光照对苦瓜形态可塑性及生物量配置的影响

在人为遮阴条件下,对苦瓜的生长动态、形态特征以及生物量分配进行了研究。结果表明,不同遮阴处理下苦瓜植株的生长有较大的差异,弱光照不利于苦瓜构件数量的增加和生物量的积累;植株在弱光下形成较少的分枝,较薄的叶片以及较细长的主茎和叶柄,表现出较强光生长环境下更强的形态可塑性;植株在生长早期较生长晚期有较大的形态可塑性;生物量对叶片和主茎的分配随光照的减弱而增大,分枝的生物量分配随光照的减弱而降低,光照对分枝茎的生物量分配影响不大;在光资源充足的情况下,外界支持物的缺乏不会对苦瓜的生长造成太大的影响。     

遮阴和磷限制下胡桃楸1级根养分吸收策略选择

本研究探讨了1年生胡桃楸在不同光照环境和不同剂量磷肥下根系功能性状的变化，以了解胡桃楸根系资源获取策略与光环境和磷养分限制之间的关系。设置了4种遮阴处理(全光、65%全光、35%全光和20%全光),以及3种磷肥处理(对照、200%和500%土壤本底有效磷),并测定了1级根形态、构型特征和菌根侵染率的变化。结果表明：随着遮阴程度的增加，胡桃楸1级根的平均直径、平均根长和菌根侵染率逐渐减小，比根长、比表面积、分支比和分支强度则呈现先增加后减小的趋势。随着磷含量的减少，1级根直径逐渐变细，而菌根侵染率则逐渐升高。在遮阴环境下，胡桃楸的根系形态和构型会发生适应性变化，通过增加比根长、比表面积、分支比和分支强度等来适应遮阴环境；而在磷限制条件下，胡桃楸的根系更倾向于与菌根真菌共生以促进对磷的吸收。胡桃楸在透光度为35%的林地人工更新时，根系形态、构型会做出改变以适应遮阴环境；在磷受限的情况下，胡桃楸与菌根真菌共生能力增强，可以适当接种菌根来帮助根系吸收磷。     

光照对珙桐幼苗光合与生长特性的影响

为了解珙桐幼苗对光强的适应性, 以3 年生珙桐幼苗为实验材料, 设置了全光照, 62%全光照及43%全光照3种光环境, 观测了110 d 后珙桐幼苗光合特性及生物量分配的变化情况。结果表明: (1)珙桐幼苗净光合速率(Pn)日变化在全光照条件下呈双峰型, 有明显“光合午休”现象, 而遮阴条件下呈单峰型; (2)遮阴处理下最大光合速率(Pmax)、表观量子效率(AQY)、水分利用效率(WUE)及光能利用效率(LUE)均高于全光照, 光补偿点(LCP)和暗呼吸速率(Rd)均低于全光照; (3)遮阴显著降低珙桐幼苗根冠比, 增加了比叶面积(SLA)和总生物量。上述结果说明: 遮阴处理后, 珙桐幼苗在光合特性和生长特性上表现出对弱光一定程度的驯化适应, 对比三种遮阴条件可以得知, 适度的遮阴更有利于幼苗的正常生长, 甚至在较低光照(43%全光照)环境下有更高的光能利用率。     

明党参幼苗存活与生长对光照强度的响应

以濒危植物明党参低温催芽形成的幼苗和常温正常萌发的幼苗为对象,对其存活及形态、结构、生物量及其分配、生长速率等指标进行测定和分析.结果表明,明党参幼苗在较高光强（65％全光照）存活率最高,有利于幼苗建成,低光强存活率最低.低温催芽形成的幼苗和常温正常萌发的幼苗对光照强度的响应规律类似,明党参幼苗的生长参数（株高除外）叶生物量、根生物量、总生物量、生长速率和总叶面积均在65％全光照条件下达到最大值,表现出最佳生长状况,表明适宜明党参幼苗生长的光照条件是65％全光照;利用低温催芽形成的幼苗生物量约是常温正常萌发幼苗的5倍,能提高其经受不利环境的能力,为明党参的栽培和保护提供一种新的途径.     

