四川大头茶繁殖分配及其环境适应性的关联度研究

 本文研究了四川缙云山亚热带常绿阔叶林不同群落类型中四川大头茶的繁殖分配(RA),并将植物种群的繁殖提高到种群适应对策的高度来分析,探索了应用灰色关联度分析、灰色动态模型研究四川大头茶繁殖分配的环境适应性。结果表明四川大头茶的RA随群落类型、年龄而发生变化,其每年繁殖分配所占比例为13.6％～20.0％,不同群落类型中四川大头茶RA大小顺序为大头茶纯林>针阔叶混交林>常绿阔叶林。关联度分析指出,10个环境生态因子中对四川大头茶繁殖分配影响较大的环境因素是群落土壤pH值、群落内的热状况和肥、水条件。繁殖分配与环境因子间相互作用的灰色关联时间动态模型方程为dy/dt+0.42y＝0.07x1–4.26x2–6.38x3+15.54x4–7.46x5+4.72x6+1.97x7–0.66x8+0.57x9–0.20x10     

不同群落中四川大头茶 (Gordonia acuminata)花粉游离脯氨酸含量与种子产量

 四川大头茶(Gordonia acuminata)是缙云山亚热带常绿阔叶林的优势树种之一。对缙云山3种不同群落中四川大头茶的花粉游离脯氨酸含量和果实的种子产量进行了研究,发现花粉游离脯氨酸含量和每果种子产量在同一群落中的不同龄级四川大头茶个体间没有差异,但在不同群落间表现出差异。常绿阔叶林中的四川大头茶个体具有最高的花粉游离脯氨酸含量和每果种子产量,四川大头茶纯林中的次之,针阔混交林中的最低。分析发现,四川大头茶花粉游离脯氨酸含量与果实的种子产量有密切的正相关关系,花粉中的游离脯氨酸含量可以作为一种预测和比较相同地区不同生态环境中四川大头茶种子产量的指标。     

四川大头茶种群生殖生态学研究 Ⅱ.种群生物量生殖配置格局研究

在缙云山亚热带常绿阔叶林不同演替系列中,对四川大头茶乔木种群的生物量生殖配置格局及其影响因子进行系统研究,研究结果表明,四川大头茶种群不同生殖阶段的生物量生殖配置格局各异,同一生殖周期内,蕾花果期之ＲＡ值在不同演替系列分别为：常绿阔叶林４３．０３％,４０．７９Ｔ和４１．４５％,针阔混交林４．１３％,５．６２％和３５．５１％,四川大头茶纯林９．３２％,９．１２％和３１．６３％,四川大头茶种群的生殖周     

不同群落中四川大头茶（Gordonia acuminata）花粉游离脯氨酸含 …

四川大头茶（Ｇｏｒｄｏｎｉａ ａｃｕｍｉｎａｔａ）是缙云山亚热带常绿阔叶林的优势树种之一,对缙云山３种不同群落中四川大头茶的花粉游离脯氨酸含量和果实的种子产量进行了研究,发现花粉游离脯氨酸含量和每果种子产量在同一群落中的不同龄级四川大头茶个体间没有差异,但在不同群落间表现差异,常绿阔叶林中的四川大头茶个体具有最高的花粉游离脯氨酸含量和每果种子产量,四川大头茶纯林中的次之,针阔混交林中的最低。分析发     

四川大头茶在不同群落中的遗传分化及适合度成分

研究了四川大头茶在 3个群落中的遗传分化和适合度成分。 12个引物的 RAPD分析表明 ,仅有 10 %左右的遗传多样性存在于种群间。四川大头茶纯林结实率 (31.86 % )显著高于针阔混交林 (2 2 .5 3% )和常绿阔叶林 (2 4 .5 2 % )。每果种子数和每果种子均重各种群间差异均显著 ,每果种子数和每果种子均重分别为常绿阔叶林 (2 9.5 0 ,0 .0 15 4 g) ,四川大头茶纯林 (2 8.39,0 .0 172 g) ,针阔混交林 (2 7.4 4 ,0 .0 195 g) ,表明二者间存在着负耦联关系 (trade off)。而以 R =∑lxbx表示的适合度却以常绿阔叶林最大     

