭示了暖温带地区不同类型森林群落叶面积指数和林冠开阔度的特征;2)基于野外调查的样地资料,利用维量分析法估算了中国科学院北京森林生态系统定位研究站三种森林群落乔木层的生物量和生产力,并揭示生产力和叶面积指数之间的相关关系;3)利用油松森林群落和落叶松森林群落采集树芯作为研究对象,用树木年轮学方法,建立相应的年表,联系气候资料进行相关分析,揭示树木生长的限制因子。 研究结果表明:1)落叶阔叶林(优势种为:辽东栎、棘皮桦(Betula dahurica)、五角枫(Acer mono))和华北落叶松林两种落叶森林群落的叶面积指数值均随生长季的到来而呈现增长的趋势,最大值出现在8月;林冠开阔度值随着生长季的到来而下降,最大值出现在11月。落叶阔叶林的叶面积指数和林冠开阔度的季节动态较之华北落叶松林明显。油松是常绿树种,其群落叶面积指数和林冠开阔度的变化程度均不明显,但林冠开阔度的变化趋势也是与叶面积指数的变化趋势相反。通过计算得出叶面积指数和林冠开阔度相关显著,并且呈现指数回归的关系。2) 油松、落叶松、落叶阔叶林三种森林群落乔木层的生物量和生产力分别为93.59 t•hm-2、119.36 t•hm-2 、169.94 t•hm-2和4.02 t•hm-2•a-1、5.58 t•hm-2•a-1、7.04 t•hm-2•a-1;三种森林群落乔木层生产力和叶面积指数回归曲线分析显示,生产力和叶面积指数呈现线性正相关关系。3)油松和落叶松生长与气候因子相关分析结果显示,两种群落树木的生长受当地降水和气温的影响,油松与5月份的温度显著负相关,落叶松与2月份和5月份的降水显著正相关。 以上研究结果为以遥感途径获取暖温带地区叶面积指数提供了地面校正依据,为研究该地区利用LAI估算生产力以及利用遥感途径得到的NDVI测定生产力、研究气候因子对树木年轮宽度形成的影响,以及进一步对该地区林分、景观和区域尺度上碳、水、通量等方面的模拟提供了基础数据。
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为了探究草原植物生长策略及其对养分变化的响应,本文比较分析了克氏针茅(Stipa krylovii)、冷蒿(Artemisia frigida)和糙隐子草(Cleistogenes squarrosa)根与叶的形态特性及其对氮素添加的响应。结果表明不同植物具有不同的生长策略,糙隐子草主要采取快速获取资源的生长策略,表现为具有高的比根长和比叶面积;冷蒿则主要采取保存资源的生长策略,表现为具有较高的根组织密度和较低的比根长;克氏针茅对资源的获取和保存能力都相对较强,表现为具有较大的比根长、较小的比叶面积和中等大小的根与叶组织密度。氮素添加主要影响克氏针茅和冷蒿的根特性,随着氮素添加量的增加,克氏针茅比根长显著增加,根组织密度显著降低,说明随着氮素添加量的增多克氏针茅根系对氮素的获取能力增强,从而导致其在群落中的生物量比例显著增加。冷蒿根表面积随着氮素添加量的增多显著降低,说明随着氮素添加量的增加冷蒿根系对氮素的吸收能力下降,导致其在群落中的生物量比例随着氮素添加量的增大而减少。氮素添加没有显著地影响糙隐子草根和叶特性,它在群落中的生物量比例也没有明显规律。因此,我们研究结果证明通过植物根和叶形态特性的变化能够预测植物在群落中地位的改变。 根与叶特性之间的关系可以进一步反映植物对资源获取和保存的权衡能力,研究植物根与叶特性的内在关系有助于更全面地理解植物的生存对策,更好地预测植物对环境变化的反应。我们通过简单相关分析和典型相关分析研究了克氏针茅草原植物的根与叶特性之间的关系及其对氮素添加的响应和根与叶总体关系。简单相关分析结果表明根特性之间、叶特性之间以及根与叶特性之间均存在相关性,植物特性之间的相互关系在根与叶中是相似的,且体现了植物对资源的获取与保存的权衡关系,如根组织密度与比根长负相关,叶组织密度与比叶面积负相关等,根与叶对应指标之间没有必然的联系。施氮肥使根与叶特性之间的相关性及其强弱发生变化,表明氮素添加是影响植物根与叶特性之间关系的因素之一。典型相关分析表明不同物种根与叶关系密切程度存在差异,不同根与叶特性之间的关系对根与叶总体的关系贡献程度也有所不同。
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基于长期定位施肥试验,研究了不同施肥对冬小麦生长、产量及水分利用的影响。结果表明:不同施肥均能促进冬小麦株高、叶面积、生物量的增长,株高、叶面积、生物量均为:单施氮肥处理(N)高于不施肥处理(CK),氮磷配施处理(NP)显著高于CK和N处理,三个有机肥处理(M、NM和NPM)均较高。不同施肥对冬小麦光合速率影响显著,NPM处理的光合速率在各个生育期均最高;其次分别为NM处理和NP处理,而M处理在前期较高,后期下降较快,N和CK处理均较低。不同施肥处理小麦产量:NPM>NM>M>NP>N>CK,不同施肥均能显著增加小麦产量(增产量为341~4388kg/hm2),除M和NM处理,其他处理均有显著差异;冬小麦耗水量和水分利用效率均随施肥水平提高而增加,NPM和NP处理显著高于N和CK处理。表明在本试验年单施氮肥对小麦生长及产量影响较小,单施有机肥及不同肥料配施均能显著促进小麦生长及产量提高,有机肥的增产效应显著高于无机肥,其中NPM处理的产量及水分利用效率均最高。
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通过大田玉米试验,验证新型土壤改良剂对夏玉米生育期土壤水分、紧实度及玉米生理生长特性的影响。结果表明,施用改良剂PJG和PFL夏玉米全生育期平均株高、叶面积分别高于对照20.7%、19.75%和51.88%、72.37%;2种改良剂对干物质积累的影响存在差异,影响效果依次为茎干重>叶干重>根干重。夏玉米光合速率和叶绿素含量受土壤改良剂影响较大,PJG和PFL分别高于对照29.96%、24.48%和73.36%、68.53%。在0~10 cm土层内,施用PJG和PFL后土壤紧实度分别低于对照44.44%和42.91%。施用改良剂PJG后,0~20 cm土层土壤含水量维持在田间持水量的77.9%左右,未施用改良剂土壤,夏玉米生育期表层土壤含水量起伏变化较大。土壤改良剂PJG在夏玉米的施用效果略好于PFL。