光强因子对少花桂幼苗形态和生理指标及精油含量的影响

光是影响植物生长的重要因子之一。它不仅能够影响植物的光合作用,同时,光还以环境信号的形式作用于植物,通过光敏色素等作用途径调节植物生长、发育和形态建成,使植物更好地适应外界环境。除此之外,光还可以影响植物的初生代谢过程和次生代谢。因此提高植物体内重要次生代谢产物,光的因素不可忽视。少花桂(Cinnamomum pauciflorum)是樟科樟属多年生常绿小乔木,其体内含有精油,鲜叶含油量可达3．5％,比黄樟树根含油量高出1倍左右,精油中黄樟油素纯度高达95％以上。以少花桂为材料,采用人工模拟不同生境的光照条件,探讨光强因子对少花桂生长及精油含量的影响,以求对其生产提供理论指导。通过窗纱遮荫实现对其生境光的控制,研究了光强因子对少花桂幼苗形态结构、水分状况、光合指标、生物量、香桂油含量和纯度的影响。结果表明：随生境相对光照强度的减弱,叶片厚度、叶片上表皮厚度、下表皮厚度、栅栏组织、海绵组织厚度、根冠比等都呈现降低的趋势;而平均单叶面积却呈现出增加的趋势;株叶面积在61．5％的全光照下有所增加,而在33．8％和15．4％全光照条件下大幅度减小;遮荫条件下生长的少花桂幼苗根系相对不发达,根冠比小;生境的光照强度会影响植株的水分蒸腾,从而影响含水量。在同样光照下,全光照条件下生长的少花桂幼苗保水能力最强,其次是61．5％全光照,最差的是15．4％全光照。少花桂幼苗的光饱和点、光补偿点随生境中的光强减弱而降低。过度遮荫条件下生长的少花桂幼苗CO2补偿点明显高于自然条件下生长的少花桂幼苗;随生境中的光强度的减弱其光呼吸速率升高,单位叶面积的叶绿素含量增加．Chla／Chlb值减小。遮荫处理后,不同光照条件下生长的少花桂幼苗的质量增加存在显著差异。遮荫过程中61．5％、33．8％和15．4％全光照条件下生长的少花桂幼苗叶片鲜质量的增长速率分别为全光照的1．6倍、1．2倍和0．77倍。香桂油含量以61．5％和33．8％全光照为多,均比全光照高出5％左右,而15．4％全光照叶片含油量又较全光照少5％左右。香桂油中黄樟油素纯度,以33．8％、15．4％全光照生境下的少花桂幼苗叶片为高。少花桂幼苗轻微遮荫(61．5％全光照)栽培．能获得较高的枝叶产量和香桂油产率．重度遮荫(33．8％、15．4％全光照)能获得纯度较高的黄樟油素。     

光照条件对蒙古栎幼苗生长特性和光合特征的影响

为了研究不同光照条件下蒙古栎幼苗的生长过程,本文通过控制实验,模拟设计4种不同的光照条件:全光照(FS)、轻度遮荫(LS)、中度遮荫(MS)和重度遮荫(SS),对蒙古栎幼苗的形态特征、光合特性和生物量分配进行比较研究。结果表明:中度遮荫和重度遮荫条件下蒙古栎幼苗的比叶面积显著大于全光照和轻度遮荫,不同光照条件下苗高无显著差异,全光照条件下蒙古栎幼苗的地径显著大于中度遮荫和重度遮荫,同时,全光照条件下的主根长度和根径显著大于3种遮荫条件,而轻度遮荫和中度遮荫又显著大于重度遮荫;最大净光合速率表现为轻度遮荫全光照中度遮荫重度遮荫的趋势,表观量子效率在全光照与轻度遮荫时显著大于中度遮荫和重度遮荫,暗呼吸速率无显著差异;全光照下单株总生物量和根系生物量最高,轻度遮荫和中度遮荫次之,重度遮荫最低;叶片生物量和茎生物量差异较小;不同器官生物量分配表现为根叶茎,并且根生物量所占比重在68%~76%之前;全光照、轻度遮荫和中度遮荫的根冠比显著高于重度遮荫。     

