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。     

遮荫和氮养分对三裂叶蟛蜞菊生长、构件生物量分配和叶片PSⅡ功能的影响

为探查外来入侵植物三裂叶蟛蜞菊(Wedelia trilobata)对遮荫和氮养分的响应及其入侵性, 采用盆栽实验研究了遮荫(轻度遮荫-相对光强为42%; 重度遮荫-相对光强为12%)和不同氮养分(0、0.1、0.2 和0.4 g·kg^–1)对三裂叶蟛蜞菊生长、生物量分配以及叶片PSⅡ功能的影响。结果表明: 1)经轻度遮荫的植物叶片数、分枝数、总生物量、生长速率显著大于重度遮荫; 同一遮荫条件下, 随氮养分的增加, 茎生物量比增加、叶生物量比下降。2)重度遮荫降低了三裂叶蟛蜞菊叶片实际光化学效率(ФPSⅡ)和表观光合电子传递速率(ETR), 对叶片PSⅡ反应中心有一定破坏作用; 对最大光化学量子产量(Fv/Fm)的影响不显著(除0.2 g·kg^–1 氮水平外)。3)氮养分对叶片PSⅡ活性的影响随遮荫程度而变化,轻度遮荫下, 氮养分对叶片PSⅡ功能影响较小; 重度遮荫下, 随氮养分的增加, ФPSⅡ和ETR 先上升后下降, Fv/Fm 变化不显著。4)光强和氮养分的交互作用在三裂叶蟛蜞菊种群生长、竞争以及成功入侵过程中发挥着重要作用, 在光照较充足的生境中容易成功入侵。     

葡匐茎草本绢毛匐委陵菜对局部蔗荫的克隆可塑性

采自林窗和林内生境的绢毛匍匐委陵菜（Ｐｏｔｅｎｔｉｌｌａ ｒｅｐｔａｎｓ Ｌ．ｖａｒ．ｓｅｒｉｃｏｐｈｙｌｌａ Ｆｒａｎｃｈ）“分株对”（即由一匍匐茎节间相连着的两个分株,其一为“目标分株”,另一为“相连分株”）在一户外实验中经历了全不遮荫、全部遮荫和局部遮荫处理。该植物的基株生物量、匍匐茎总长度、分株数、葡匐茎比节间重、叶西风长、比叶柄重在遮荫条件下较小。葡匐茎节间长度没有对遮荫处理发生反应。     

不同分枝数对桑树幼苗生长发育的影响

以我国常见经济林木桑树(Morus alba)为试验材料,从气体交换、形态变化和地上生物量方面研究5种分枝模式(1、2、3、4和5枝)对幼苗生长发育的影响。结果显示:(1)分枝数为1的植株的净光合速率(P n)最高,达到8.6μmol·m-2·s-1。随着分枝数增加,P n显著下降,直至分枝数达到3枝及其以上时,净光合速率保持相对稳定,为4.3μmol·m-2·s-1。而气孔导度(g s)、胞间CO2浓度(C i)和蒸腾速率(E)则不受分枝数的影响。(2)随着分枝数增加,总叶片数量、总叶面积和总枝长都显著增加,最终分别达到114.3,10481.1 cm2和457.1 cm,而平均单枝叶片数、平均单枝基径、平均单叶面积和比叶面积则显著减少。(3)随着分枝数的增加,植株的总叶生物量和总枝生物量无显著变化,但平均每枝叶干重、平均每枝枝干重和平均每枝总生物量随分枝数的增加而逐渐减少。研究结果表明了分枝数增加可能导致叶片间对光资源的竞争强度增大,引起净光合速率下降,叶片面积变小,单枝长度和生物量减小。另一方面,植株则通过生长出更多的叶片数量,以及更大的总叶片面积来尽可能地消除竞争带来的不利影响,提高对光环境资源的利用。     