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花椒(Zanthoxylum bungeanum)是川西干旱河谷地区重要的经济作物,化感作用是花椒连作障碍的重要原因之一。花椒凋落物分解是影响花椒林地土壤肥力及花椒产量的重要因素,因此系统研究花椒化感作用是否对花椒凋落物的分解产生影响可以为解决花椒连作障碍导致的产量下降等问题提供科学的理论依据。本文通过室内模拟实验研究了花椒凋落物的四个分解动态以及分解后凋落物浸提液对花椒林地土壤性质的影响;通过野外盆栽实验研究了花椒凋落物浸提液对花椒幼苗的生长、花椒凋落物的质量及土壤性质的影响。最终从生理生化角度揭示了花椒的化感作用对凋落物分解的影响机理,为深入解决花椒连作障碍问题、对花椒凋落物采取有效的人工措施提供了科学的理论依据。主要的研究结果如下: 1. 室内分解实验证明,花椒凋落物在分解的60 d 内分解速率呈现由大到小的变化趋势,并且凋落物分解呈现明显的毒性动态。凋落物在分解的10 d、30 d 时,分解速率较大,30 d 以后分解速率显著降低。凋落物分解的10 d 左右酚酸释放量最大,此时凋落物的毒性最大,凋落物分解到10 d 以后,酚酸释放量逐渐减少,凋落物的毒性也逐渐减小。 2. 四个分解动态的花椒凋落物浸提液对土壤化学性质产生了显著的影响。花椒凋落物在分解的60 d 内,其浸提液使土壤pH值均显著的增加。分解0 d 的凋落物浸提液显著的降低了土壤铵态氮的含量,抑制了纤维素分解菌的生长;分解60 d 的凋落物浸提液显著的降低了土壤酚酸含量,增加了土壤有效磷的含量;分解30 d 和60 d 的凋落物浸提液均显著的促进了好气性纤维素分解菌的生长。这说明花椒凋落物在分解过程中呈现出明显的毒性动态:凋落物分解的初期毒性作用较大,随着分解的继续进行特别是在分解的30 d 以后,其毒性作用慢慢降低。 3. 花椒凋落物浸提液对花椒幼苗表现出明显的化感作用。不同浓度的浸提液对花椒幼苗地上及地下生物量、叶面积均产生了显著的抑制作用,并且随着浸提液浓度的升高抑制作用加强。凋落物浸提液对叶片厚度的影响较小,只有Y1对叶片厚度的生长抑制作用显著。 4. 花椒的化感作用改变了凋落物的质量,并对凋落物分解产生了显著的影响。对花椒幼苗用不同浓度的凋落物浸提液进行处理,Y1使凋落物有机碳含量、木质素含量、C/N、木质素/氮显著降低,纤维素含量显著升高;Y3使凋落物有机碳含量、木质素含量、C/N、木质素/氮显著升高。花椒凋落物质量的改变显著的影响了凋落物的分解,凋落物的分解速率大小依次为:Y1(10.15 a-1)> Y2(8.71 a-1)> CK(6.41 a-1)> Y3(5.08 a-1)。 5. 花椒的化感作用改变了土壤性质,并对凋落物分解产生了显著的影响。对花椒幼苗用不同浓度的凋落物浸提液处理的同时,也改变了土壤性质。不同浓度的凋落物浸提液显著的升高了土壤pH值、有机碳含量。各种浓度的凋落物浸提液对土壤多酚氧化酶的活性均起到了显著的促进作用。凋落物浸提液Y1对土壤纤维素分解酶的活性、细菌和真菌的生长也具有显著的促进作用。土壤性质的改变显著的影响了凋落物的分解,凋落物的分解速率大小依次为:Y1(10.30 a-1)>Y2(9.60 a-1)>CK(6.41 a-1)>Y3(6.29 a-1)。 6. 不论是凋落物质量发生改变还是土壤性质发生改变,在凋落物分解的整个过程中,C元素始终处于单调净释放的状态,并且C释放量与分解速率成显著的正相关,即凋落物分解越快,凋落物C释放量越大。凋落物分解过程中,均出现了酚酸大量释放的情况,并与凋落物分解速率成显著正相关。凋落物分解后的木质素含量、木质素/氮均增加,并且随着浸提液浓度的升高,凋落物木质素含量、木质素/氮升高。 Zanthoxylum bungeanum is an important economic crop in dry valley of the Minjiang river (Sichuan, Southwest China), but allelopathy is one of the important reasons for its continuous cropping. Zanthoxylum bungeanum litter decomposition affects Zanthoxylum bungeanum soil fertility and its output. So systemically investigate if allelopathy affects litter decomposition could provide the scientific methods to solve the problem of output fall caused by the continuous cropping. In this paper, the releasing dynamics of phenolic acid during Zanthoxylum bungeanum litter decomposition (0, 10, 30 and 60 days) and the effects of its aqueous extract on soil chemical properties were investigated via the laboratory study. Effects of Zanthoxylum bungeanum litter aqueous extract on the growth of young Zanthoxylum bungeanum seedlings, litter qualities and the soil qualities were investigated via the field study. Finally, we open out the action manner of Zanthoxylum bungeanum allelopathic effect on the litter decomposition, and provide the theoretical basis to solve the Zanthoxylum bungeanum continuous cropping. The main results showed that: 1. The laboratory litter decomposition experiment showed a trend of decomposition rate from large to small and an occurrence of phytotoxicity with clear dynamic patterns during Zanthoxylum bungeanum litter decomposition. The litter decomposition rate was larger at the tenth and 30th day during 60-day litter decomposition and gradually decreased after 30 days of litter decompostion. The releasing quantity of the litter phenolic acid was the highest at the tenth day, and here, the litter toxicity was the biggest. The releasing quantity of the litter phenolic acid gradually decreased after 10 days of litter decomposition, so the phytotoxicity of litter was gradually decreased with the litter decomposition. 