遮阴对地枫皮幼苗生长和生物量分配的影响

为了解光照强度对地枫皮(Illicium difengpi)幼苗生长和生物量分配的影响,对不同等级幼苗在不同遮阴处理下的形态和生物量变化进行了研究。结果表明,遮阴处理下幼苗的株高、冠宽和平均单叶面积均显著高于对照,同时比叶面积均随光强增大而显著降低。除I级苗50%遮阴处理外,全光处理下各等级幼苗的根长均显著高于遮阴处理。随着光照强度的增加,各等级幼苗的根生物量比与根冠比显著增加,叶生物量比显著减少;不同等级幼苗对强光和弱光环境均表现出较强的适应性,但以50%遮阴处理的总生物量最大,全光和85%遮阴处理均较小。遮阴处理的幼苗个体大小与其初始大小呈正相关,其中II级苗与I级苗差别较小,III级苗生长较差。在人工育苗条件下I级苗数量不到10%,较差的种苗质量叠加喀斯特山顶恶劣环境,可能是导致野外幼苗更新限制的重要原因。因此在野外回归和人工栽培过程中宜选用I、II级种苗,光强控制在透光率50%为宜。     

光照条件对蒙古栎幼苗生长及形态特征的影响

对生长于不同光照环境(林内和林外)下的蒙古栎幼苗的形态特征进行了比较.结果表明,光照条件对蒙古栎幼苗的生物量及其分配具有明显影响,林外幼苗单株生物量为林外的4.48倍,其中以根系生物量的差别为最大,林外为林内的6.23倍;林外与林内幼苗根冠比分别为2.70和1.11.在不同的光照条件下,蒙古栎幼苗的叶片形态表现出明显不同,林外叶片比叶面积明显低于林内,分别为139.55cm2/g 和284.94cm2/g,林内约为林外的2.04倍;一次生长叶面积林外明显低于林内,总叶面积则高于林内.二次生长使蒙古栎幼苗的叶面积有明显增加,但是经过二次生长后,幼苗的单株生物量没有明显增加,说明二次生长叶片对于蒙古栎幼苗生物量的积累没有明显贡献;光照对于蒙古栎主干及根系的形态具有明显影响,林外幼苗高(包括二次生长)明显低于林内幼苗,而地径则相反,林外幼苗根系的长度和直径则明显高于林内幼苗;林外幼苗顶芽体积明显大于林内幼苗.同时,林外幼苗的二次生长导致顶芽体积明显下降,从而对翌年的高生长量和未来干型产生影响.认为,蒙古栎幼苗通过形态上的一系列可塑性变化来适应不同的光环境以获取最大的碳收益.     

东北次生林主要树种比叶面积对光照强度的响应

通过测定不同光照条件下（15％透光、30％透光、60％透光、全光）东北次生林主要树种（红松、红皮云杉、胡桃楸、水曲柳和黄波罗）的比叶面积,探讨了不同树种对光照变化的响应与适应。结果表明:不同树种比叶面积存在明显的差异,尤其是常绿针叶树种与落叶树种之间差异显著（P<0.001）,指示不同功能型树种存在不同的生存策略;随着光照强度降低,所有树种比叶面积呈现增加的趋势,尤其是弱光照（15％）和低光照（30％）相对于全光和中光照（60％）差异显著（P<0.05）;不同树种比叶面积随光照强度的变化幅度明显不同,且变化最显著的光照区域也有所不同;不同年龄红松比叶面积的变化趋势一致,但变幅不同,4年生幼苗对光照响应则更为明显。本研究结果表明,所有树种均能通过改变叶形态来适应光照条件的变化,在低光条件下通过增加单位质量叶面积,提高叶片光捕获能力;但各树种对光照强度变化的不同响应则表明树种之间不同的光适应机制,这对森林生态系统内部树种的共生具有重要意义;年龄较小的幼苗对光照的强响应指示其在植物更新过程中叶片水平上生理生态学机理研究中的重要性。     