台湾相思林和芒草草丛中薇甘菊枝构件的分枝格局及其生物量

外域杂草薇甘菊 (Mikaniamicrantha)具有极强的分枝能力。在枝构件水平上 ,对生长在台湾相思 (Acaciaconfusa)群落和芒草 (Miscanthussinensis)群落中的薇甘菊枝构件的分枝格局和生物量分配的比较分析得出 :1)同芒草群落相比 ,台湾相思群落中薇甘菊各级枝的分枝数、分枝密度和分枝率都低 ,而分枝长度则较长 ;2 )台湾相思群落中薇甘菊以第一级分枝为主 ,而在芒草群落中则以第二级分枝为主 ;3)台湾相思林中薇甘菊枝构件的叶面积率、比叶面积和比茎长及叶片生物量分配显著大于芒草草丛 ;4)两个群落中薇甘菊枝构件的节间长和比叶柄长没有显著差异。这些结果说明薇甘菊枝构件对环境条件变化具不同响应。     

台湾相思林和芒草草丛中薇甘菊枝构件的分枝格局及其生物量

 外域杂草薇甘菊(Mikania micrantha)具有极强的分枝能力。在枝构件水平上,对生长在台湾相思(Acacia confusa)群落和芒草(Miscanthus sinensis)群落中的薇甘菊枝构件的分枝格局和生物量分配的比较分析得出：1）同芒草群落相比,台湾相思群落中薇甘菊各级枝的分枝数、分枝密度和分枝率都低,而分枝长度则较长;2）台湾相思群落中薇甘菊以第一级分枝为主,而在芒草群落中则以第二级分枝为主;3）台湾相思林中薇甘菊枝构件的叶面积率、比叶面积和比茎长及叶片生物量分配显著大于芒草草丛;4     

栓皮栎地上部分构型及生物量分配

研究秦岭南坡商洛地区不同径级栓皮栎的地上部分构型、生物量及其分配和构型与生物量的关系.结果表明： 不同径级栓皮栎地上部分构型与生物量的分配存在差异.随着径级的增大,栓皮栎树高、胸径和冠幅逐渐增大;平均递减率先增大后减小;栓皮栎总体分枝率和逐步分枝率先增加后下降;不同径级栓皮栎垂直方向上的比叶面积为0.02～0.03,叶重比、叶面积指数和叶面积比的较大值在径级为Ⅰ、Ⅱ、Ⅲ时出现于树干中、上部,在径级为Ⅳ、Ⅴ、Ⅵ时出现在树干中部,径级进一步增大则在垂直方向上出现2个峰值,分别位于树干中下部和中上部.栓皮栎地上部分生物量中,树干生物量占71.8%～88.4%,枝生物量占5.8%～19.6%,叶生物量占4.2%～8.6%.随着径级的增大,树干生物量所占比例先减小后增大,而枝、叶生物量所占比例呈先增大后减小再增大的趋势.栓皮栎地上部分生物量与树高、胸径、冠幅和逐步分枝率(R_2∶1)呈显著正相关,与总体分枝率和逐步分枝率(R_3∶2)呈正相关趋势,但相关性不显著.树干生物量、地上总生物量与树干递减率呈负相关趋势,枝生物量、叶生物量与树干递减率呈正相关趋势,但相关性均不显著.     

薰衣草枝叶性状关系的个体大小依赖

植物枝叶性状的个体大小差异,是植物适应异质性环境所形成的冠层构建策略,对于理解枝叶构建机制及光合生理代谢具有重要意义。于2017年7月下旬,在金水湖湿地公园选择一块薰衣草样地,根据体积将薰衣草(Lavandula angustifolia)分为3个大小等级[I级:植株体积的立方根(d)≤60 cm、II级(60 cmd≤90 cm)和III级(d90 cm)],采用一元线性回归方法,研究了薰衣草种群枝叶性状的个体大小依赖。结果表明:随着薰衣草植株大小等级增大,薰衣草的叶面积、枝长度、枝数量和枝横截面积逐渐增大,而叶数量、叶厚度和分枝角度逐渐减小。薰衣草叶面积、枝长度和枝数量与个体大小呈极显著的正相关(P0.01),枝横截面积与个体大小呈显著的正相关(P0.05),叶数量和叶厚度与个体大小呈极显著的负相关(P0.01),分枝角度与个体大小呈显著的负相关(P0.01)。为提高资源利用效率,大个体薰衣草选择生长少量大而薄的叶片以及分配更多的生物量用于小枝的生长;而小个体薰衣草选择生长多数小而厚的叶片以及短而细的枝条,体现了不同大小等级薰衣草枝叶表型可塑性。     