缙云山风灾迹地常绿阔叶林生态恢复过程中优势种群分布格局和动态

根据1992、1994、1996、1999和2001年对缙云山风灾迹地常绿阔叶林生态恢复的调查资料,对优势种群分布格局和动态进行了研究。结果表明：马尾松和大头茶的幼苗在恢复过程中不断减少,川灰木、小叶栲和其他常绿阔叶林树种的幼苗在增加;优势种群在不同大小级上分布格局不同,小叶栲和川灰木的I、Ⅱ、Ⅲ、Ⅳ级立木都呈聚集分布,大头茶的I、Ⅱ级苗木在1996年前呈聚集分布,1996年后呈随机分布,大头茶和马尾松的Ⅲ、Ⅳ级立木呈随机分布;马尾松和大头茶的年龄结构呈衰退型,川灰木和小叶栲的年龄结构呈增长型。     

重庆缙云山针阔混交林林隙树木更替规律研究

 研究了重庆缙云山大面积分布的亚热带次生性针阔混交林林隙树木更替规律,预测了该类型林林隙演替趋势。结果表明：马尾松(Pinus massoniana)种群表现出强烈的相互更替模式,四川大头茶(Gordonia acuminata)、四川山矾(Symplocos setchuanensis)等常绿阔叶树种自我更替与相互更替两种模式共存;林隙现实树木更替过程不能维持群落现有组成;Markov转移矩阵分析表明未来林冠层组成中马尾松种群将失去优势地位,整个群落将由针阔混交林向常绿阔叶林方向演替。     

鼎湖山植被演替过程优势种群动态研究Ⅲ．黄果厚壳桂和厚壳桂种群

森林群落的演替过程,是以各优势种群的动态为其表现特征．本项系列研究以系统地揭示鼎湖山森林植被演替过程各优势种群的动态为目的,本文研究了其中演替顶极种黄果厚壳桂和厚壳桂种群的动态．结果表明在演替过程中,其生态位宽度在针阔叶混交林阶段后期逐渐增大,这一趋势将至地带性中生性季风常绿阔叶林阶段．在这类中生性树种的发展过程中,种群的分布格局强度均有在高集群和随机分布之间、围绕低集群分布呈波动的趋势;其与早期先锋树种马尾松种群的生态位重叠值和种间联结值在针阔叶混交林阶段有较低值,至阳生性阔叶树种为优势常绿阔叶林阶段下降为零;而与阳生性树种的生态位重叠值和种间联结值由高向低转变,说明这类种群作为群落顶极种的特性．     

缙云山四川大茶种群繁殖适应性的数量特征研究

 在对缙云山3种含有四川大头茶种群的不同群落调查测定,研究四川大头茶种群年龄结构,繁殖分配,编制静态生命表的基础上,研编了四川大头茶种群的生殖力表,生殖表。对诸生殖参数进行了综合分析,剖析了构成四川大头茶繁殖对策的几个重要组成部分。结果表明：四川大头茶种群在常绿阔叶林中的繁殖寿命最长,适合度最大;四川大头茶种群的生殖值(Vx),现时生殖值(bx),剩余生殖值(RRV),累积剩余生殖值(SRRV)以及整个生活史的总生殖值(TRV)是时间的函数,并受环境制约,诸指标综合反映了遗传特性与环境因素相互作用对四川大头茶特定年龄个体繁殖能力影响的方式和强度,反映了四川大头茶种群繁殖动态规律;存活率lx与bx的负相关关系,SRRV与bx的负相关关系以及生命期望与生殖投资策略的负相关关系进一步反映了较大的生殖投入与较大的死亡概率之间的定量关系。     