遮阴对石笔木苗木生长和保护酶活性的影响

为探讨石笔木Tutcheria championi苗木对遮阴环境的适应性,以全光照(无遮阴覆盖)为对照,研究遮阴30%、50%和70%对2年生石笔木苗生长和生理特性的影响。结果表明,全光照下石笔木苗木生长较为健壮,其苗高、地径生长优于遮阴处理;全光照下石笔木总生物量、根生物量比以及根冠比显著大于遮阴处理(P<0.05);50%遮阴处理苗木叶片叶绿素含量显著高于全光照和70%遮阴处理(P<0.05),叶绿素a/b值在各处理间无显著差异。丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性在各处理间无显著差异(P>0.05);70%遮阴处理的苗木叶片过氧化氢酶(CAT)活性最高,显著高于全光照和50%遮阴。由此表明,充足的光照环境有利于石笔木苗木生长。     

Biomass allocation, shade tolerance and seedling survival of the invasive species

Berberis darwinii (Berberidaceae) is a serious environmental weed in New Zealand, capable of invading a range of different light environments from grazed pasture to intact forest. According to optimal partitioning models, some plants optimise growth under different environmental conditions by shifting biomass allocation among tissue types (e.g. roots, shoots) to maximise the capture of limiting resources (e.g. water, light). We examined patterns of growth, biomass allocation, and seedling survival in Berberis darwinii to determine whether any of these factors might be contributing to invasion success. Growth and biomass allocation parameters were measured on seedlings grown for 7 months in five natural light environments in the field. Survival was high in the sunniest sites, and low in the shadiest sites. Seedlings grown in full sun were an order of magnitude taller and heavier, had five times as many leaves, and proportionally more biomass allocated to leaves than seedlings grown in other light environments. In the shade, leaves were bigger and thinner, and leaf area as a proportion of total plant biomass increased, but the proportion of above- to below-ground biomass was similar across all light and soil moisture environments. In summary, although leaf traits were plastic, patterns of biomass allocation did not vary according to optimal partitioning models, and were not correlated with patterns of seedling survival. Implications for the management of this invasive species are discussed.     

Seed germination and seedling growth in the arrow bamboo <Emphasis Type="Italic">Fargesia qinlingensis</Emphasis>

Improving natural regeneration of bamboos after they die following mass flowering is critical for conservation of giant pandas. However, little is known about factors that affect seed germination and seedling growth of bamboos. We studied seed germination and seedling growth in Fargesia qinlingensis, which mass flowered in a giant panda habitat in the Qinling Mountains of China in early 2000, in laboratory and greenhouse conditions. Seed germination rate was tested under light and dark conditions 5 and 12 months after seed collection. Germination rate displayed no significant difference under light or dark conditions 5 months after seed collection, but was significantly greater in the dark than under light 12 months after seed collection, suggesting light inhibition of seed germination. A 2×2 factorial design was conducted to test the effects of nitrogen (N fertilization and non-N fertilization) and light [full sun and shade (i.e., 14% full sun)] on seedling growth and biomass allocation. N fertilization significantly increased seedling growth, resulting in greater seedling height, more branches, more leaves, greater stem biomass, and greater leaf biomass. Seedlings under 14% full sun conditions had a significantly lower percentage of biomass allocated to the stem. The root/shoot ratio was significantly greater in non-N/shade than non-N/full sun, while there was no significant difference in this ratio between N/shade and N/full sun, suggesting that nitrogen fertilization compensated for the effect of shade on biomass allocation. Our results suggest that N fertilization could be employed in restoration of F. qinlingensis stands after die-off following mass flowering.     