2. The Zanthoxylum bungeanum litter aqueous extract after four decomposition stages had significantly effect on the soil chemical qualities. The pH value in soil was significantly increased in litter aqueous extract of four decomposition stages. The NH+4-N concentration was significantly decreased in soil amended with litter aqueous extract of 10-day decomposition which inhibited the growth of Aerobic cellulose-decomposer. The growth of soil Aerobic cellulose-decomposer was promoted by the litter aqueous extract of 30-day decomposition. Available phosphorus concentration was significantly increased and phenolic acid content was significantly decreased in soil amended with litter aqueous extract of 60-day decomposition which promoted the growth of Aerobic cellulose-decomposer. The study results showed an occurrence of phytotoxicity with clear dynamic patterns during Zanthoxylum bungeanum litter decomposition. The phytotoxicity of litter was the largest at the initial stage, but the phytotoxicity gradually decreased with the litter decomposition, especially after 30 days of decomposition. 3. The field study indicated that the Zanthoxylum bungeanum litter aqueous extract had significant allelopathic effects on the growth of young seedlings.Different concentration aqueous extract had signinficant inhibiting effects on biomass and leaf area of young seedlings. The inhibiting effect on the biomass strengthened with the litter aqueous extract concentration augment. Litter aqueous extracts had less effect on the leaf thickness, and only Y1 had significant inhibiting effect on the leaf thickness. 4. The Zanthoxylum bungeanum allelopathy had significant effect on the litter qualities and the litter decomposition. Treating the young Zanthoxylum bungeanum seedlings with different concentration of litter aqueous extracts, the leaf litter organic C, lignin, C/N and lignin/N all decreased and the cellulose content increased under Y1 treatment. The leaf litter organic C, lignin, C/N and lignin/N all increased under Y3 treatment. So the litter decomposition was significant affectded by the litter qualities, and the litter decomposition rate was Y1(10.15 a-1)> Y2(8.71 a-1) > CK(6.41 a-1) > Y3(5.08 a-1). 5. The Zanthoxylum bungeanum allelopathy had significant effect on the soil qualities and the litter decomposition. Treating the young Zanthoxylum bungeanum seedlings with different concentration of litter aqueous extracts, also changed the soil qualities. Different concentration of litter aqueous extracts had significant effects on the soil pH and organic C content. Every concentration of litter aqueous extracts accelerated the soil Polyphenol Oxidase activity and Y1 accelerated the soil Cellulase activity, the number of soil bacteria and fungi. So the litter decomposition was significant affected by the soil qualities, and the litter decomposition rate was Y1(10.30 a-1) > Y2 (9.60 a-1) >CK(6.41 a-1)>Y3(6.29 a-1)。 