不同邻体大头茶幼苗的适应特征

 在亚热带常绿阔叶林自然林窗下,以大头茶幼苗为基株,分别以马尾松、川灰木和大头茶幼苗为邻体。研究不同邻体如何改变可利用资源,影响大头茶幼苗基株生长动态和形态、树冠结构和生物量效应,并探讨影响基株生长的邻体的主导因素。结果表明,不同邻体的生长和截光效应差异明显;基株生长特征与邻体的树高、叶生物量、总生物量和树冠距地表10cm处截光量相关极小,却与邻体树冠距地表30cm处截光量相关极大,故影响基株生长的邻体主导因素是遮挡基株树冠的邻体的可利用光资源;基株生长动态,如树高、叶数、叶面积和叶大小,树冠结构和生物量显著受到不同邻体的影响,并且基株树高及增长量、叶面积、冠幅和生物量均为大头茶单株(GNO)>大头茶+川灰木(GNS)>大头茶+马尾松(GNP)>大头茶+大头茶(GNG)。大头茶幼苗种内竞争明显强于种间竞争。     

四种热带雨林树种光合和形态解剖特征对不同生长光强的适应

研究了西双版纳热带雨林2种喜光树种中平树(Macaranga denticulata)、倒樱木(Pnravallaris macrophylla)和2种耐荫树种云南肉豆蔻(Myristica yunnanensis)、金丝李(Garcinia paucinervis)幼苗叶片光合和形态解剖特征对3种不同生长光强(5％、25%和50％相对光强)的适应。研究结果表明,与强光下相比,弱光下生长的4种植物最大净光合速率、光饱和点、光补偿点、暗呼吸速率、叶绿素a／b、叶片和栅栏组织厚度、气孔密度和比叶重都降低,而海绵组织／栅栏组织和叶绿素含量升高。在相同光强下,与2种耐荫树种相比,2种喜光树种有较大的最大净光合速率、暗呼吸速率、气孔密度和较低的叶绿素含量。在不同光强下,4种植物均表现出了对光适应有利的生理和形态解剖可塑性,而喜光树种比耐荫树种有较大的生理和形态可塑性,表明喜光树种具有比耐荫树种对强光有更强的适应能力。4种植物的生理指标的可塑性均大于叶片解剖结构的可塑性。     

广东亚热带森林木本植物幼苗生长特性研究

研究了广东亚热带42种木本植物幼苗的生长及其与物种的生态特性、生活型、种子大小的相互关系.较强光下(H,66.8 μmol m-2s-1)乔木幼苗的茎高和茎生物量显著高于灌木幼苗的相应值,但在较低光下(L,33.7 μmol m-2s-1)两者无显著差异.而阳性植物、耐阴植物和中间型植物之间,茎高和茎生物量无显著差别.乔木幼苗的叶面积和叶生物量比灌木幼苗大,但灌木幼苗的叶片数较乔木幼苗多.大种子种和小种子种幼苗之间,阳性植物、耐阴植物和中间型植物幼苗之间的叶片数和叶面积一般无显著差异.阳性植物幼苗比耐阴植物幼苗侧根数多.乔木幼苗的根生物量和根/茎比显著高于灌木幼苗在较高光下,阳性植物幼苗的根/茎比较耐阴植物幼苗高,但在较低光下无明显差异.45 d幼苗的根生物量与种子重量呈显著的正相关,而90 d幼苗无明显的相关.乔木幼苗个体生物量显著高于灌木幼苗.幼苗相对生长率和叶面积比的大小呈现如下顺序阳性植物＞中间型植物＞耐阴植物,但只有阳性植物和耐阴植物之间有显著差异.阳性植物、中间型植物和耐阴植物幼苗之间的单位叶率无显著差异.     