Growth and leaf production in the tropical palm Euterpe edulis: Light conditions versus developmental constraints

We studied developmental and environmental constraints on leaf dynamics, morphology and physiology in the monopodial tropical palm of the Atlantic Forest biome, Euterpe edulis. Plastic responses to light environments in terms of photosynthesis, leaf size, leaf life span, patterns of biomass allocation and growth were analysed. Plants were grown during 14 months in a shade house under four different growth irradiances. Plants of Euterpe edulis were able to adjust leaf demography and biomass allocation in the different light treatments. Leaf life span increased by 100 days with decreasing light levels while the rate of leaf production decreased, consistent with lower electron transport rates. At low light levels, adjustments in biomass allocation to leaf components allowed E. edulis to reduce self-shading and increase light interception. At high light plants allocated more biomass to roots, and the plants exhibited small leaf sizes when leaves were compared using an explicit ontogenetic analysis. Ontogeny constrained the maximum size that each consecutive leaf could achieve, while growth irradiance determined the rate of leaf production and other leaf traits. Consequently, there were both, developmental constraints and environmental determinants influencing leaf demography and morphology in E. edulis. The findings of this ecophysiological and demographic study are relevant to palms growing under natural conditions and help to explain the success of E. edulis in the forest understory and its absence from large gap openings. Our results not only confirm that E. edulis is a shade tolerant species, but also show that palms are able to acclimate to different growing condition as well as trees.     

Plasticity in seedling morphology,biomass allocation and physiology among ten temperate tree species in response to shade is related to shade tolerance and not leaf habit

• Mechanisms of shade tolerance in tree seedlings, and thus growth in shade, may differ by leaf habit and vary with ontogeny following seed germination. To examine early responses of seedlings to shade in relation to morphological, physiological and biomass allocation traits, we compared seedlings of 10 temperate species, varying in their leaf habit (broadleaved versus needle‐leaved) and observed tolerance to shade, when growing in two contrasting light treatments – open (about 20% of full sunlight) and shade (about 5% of full sunlight).
• We analyzed biomass allocation and its response to shade using allometric relationships. We also measured leaf gas exchange rates and leaf N in the two light treatments.
• Compared to the open treatment, shading significantly increased traits typically associated with high relative growth rate (RGR) – leaf area ratio (LAR), specific leaf area (SLA), and allocation of biomass into leaves, and reduced seedling mass and allocation to roots, and net assimilation rate (NAR). Interestingly, RGR was not affected by light treatment, likely because of morphological and physiological adjustments in shaded plants that offset reductions of in situ net assimilation of carbon in shade. Leaf area‐based rates of light‐saturated leaf gas exchange differed among species groups, but not between light treatments, as leaf N concentration increased in concert with increased SLA in shade.
• We found little evidence to support the hypothesis of a increased plasticity of broadleaved species compared to needle‐leaved conifers in response to shade. However, an expectation of higher plasticity in shade‐intolerant species than in shade‐tolerant ones, and in leaf and plant morphology than in biomass allocation was supported across species of contrasting leaf habit.