匍匐茎草本绢毛匍匐委陵菜对局部遮荫的克隆可塑性

采自林窗和林内生境的绢毛匍匐委陵菜 (PotentillareptansL .var.sericophyllaFranch)“分株对”(即由一匍匐茎节间相连着的两个分株 ,其一为“目标分株” ,另一为“相连分株”)在一户外实验中经历了全不遮荫、全部遮荫和局部遮荫处理。该植物的基株生物量、匍匐茎总长度、分株数、匍匐茎比节间重、叶柄长、比叶柄重在遮荫条件下较小。匍匐茎节间长度没有对遮荫处理发生反应。在局部遮荫处理 ,遮荫斑块的分株的叶柄长度由于连着未遮荫斑块中分株而变得更长。这种克隆整合对克隆形态可塑性的修饰作用只在林窗生境来源的实验植物中观察到。其他克隆生长和克隆形态特征的可塑性在不同生境来源的实验植物间没有差异。     

江西常绿阔叶林木本植物不同冠层高度当年生小枝茎构型对叶生物量的影响

以江西阳际峰自然保区69种木本植物为对象,采用标准化主轴回归(SMA)的方法,对不同冠层高度当年生小枝的构件生物量(叶生物量、茎生物量、小枝生物量)与茎构型特征(茎直径、茎长度、茎宽长比、茎体积和茎密度)进行了分析,研究当年生小枝茎构型对叶生物量的影响.结果表明:不同冠层高度及生活型间叶生物量、茎生物量、小枝生物量、茎直径、茎长度、茎宽长比及茎体积均无显著差异,而茎密度差异显著.不同冠层高度及生活型间,叶生物量与茎生物量及总生物量之间均呈显著等速生长关系.小枝叶生物量分别与茎直径、茎体积呈显著异速生长关系,且该异速生长指数在不同冠层高度无显著差异.茎长度、茎宽长比及茎密度对当年生小枝叶生物量变异的解释力较小(<24%).冠层高度和生活型对小枝叶-茎生物量的等速分配关系影响不显著.小枝茎构型中,相比于茎长度、茎宽长比以及茎密度,茎的直径与体积对当年生小枝叶生物量的影响更大,冠层高度对当年生小枝茎构型与叶生物量间的异速分配模式无显著影响.     

Clonal Plasticity in Response to Partial Neutral Shading in the Stoloniferous Herb Potentilla reptans var. sericophylla

Ramet-pairs of Potentilla reptans L. var.sericophylla Franch from forest gap and forest understory were subjected to unshading, shading and partial shading treatments in a pot experiment. The genet biomass, total length of stolons, number of ramets, specific stolon weight, petiole length and specific petiole weight of the plant species under the shaded condition were smaller than those under the unshaded condition. The stolon internode length did not respond to the various treatments. In the plants from the forest gap, the petiloes of ramet grown in the shaded patch were longer as connected to plant part in the unshaded patch than as connected to plant part under the same shaded condition. Such modification of local response of ramet petiole to shading due to physiological integration was not observed in the plants from the understory. There was no effect of connection to ramets in shaded patches on the local response of the rest ramet characters to the partial unshading.     