Seedling growth strategies in Bauhinia species: comparing lianas and trees

BACKGROUND AND AIMS: Lianas are expected to differ from trees in their growth strategies. As a result these two groups of woody species will have different spatial distributions: lianas are more common in high light environments. This study determines the differences in growth patterns, biomass allocation and leaf traits in five closely related liana and tree species of the genus Bauhinia. METHODS: Seedlings of two light-demanding lianas (Bauhinia tenuiflora and B. claviflora), one shade-tolerant liana (B. aurea), and two light-demanding trees (B. purpurea and B. monandra) were grown in a shadehouse at 25% of full sunlight. A range of physiological, morphological and biomass parameters at the leaf and whole plant level were compared among these five species. KEY RESULTS: The two light-demanding liana species had higher relative growth rate (RGR), allocated more biomass to leaf production [higher leaf mass fraction (LMF) and higher leaf area ratio (LAR)] and stem mass fraction (SMF), and less biomass to the roots [root mass fraction (RMF)] than the two tree species. The shade-tolerant liana had the lowest RGR of all five species, and had a higher RMF, lower SMF and similar LMF than the two light-demanding liana species. The two light-demanding lianas had lower photosynthetic rates per unit area (A(area)) and similar photosynthetic rates per unit mass (A(mass)) than the trees. Across species, RGR was positively related to SLA, but not to LAR and A(area). CONCLUSIONS: It is concluded that the faster growth of light-demanding lianas compared with light-demanding trees is based on morphological parameters (SLA, LMF and LAR), and cannot be attributed to higher photosynthetic rates at the leaf level. The shade-tolerant liana exhibited a slow-growth strategy, compared with the light-demanding species.     

Phenotypic plasticity of lianas in response to altered light environment

The growth, morphology and biomass allocation of 11 liana species (six light-demanding and five shade-tolerant) were investigated by growing plants in three contrasting light environments (i.e., field, forest edge and forest interior). Our objectives were to determine: (1) changes in plant traits at the species level; and (2) differences in light-demanding and shade-tolerant species in response to altered light environment. We found that all seedlings of liana species increased in total biomass, total leaf area, relative growth rate (RGR), net assimilation rate (NAR), height, basal diameter, root length, leaf number, root mass/total plant mass (RMR) and root-to-shoot dry biomass (R/S ratio), and decreased in leaf area ratio (LAR), specific leaf area (SLA), leaf size, stem mass-to-total plant mass ratio (SMR) and leaf mass-to-total plant mass ratio (LMR) with increasing light availability. Under the three light environments, the two types of species differed significantly in total biomass, total leaf area, RGR, NAR, LAR, SLA and leaf number, and not in leaf area. Only light-demanding species differed significantly in height, root length, basal diameter, RMR, SMR, LMR and R/S ratio. The mean plasticity index of growth and biomass allocation were relatively higher than the morphological variables, with significant differences between the two groups. Our results showed that liana species respond differently to changing light environments and that light-demanding species exhibit higher plasticity. Such differences may affect the relative success of liana species in forest dynamics.     

四种热带雨林树种幼苗比叶重,光合特性和暗呼吸对生长光环境的适应

雾凉季研究了西双版纳热带雨林4种植物幼苗对生长光环境的适应,其中两个树种幼苗喜光（团花和滇南插柚紫）,两个树种幼苗耐荫（滇南红厚壳和玉蕊）发现弱光环境中生长的4种植物比叶重、光合能力、光饱和点、光补偿点暗呼吸速度、叶绿素a/b比较低,叶绿素含量较高。玉蕊和滇南红厚壳幼苗的光合能力和呼吸速度 于团花树和滇南插柚紫。团花树和滇南插机紫的比叶重和光合作用的可塑性大于玉蕊和滇南红厚壳。高光强下生长的团花树和滇南插机紫增加叶氮分配给羧化酶的比较。减少分配给叶绿素的比例。滇南红厚壳和玉蕊适应弱光环境的能力略强于团花树和滇南插机紫,但适应强光的能力较差。研究结果支持树种的生理生态特性决定了其演替状况和生境选择的假说,单位干重叶的光合能力和呼吸速率并未表现出利于光适应的可塑性,表明4种植物生理适应能力较差,形态学上的适应在4种热带雨林树种幼苗光适应方面起到了重要的作用,叶氮分配也是它们光适应的策略之一。     