     

遮荫对水曲柳和蒙古栎光合、生长和生物量分配的影响

为探讨水曲柳(Fraxinus mandshurica)和蒙古栎(Quercus mongolica)苗期对光的适应性及其生长最适光强,设置4种光环境(全光(FL)、75%光(LS)、50%光(MS)、25%光(HS)),观测了2年生水曲柳和蒙古栎苗木气体交换参数、叶绿素含量(Chl)和比叶重(LMA)、生长及生物量的分配。结果表明:随着光强的减弱,2个树种的LMA、单位叶鲜质量(LFA)和根冠比均呈下降趋势;叶绿素含量(Chl)呈上升趋势,且差异显著(p<0.05);光补偿点(LCP)和暗呼吸速率(Rd)呈"N"形变化,但差异均不显著(p>0.05);水曲柳的最大光合速率(Pmax)在HS处理下最大,Rd在HS处理下最小;蒙古栎的最大光合速率(Pmax)在LS处理下最大,Rd也较小;在全光处理下苗高增量均低于HS处理,地径增量均高于HS处理。研究结果进一步确定水曲柳苗期具有一定的耐荫性,在弱光强下生长较好;蒙古栎苗期对光照要求较高,在相对较强光照下生长较好。     

不同光环境对麻栎和刺槐幼苗生长和光合特征的影响

通过搭建遮阳棚设置3个光照强度,模拟森林幼苗生长的林缘、林窗和林下光环境,研究麻栎和刺槐幼苗形态结构、光合特性、生物量积累及其分配对不同光照强度的响应。结果表明,极度弱光环境限制了幼苗的株高、基径、总叶面积、冠面积、叶面积指数和总叶数等形态指标的增长,与全光环境相比,适度遮荫有利于幼苗的形态生长,光照对麻栎形态的异速生长曲线影响较小,刺槐较麻栎的曲线变化更明显一些,弱光降低了异速生长指数。随遮荫程度的增加,麻栎的净光合速率、蒸腾速率、气孔导度逐渐降低,刺槐的净光合速率则在适度遮荫下最大,两者的光能利用效率均显著增大,水分利用效率先升后降。随光照强度的减弱,麻栎各器官的生物量积累降低,叶面积比率的增加和根冠比的减少有利于增加光能的捕获,而刺槐的生物量积累和分配则在适度遮荫下达到最优;各叶绿素含量均显著上升,而叶绿素a/b则逐渐下降。麻栎和刺槐显示出不同的生存策略和光利用策略,在一定程度上可以揭示它们在阔叶林群落中不同的演替地位。     

Responses to Light and Water Availability of Four Invasive Melastomataceae in the Hawaiian Islands

Plant invasion by Neotropical Melastomataceae is prominent in Hawaii. To understand life history traits of four successful invasive Melastomataceae, two shade-intolerant herbs (Arthrostema ciliatum and Tibouchina herbacea) and two shade-tolerant woody species (Clidemia hirta, a shrub, and Miconia calvescens, a tree) were subjected to three light levels and two watering regimes in a greenhouse. Plant height, leaf number and area, biomass allocation, relative growth rate (RGR), carbon assimilation (A), leaf nutrient content, leaf construction costs (CC), specific leaf mass (SLM), and leaf spectral properties were determined at the end of the experimental period. Plant size, total biomass, RGR, A, CC, and SLM decreased, whereas leaf light transmittance and leaf N increased under low light in all species. The effects of water stress were weaker than light-stress effects. Relative growth rate of herbs grown in sun and partial shade (0.046 and 0.033 g g-1 d-1, respectively) was higher than in the woody species (0.027 and 0.020 g g-1 d-1). Woody species allocated more biomass to leaf production than herbs, which allocated more biomass to stem production. Shade increased allocation of biomass to leaves, and water stress increased the root-shoot ratio in all species. Partial shade increased leaf area ratios more in the herbs (140%) than in woody species (68%). Miconia calvescens and C. hirta had higher leaf absorbance (92%) than both herbs (79%). Maximum A under all light treatments was similar in all species, and there was substantial acclimation to the different light levels. Leaf construction cost was higher in the apparently long-lived leaves of the woody species. Relative growth rate, carbon allocation, and SLM showed larger changes to light and water stress than A and related photosynthetic parameters. All species showed responses qualitatively similar to those of other tropical species including the high acclimation potential to light, but the herbs exhibited the largest quantitative responses. When compared with a large group of native species, the four melastomes appear to be better suited to capture and use light, which is consistent with their rapid spread in mesic and disturbed Hawaiian environments.     