Physiological acclimation and growth response to partial shading in <Emphasis Type="Italic">Salix matsudana</Emphasis> in the Mu Us Sandland in China

In a controlled experiment, Salix matsudana plants were subjected to uniform nonshading (F-S), partial shading (P-S) and uniform shading (U-S). The shoots of the plants in the F-S and U-S treatments were referred to as H-H and L-L, respectively. The plants in the P-S treatment had two kinds of shoots: (1) shoots under the nonshading treatment that were connected to others under the shading treatment (H-L).(2) Shoots under the shading treatment that were connected to others under the nonshading treatment (L-H). The physiological acclimation and growth response of the species to the partial shading were examined. The partial shading had significant effects on photosynthetic dynamics, transpiration and stomatal conductance, but no effect on instantaneous water use efficiency and maximum quantum yield. Water saturation deficit and coefficient of water loss were significantly smaller in the H-L shoots than in the H-H shoots. Leaf natality, leaf mortality and leaf turnover were greater in the H-L shoots than in the H-H shoots. In contrast, these three parameters were smaller in the L-H shoots than in the L-L shoots. The H-L shoots had significantly larger branching ratio, total branch length and shoot biomass than the H-H shoots. The L-H shoots had smaller branching ratio, total branch length and shoot biomass than the L-L shoots. Total plant biomass in the treatments increased as follows: F-S相似文献   

Effects of host shading on consumption and growth of the geometrid Epirrita autumnata: interactive roles of water, primary and secondary compounds

Shading is assumed to reduce allocation to plant phenolics and to defense in general. We here report the results of experimental shading of individual branches or whole canopies in mountain birch on foliar chemistry and on the growth and consumption of a geometrid, Epirritaautumnata. Branch‐wide shading tended to have at least as strong effects on both leaf chemistry and herbivore performance as canopy‐wide shading, indicating local responses of the host to shading. Responses to shading varied among the key leaf traits. Leaf water content was higher and toughness lower in shaded than in non‐shaded leaves. Leaf sugars were lower and protein‐bound and free amino acids higher in shaded than in control leaves. Sucrose and galactose were at high levels in unshaded branches adjacent to shaded ones, suggesting that partial shading enhanced translocation of sugars within canopies. Total phenolics and soluble proanthocyanidins were low in both shading treatments. Of the other phenolic groups, concentrations of gallotannins and cell‐wall‐bound proanthocyanidins did not differ between shaded and non‐shaded leaves. Epirrita larvae grew better in both types of shading treatments compared to either unshaded control trees or to unshaded branches in the branch‐shading trees. By far the most important correlate of larval growth was the amount of water consumed with leaf mass (r=0.94). When variance in water intake was standardized (also largely eliminating parallel variation in proteins), fructose and glucose still had significant positive correlations and proanthocyanidins negative with larval growth on control but not on shade leaves. Concentrations of several phenolic compounds correlated negatively with intake of dry matter and especially water, and different phenolics were important in shaded (gallotannins) and in control (flavonoids) leaves. Our findings strongly suggest that the effects of putatively defensive leaf traits on insect consumption and growth interact with nutritive leaf traits, particularly with water.     

遮光和施氮对暗紫贝母形态特征和生物量分配的影响

根据最优分配理论( optimal partitioning theory,OPT),在自然环境中,由于地上和地下资源在空间上的分离,陆生植物需要调整其地上和地下部分的生物量分配以平衡对资源的吸收。研究结果[1-2]显示：在植物地上资源严重受限时,叶片的生物量分配相对增加;而地下资源严重受限时,根的生物量分配相对增加。然而,植物的生物量分配对资源的响应较为复杂。首先,除了生物量分配,形态变化也是植物调节资源吸收的重要手段,例如,植物通过增加比叶面积提高对光照的吸收,通过调整比根长响应土壤养分的变化[3-4];并且,一些植物甚至以形态响应为主,生物量分配的变化并不明显[3,5]。此外,某些植物还有一些特殊的资源平衡方式,例如,克隆植物通过构件之间的养分传输平衡资源在空间上的分配不均[6];拥有特化储藏器官的植物可依靠大量储藏物质来平衡资源在时间上的分配不均[7]。植物所具有的丰富的资源响应方式决定了其多样的资源策略。     