Photosynthetic Characteristics,Dark Respiration,and Leaf Mass Per Unit Area in Seedlings of Four Tropical Tree Species Grown Under Three Irradiances

We investigated the effect of growth irradiance (I) on photon-saturated photosynthetic rate (P _max), dark respiration rate (R _D), carboxylation efficiency (CE), and leaf mass per unit area (LMA) in seedlings of the following four tropical tree species with contrasting shade-tolerance. Anthocephalus chinensis (Rubiaceae) and Linociera insignis (Oleaceae) are light-demanding, Barringtonia macrostachya (Lecythidaceae) and Calophyllum polyanthum (Clusiaceae) are shade-tolerant. Their seedlings were pot-planted under shading nets with 8, 25, and 50 % daylight for five months. With increase of I, all species displayed the trends of increases of LMA, photosynthetic saturation irradiance, and chlorophyll-based P _max, and decreases of chlorophyll (Chl) content on both area and mass bases, and mass-based P _max, R _D, and CE. The area-based P _max and CE increased with I for the light-demanders only. Three of the four species significantly increased Chl-based CE with I. This indicated the increase of nitrogen (N) allocation to carboxylation enzyme relative to Chl with I. Compared to the two shade-tolerants, under the same I, the two light-demanders had greater area- and Chl-based P _max, photosynthetic saturation irradiance, lower Chl content per unit area, and greater plasticity in LMA and area- or Chl-based P _max. Our results support the hypothesis that light-demanding species is more plastic in leaf morphology and physiology than shade-tolerant species, and acclimation to I of tropical seedlings is more associated with leaf morphological adjustment relative to physiology. Leaf nitrogen partitioning between photosynthetic enzymes and Chl also play a role in the acclimation to I.     

Seasonal Direct Light Availability Affects Mean Leaf Orientation in a Herbaceous Multi-Species Canopy

Abstract: Relationship between leaf orientation in natural or semi-natural herbaceous communities and the local abundance of direct light has rarely been investigated. We present evidence from a permanent plot experiment that seasonal direct light availability in 40 × 40 cm plots significantly affects mean leaf orientation in a semi-natural wooded meadow. In sunny years and in well-illuminated conditions, the leaf surface is exposed predominantly to the north, and vice versa . Two groups of species are responsible for such a response: of the variation in leaf orientation, 41 % is explainable through direct light availability for light-demanding species, and 26 % for graminoid species. In shade-tolerant species and in forbs there is no sign of a regression between leaf orientation and direct light abundance. Ability to plastically react to variation in seasonal and local direct light availability appears to be a trait under considerable selective pressure only in light-demanding plants, and more characteristic of species with graminoid growth form.     

林隙对香樟和枫香幼苗早期生长阶段功能性状的影响

探究林隙对不同需光性树种早期生长特征和功能性状的影响,对揭示林隙微生境影响次生林内幼苗更新机制具有重要意义。以亚热带次生林中耐荫常绿树种香樟和阳性落叶树种枫香幼苗为试验对象,研究大林隙(D/H介于1.5—2.0)、中林隙(D/H介于1.0—1.5)和小林隙(D/H介于0.5—1.0)对不同需光树种幼苗早期(1—3年生)生长特征和功能性状的影响。结果表明：(1)林隙大小对两种幼苗的生长均有显著影响。其中,中林隙可显著促进香樟2—3年生幼苗的生长,大林隙对枫香1—3年生幼苗的生长均具有显著促进作用。(2)对林隙环境因子与幼苗功能性状的关系进行冗余分析表明,香樟幼苗功能性状的变化与林隙土壤有机质含量、水解性氮含量、酸碱度和有效磷含量密切相关,而枫香幼苗功能性状则主要受林隙土壤酸碱度、有机质含量、水解性氮含量、土壤含水率、冠层透光率和土壤有效磷含量的影响。(3)维持较高的根重比、细根比根长、叶碳氮比和叶碳磷比是幼苗应对林隙环境影响的重要生理生态调节机制。     