6. Whether the litter or soil qualities changed, the litter C element at the state of release at all times during the litter decomposition, and the release quantity increased with the decomposition rate augment. Litter released plentiful total penolics content during decomposition, and the release quantity had the positive correlation with the litter decomposition rate. The litter lignin content and the lignin/N all increased with the litter aqueous extracts concentration augment after litter decomposition.
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青藏高原东缘的亚高山针叶林是长江上游重要的生态屏障,经过近六十年的采伐后,取而代之的是大量人工种植的云杉纯林。目前,这些人工林已经表现出树种单一,结构层次简单等生态问题,其物种多样性及生态效益与同地带天然林相比差距较明显。如何丰富该地区物种多样性,完善人工林生态系统的生态功能是一个十分重要的课题。林下植物是人工林群落的重要组成部分,对维持群落的生物多样性及完善生态系统功能具有明显的作用。因此,研究该地区人工针叶林的林下植被对不同生境的适应性对于理解人工林生态系统物种多样性的形成和维持机制都具有重要的意义。 本文以青藏高原东部亚高山针叶林的主要森林类型----云杉人工林为研究对象,选择林下11种具有不同喜光特性的常见植物,分别设置人工林林冠下及成熟林窗为研究样地,通过对各种植物叶片形态与物质分配特征、叶片解剖学特征、叶片光合生理特性、植物自然分布特征等方面的比较分析,研究林下植物对不同光生境的适应策略及其适应能力,揭示不同物种对人工林生境的适应共性,为西南亚高山地区植被恢复及人工林的经营管理提供科学依据。具体研究结果如下: 在叶片形态和物质分配特征方面:在林窗光生境中,11种林下植物叶片比叶重(LMA)显著高于林下光生境的同种植物。同时,林窗下生长的植物叶片叶片厚度及栅栏细胞长度显著增加,这是影响叶片比叶重变化的直接原因。而多数植物叶重比在两种生境中无明显变化。说明在长期适应自然生境之后,植物可能更多地采取调节叶片组织细胞水平(即叶片功能细胞形态)及叶片器官水平(即单个叶片形态)特征的策略来适应各类生境,而非整株水平上的叶片总比重的增减。 在叶片解剖结构特征方面:多数阔叶物种栅栏组织厚度(PT)、栅栏组织厚度/海绵组织厚度(PT/ST)、栅栏细胞层数及近半数种的气孔密度(SD)在林窗生境中更大或更多,而叶片表皮细胞厚度(UET、LET)气孔长径(SL)及海绵组织厚度(ST)受两种生境影响不大。喜光特性相似的物种在生境适应策略上具有一定的趋同性。 在光合生理特征方面:在林窗生境中多数种植物的最大光合速率(Amax)、暗呼吸速率(Rd)及喜光植物光补偿点(LCP)显著或极显著高于林内生境同种植物。且在同一生境条件下,多数深度耐荫植物比喜光及轻度喜光植物有稍低的Rd和LCP。各植物在林内低光生境中具有更大的内禀光能转化效率,并在中午12:00~14:00之间光强最大的时刻发生了的最深程度的光抑制。多数种能通过调节自身某种光合素含量或色素之间的比例来适应不同的光生境,即通过增加叶绿素含量或降低Chla/b值来适应林内弱光生境,通过提高类胡萝卜素含量或单位叶绿素的类胡萝卜素含量降低强光带来的伤害。绝大多数物种并不采取调节叶片C、N含量的策略来适应不同的光生境。总之,植物部分光合参数(Amax、Rd、LCP)受生境的影响与其自身喜光特性有关,但另一些参数(Fv/Fm日变化、色素含量及比例、叶氮相对含量)受生境影响与其自身喜光特性无明显关联。 在表型可塑性方面:在叶片各表型参数中,器官水平及细胞水平的形态特征参数平均可塑性大于整株水平形态和物质分配特征参数可塑性;叶片光合组织的可塑性大于非光合组织可塑性;反映植物光合能力的参数可塑性大于叶片色素含量参数可塑性。植物叶片形态和物质分配、解剖学特征参数平均可塑性大小与其自身喜光特性基本吻合,即喜光种及轻度耐荫种各参数可塑性最高,深度耐荫种可塑性最小,而这种规律并未在光合生理参数的可塑性大小上体现出来。但是叶片形态和物质分配参数、光合生理参数的平均可塑性水平却大于叶片解剖学参数。 在植物自然分布特征方面:喜光物种云杉幼苗及歪头菜在林内生境中分布密度明显降低,深度耐荫种疏花槭却恰恰相反,更多数物种(7种植物)在两种生境中密度变化趋势不明显。从分布格局来看,7种植物在两种生境中均为聚集分布,但聚集强度为林窗>林内;少数物种桦叶荚迷、直穗小檗、冰川茶藨、黄背勾儿茶在林窗中为聚集型,在林内生境中的分布型发生改变而成为随机型,说明光生境的差异能影响到植物种群的分布特征。但这种影响程度与植物自身的喜光特性无关,同时与各物种叶片表型平均可塑性的大小也无明显关联。 The subalpine coniferous forest area in eastern Qinghai-Tibet Plateau is important ecology-barrier of upriver Yangtze. In past sixty years, those forests had been cut down and replaced with a lot of spruce plantations. At now, there are many ecology problems presenting to us such as singleness species, simple configuration, lower species diversity and ecological benefit than natural forests at the same belt. How to restore the species diversity and enhance the eco-function of the plantations is a very important issue. The