不同遮光处理对川西柳叶菜部分形态、生长和生理指标的影响

以自然光照为对照,对轻度、中度和重度遮光条件下(遮光率分别为24%、48%和72%)川西柳叶菜( Epilobium fangii C. J. Chen et al.)的部分形态、生长和生理指标进行比较分析。分析结果显示：遮光处理对川西柳叶菜的MDA含量无显著影响,对叶长、花冠宽、叶干质量分配比例以及叶绿素a( Chla)、叶绿素b( Chlb)和类胡萝卜素(Car)含量及Chla/Chlb值有显著影响(P<0.05),对其余指标有极显著影响(P<0.01)。与对照相比,3个遮光处理组的单株根数、株高、主茎长和基径总体上显著下降,根长在轻度和中度遮光条件下略升高、在重度遮光条件下显著升高;3个遮光处理组的单株叶片数和叶长总体上显著下降,叶宽在轻度和中度遮光条件下略下降、在重度遮光条件下显著升高,叶厚在轻度遮光条件下显著升高、在中度遮光条件下略下降、在重度遮光条件下显著下降;3个遮光处理组的花柄长、花管长和花冠高显著升高,单株开花数在轻度遮光条件下略下降、在中度遮光条件下显著升高、在重度遮光条件下显著下降,花冠宽在轻度和中度遮光条件下略升高、在重度遮光条件下显著升高。与对照相比,3个遮光处理组的全株干质量和茎干质量分配比例均显著下降;根干质量分配比例和根冠比在轻度遮光条件下显著升高、在中度和重度遮光条件下略下降;地上部干质量分配比例在轻度遮光条件下显著下降、在中度和重度遮光条件下略升高;叶干质量分配比例在轻度和中度遮光条件下略下降、在重度遮光条件下略升高。在轻度和中度遮光条件下,叶片的Chla、Chlb和Car含量基本上显著高于对照,Chla/Chlb值分别略低于或显著低于对照;而在重度遮光条件下这4个指标均略高于对照。与对照相比,轻度和中度遮光条件下叶片的H2 O2含量和SOD活性略升高,MDA含量和总抗氧化能力略下降;总酚含量在轻度遮光条件下略下降、在中度遮光条件下略升高;重度遮光条件下这5个指标均显著升高。随着遮光程度的增强,川西柳叶菜的单株根数、株高、主茎长、基径和叶厚逐渐下降,而叶宽、全株干质量、叶干质量分配比例、H2 O2含量、SOD活性和总酚含量逐渐升高;其中,在中度遮光条件下,其单株开花数、花柄长、花管长、花冠高、花冠宽和花干质量分配比例最高。结果表明：在遮光条件下,川西柳叶菜可在形态、生长和生理上调整生长策略,完成发育过程;并且,中度遮光有利于其生殖分配,提高其观赏价值。     

Salt-stress effects on avocado rootstock growth. I. Establishing criteria for determination of shoot growth sensitivity to the stress

The mechanisms of shoot growth inhibition under salt-stress are not yet understood. Comparative evaluation of growth tolerance level of plant material used for mechanistic studies into stress effect on growth processes is a critical step towards establishing a plant model system for studies of stress effects on growth.In the present study, numerous vegetative shoot-growth parameters were evaluated as criteria for determination of shoot growth sensitivity of avocado rootstocks (Persea americana Mill.) to salt-stress. Seven different West-Indian rootstocks were investigated for their growth response to the stress. The plants, grown in 50 L soil-filled containers, were treated with 4 mM Na and 6 mM Cl (control) or 18 mM Na and 20 mM Cl (salt) for a period of 3 years. Changes in trunk diameter, branch diameter, number of new branches, branch fresh weight (FW) and dry weight (DW), leaf length, leaf area, leaf number, leaf FW and DW and distribution of the leaf population into size classes, were quantified during the season of rapid shoot growth, and used for grading growth sensitivity.The seven rootstocks studied were ranked according to the sensitivity of their vegetative growth to the stress. The order of sensitivity was found to be similar when the ranking was based on changes in DW and FW deposition per branch, cumulative leaf area and leaf weight per branch, or branch stem weight. Stress effects on leaf FW deposition were similar to the effect on total branch FW. Stress effects on branch stem FW were closely related to total branch DW deposition. Inhibition of cumulative leaf area per branch was less sensitive to the stress than deposition of FW or DW biomass. Biomass production per branch, or alternatively leaf biomass production per branch, is suggested as a practical parameter for evaluation of avocado rootstock shoot growth sensitivity to salt-stress.     