长白山阔叶红松林主要树种对干旱胁迫的生态反应及生物量分配的初步研究

以组成长白山温带阔叶红松林主要树种红松,水曲柳,胡桃楸,椴树和蒙古柞的幼苗,盆载于土壤含水量分别为田间持水量的85％－100％（CK）,65％－85％（MW）和45％－65％（LW）条件下4个月,研究不同土壤水分亏缺对不同树种生态反应和生物量再分配,结果表明,干旱处理显著降低供试树种的单叶面积,侧根数,根长等,降低叶比重,增加根比重,不同种对干旱响应应存在明显差异,椴树和水曲柳叶比重随水分亏缺的加剧而显著降低,蒙古柞和胡桃揪叶比重值在轻度水分亏缺时达到最高,但不同树种幼树茎比重并不随土壤水分含量的降低而发生明显变化,各树种生物量较对照组有显著差异,椴树,水曲柳,胡桃揪,红松幼树总生物量平均降低32．8,43．6,26．2和23．8％,蒙古柞幼 树生物量平均增加4．8％,耐旱性比其它4个供试树种强。     

Seedling morphological characteristics and seasonal growth of indigenous tree species transplanted into four plantations in South China

The successful transplantation of indigenous tree seedlings into established plantations requires an understanding of the conditions required by the seedlings. We evaluated seedling morphological characteristics and seasonal growth of three indigenous tree species (Castanopsis chinensis, Michelia chapensis, and Psychotria rubra) that were transplanted into four plantations (eucalyptus, mixed-native, mixed-legume, mixed-conifer) in South China; in each plantation, two treatments (understory vegetation and litter retained or removed) were applied before the seedlings were transplanted. Seedling leaf morphological characteristics and biomass allocation were determined at the end of the experiment, and seedling relative growth rate as indicated by change in height (RGRh) was determined during the experiment. Whether understory vegetation and litter were removed or retained, RGRh tended to be higher in the wet season than in the dry season. Leaf morphological characteristics and biomass allocation were significantly affected by species identity. The effect of the understory vegetation and litter treatments on seedling morphological characteristics such as specific leaf area, leaf area ratio, and root weight to total biomass ratio depended on species identity. Redundancy analysis showed that the three transplanted indigenous species differed in their responses to light conditions according to their tolerance to shade, and also differed in their responses to soil physical and chemical properties. Based on seedling seasonal growth patterns and morphological responses, we suggest that forest managers attempting to introduce seedlings of indigenous tree species should artificially supply water to increase seedling growth in the dry season. Also, the introduced tree species should be selected depending on the nature of the plantation; for example, C. chinensis and M. chapensis seedlings can be transplanted into mixed-legume plantations. Additionally, fertilizer with potassium and nitrogen should be used to improve seedling performance.     

伞形科两种植物幼苗生长对光照强度的可塑性响应

将明党参（Changium smyrnioides Wolff）和峨参（Anthriscus sylvestris Hoffm．）幼苗置于按全光照百分率为100％（S100）、65％（S65）和25％（S25）的人工控制光环境下处理。结果表明,光照强度显著影响明党参和峨参幼苗的生长：明党参在S6,生长最好,株高、冠幅、叶长、叶宽、地上地下生物量等均达到最大值,且S65的明党参生物量是S100的2倍、S25的3倍左右;而峨参地上部生长随着光照强度的减弱而增强,S25生长最好,但地下部生长则在S65生长最好,表现出与明党参同样的响应规律。明党参在不同光照强度下生长速率差异显著,S65显著高于其余两个处理;峨参虽然也在S65生长速率最大,但在不同光照强度间无差异。明党参生长速率明显小于峨参,总生物量约为峨参的1／3—1／8,相对于峨参而言明党参是一个在幼苗阶段生长缓慢的物种。