understory plants are important part of plantation community, which improved the bio-diversity and eco-function distinctly of forests. So, it is very significance to study the adaptation of understory plants to different environment in plantation, and this study would helping us to understand how plantations to develop and remain their biodiversity. This study was conducted in a 60a spruce plantation in Miyaluo located in western Sichuan, China, and spruce plantation is major types of subalpine coniferous forest in eastern Qinghai-Tibet Plateau. In this paper, the leaf morphological and biomass-distributed characteristics, the anatomical characteristics, the photosynthetic characteristics and the distribution patterns characteristics of eleven different light-requirement understory species grown in two different environments (forest gaps and underneath close canopy) were studied and compared. The purpose of this study was to analyze the adaptation of this forest understory plants, to show up the commonness of these different light-requirement understory species in light acclimation, and to provide some scientific reference to manage and restore the vegetation of subalpine plantation of southwest China. The results were as follows: The leaf morphological and biomass-distributed characteristics: These eleven species in forest gaps had significantly higher dry weight per leaf area (LMA) than those under close canopy. The palisade parenchyma cells of the broad-leaved species in gaps were significantly longer than those grown under the canopy, which been a directed factor for the change of leaf mass per unit area (LMA) in different environment. But the leaf weight ratio (LWR) of most plants species were not evidently changed by the contrasted environments in our study. It was shown the morphological characteristics changing been adopted as a strategy of light acclimation for plants wasn’t on whole plant level (leaf weight ratio) but cellular level (the function cells morphological characteristics) and organic level (the leaf morphological and biomass-distributed characteristics) mostly. The leaf anatomical characteristics: Most broad-leaved plants in gaps increased palisade parenchyma thickness (PT), the palisade parenchyma cell layers and the ratio of palisade to spongy parenchyma (PT/ST). So did as almost about half species in this study in stomatal density (SD). No significant differences in thickness of leaf epidermal cells (UET, LET), stomatal length (SL) and spongy parenchyma (ST) between two environments of most species were observed. The results suggested that species with light-requirement approximately had convergent evolution on adaptation to light condition. The leaf photosynthetic characteristics: The dark respiration rate (Rd) of most plants species, the light compensation point (LCP) of light-demanding plants species in gaps were significantly increased than under close canopy in this study. In a same habitat, most