光照条件、植株冠层结构和枝条寿命的关系——以桂花和水杉为例

根据衰老理论的代谢率假说,生物寿命与其代谢率有关,个体大小相同的生物体,在质量较好的微生境中通常比较差生境中具有更高的代谢速率。因此,生物体在资源供给较差的生境中通常比资源供给较充足的生境中具有更长的寿命。枝条是木本植物植冠构建的基本单元之一,如果枝条遵循代谢率假说,则可推测在光照较好环境下的植物枝条或小枝将比其在遮荫环境下具有更短的寿命,即枝条寿命与光照条件成反比。以常绿物种桂花(Osmanthus fragrans)和落叶物种水杉(Metasequoiaglyptostroboides)为研究对象,通过测量不同光照环境下,植株大小(株高和胸径)、冠层深度、冠层轮廓(冠层深度/冠层宽度)、相对冠层宽度(冠层宽度/植株高度)以及植株凋落枝条寿命等性状,探讨了光照条件对成年植株冠层形态结构和植株枝条寿命的影响。调查发现:1)枝条的寿命在遮荫条件下显著高于全光照条件下,与理论预测吻合;2)随遮荫程度增加,植株冠层深度和冠层轮廓增加,相对冠层宽度减小;3)枝条的平均寿命与植株冠层深度和冠层轮廓成正比,与植株相对冠层宽度成反比。这表明光照条件可能通过改变植株冠层结构来影响枝条寿命。未来需要进一步研究枝条生物量分配、叶片光合能力和呼吸速率在不同生活型物种之间的差异,以便更全面的理解枝条寿命与生境质量之间的关系。     

狭叶红景天幼苗对水分及遮阴的生长及生理生化响应

研究植物对水分和遮阴胁迫的响应及其生理机制对制定合理的栽培管理措施十分必要。以红景天属植物为研究对象,设置土壤含水量分别为田间持水量的80%(过湿水分)、70%(正常水分)、60%(轻度干旱)、40%(中度干旱)、20%(重度干旱)5个水分梯度;设置2个遮阴处理,以全光照(遮阴率为0)为对照、黑色遮阴网遮阴(遮阴率为85%),研究狭叶红景天生长及生理生化指标的变化特征。结果表明:在不同水分处理下,与对照相比,叶绿素含量、茎干重和茎重比(SMR)显著增加(P0.05),株高、总生物量、叶面积、叶干重、叶重比(LMR)、比叶面积(SLA)、叶面积比(LAR)和叶面积根干重比(LARMR)增加,根冠比和根重比(RMR)减少;随着干旱程度加剧,丙二醛(MDA)、脯氨酸(Pro)和可溶性糖(Ss)含量增加,超氧化物歧化酶(SOD)活性总体呈先增加后减小的趋势。在遮阴处理下,株高、SMR、SLA、LAR和LARMR显著增加(P0.05),叶绿素SPAD值和叶面积增加,总生物量、根干重、根冠比和LMR显著减少(P0.05),茎干重和叶干重减少,MDA含量显著增加,Pro含量略有下降,Ss含量减少。在水分胁迫下,狭叶红景天中度干旱时通过增加酶活性抵御伤害,重度干旱超过其阈值,SOD活性下降,植物体受到伤害,Ss可能是主要的渗透调节物质。在遮阴处理下,狭叶红景天通过增加SLA避免遮阴伤害。狭叶红景天在受到环境胁迫时会通过形态改变、调节MDA含量、抗氧化酶活性和渗透调节物质来保证自身正常的生长发育。