Insects and light interact to mediate vine colonization of fast growing Microberlinia bisulcata tree seedlings in gaps of an African rain forest

Vines thrive in lowland tropical forests, yet the biotic factors underlying their colonization of host tree seedlings and saplings remain surprisingly understudied. Insect herbivores presumably could influence this process, especially where disturbance has opened the canopy (i.e., gaps)—temporary areas of higher primary productivity favoring the recruitment of vines and trees and invertebrates in forests—but their impact on vine colonization has never been experimentally tested. Using data from an insect herbivore exclusion (mesh-netting cages) experiment conducted in an African rain forest (Korup, Cameroon), I logistically modeled the probability of vines colonizing seedlings of three co-dominant species (Microberlinia bisulcata vs. Tetraberlinia bifoliolata and T. korupensis) in paired shaded understory and sunny gap locations (41 blocks across 80 ha, starting n = 664 seedlings) in a 1–2-yr period (2008–2009). Vine colonization occurred almost exclusively in gaps, occurring on 16% of seedlings there. Excluding herbivores in gaps doubled colonization of the light-demanding and faster growing M. bisulcata but had negligible effects on the two shade-tolerant, slower growing and less palatable Tetraberlinia species, which together were twice as susceptible to vines under natural forest gap conditions (controls). When protected from herbivores in gaps, more light to individual seedlings strongly increased vine colonization of M. bisulcata whereas its well-lit control individuals supported significantly fewer vines. These results suggest vines preferably colonize taller seedlings, and because light-demanding tree species grow faster in height with more light, they are more prone to being colonized in gaps; however, insect herbivores can mediate this process by stunting fast growing individuals so that colonization rates becomes more similar between co-occurring slow and fast growing tree species. Further influencing this process might be associational resistance or susceptibility to herbivores linked to host species’ leaf traits conferring shade-tolerant ability as seedlings or saplings. A richer understanding of how vines differentially influence forest regeneration and species composition may come from investigating vine–tree–herbivore interactions across light gradients, ideally via long-term studies and intercontinental comparisons. Abstract in French is available with online material.     

Growth dynamics of root and shoot hydraulic conductance in seedlings of five neotropical tree species: scaling to show possible adaptation to differing light regimes

The dynamics of growth (shoot and root dry weights, surface areas, hydraulic conductances, and root length) were measured in seedlings of five neotropical tree species aged 4–16 months. The species studied included two light-demanding pioneers (Miconia argentea and Apeiba membranacea) and three shade-tolerant young- or old-forest species (Pouteria reticulata, Gustavia superba, and Trichilia tuberculata). Growth analysis revealed that shoot and root dry weights and hydraulic conductances and leaf area all increased exponentially with time. Alternative methods of scaling measured parameters to reveal differences that might explain adaptations to microsites are discussed. Scaling root conductance to root surface area or root length revealed a few species differences but nothing that correlated with adaptation to light regimes. Scaling of root surface area or root length to root dry weight revealed that pioneers produced significantly more root area and length per gram dry weight investment than shade-tolerant species. Scaling of root and shoot hydraulic conductances to leaf area and scaling of root conductance to root dry weight and shoot conductance to shoot dry weight also revealed that pioneers were significantly more conductive to water than shade-tolerant species. The advantages of scaling hydraulic parameters to leaf surface area are discussed in terms of the Ohm's law analogue of water flow in plants. Received: 24 March 1997 / Accepted: 17 November 1997