deep-shade-tolerant plants had lower Rd and LCP than those light-demanding plants and slight-shade-tolerant plants. Each species has bigger inherent electron transport rate under close canopy than in gaps, and the greatest photoinhibition happened during 12 to 14 in the daytime. Most species could adapt different light environment by the way of changing their photosynthetic pigments content or the ratio of pigments content. For example, some plants under close canopy increased chlorophyll (Chl) or reduced the values of the ratio Chla/b to adapted the low light condition, some plants in gaps increased carotenoid (Car) or reduced the weight ratio CarChl to avoid been hurt in high light. For most plants, changing the content of C and N in leaf wasn’t a strategy of light acclimation. In conclusion, the variation of some leaf photosynthetic parameters in different light environment such as Fv/Fm, pigments, C and N in leaf related with the light-requirmnet of species, but the others such as Amax, Rd, LCP did not. The leaf plasticity indexes: Among those leaf plasticity indexes, the leaf morphological and biomass-distributed parameters on cellular and organic level were greater than on whole plant level for same species, and the photosynthetic parenchyma parameters were greater than non-photosynthetic parenchyma parameters in same leaf, and photosynthetic capability parameters were greater than photosynthetic pigments content parameters for same species. The average plasticity indexes of leaf morphological and biomass-distributed and anatomical parameters were accordant with plants’ light-requirement approximately: those light-demanding plants and slight-shade-tolerant plants had bigger plasticity indexes than deep-shade-tolerant plants. But this regular wasn’t observed in physiological plasticity indexes for most plants, though the average leaf plasticity indexes of leaf morphological and biomass-distributed, photosynthetic characteristics parameters was greater than the anatomical characteristics parameters. The distribution patterns characteristics: Oppositely to the deep-shade-tolerant specie Acer laxiflorum Pax., the density of light-demanding species Picea asperata Mast. and Vicia unijuga A. Br. in gaps was bigger than under close canopy. Each of the other species has the approximately density in two different environment. The spatial patterns of seven species were aggregated distribution in two environments, but the trend of aggregation of population under close canopy was decrease from in gaps. A few species such as Viburnum betulifoium Batal., Berberis dasystachya Maxim., Ribes glaciale Wall. and Berchemia flavescens Brongn. were aggregated distribution in gaps while random distribution under close canopy. It was shown that the difference between two light environments could affect the distribution pattern of plant population, and the effect didn’t relate with the light-requirement or plasticity indexes of species.