首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 578 毫秒
1.
许振柱  周广胜  肖春旺  王玉辉 《生态学报》2004,24(10):2186-2191
研究利用大型环境生长箱模拟了两种沙地优势灌木柠条和羊柴对 CO2 浓度倍增和土壤干旱交互作用的响应。 CO2 浓度倍增使柠条和羊柴的生物量分别增加了 6 2 .90 %和 5 0 .0 0 % ,使植株叶面积分别增加了 4 1.86 %和 4 5 .84 %。 CO2 浓度的倍增效应随着土壤干旱的增加而下降。 CO2 浓度倍增和土壤干旱都增加单位叶面积质量 (L MA) ,但 CO2 浓度倍增主要增加了水分充足时的 L MA。 CO2 倍增使柠条和羊柴叶片含氮量分别降低了 10 .4 0 %和 5 .0 6 %。柠条叶片含氮量在所有土壤干旱条件下均呈现出增加的趋势 ,而羊柴叶片的含氮量仅在严重干旱条件下增加。 CO2 倍增使叶片的碳氮比显著增加 ,但土壤干旱使之降低。CO2 浓度倍增降低叶肉细胞质膜的过氧化产物丙二醛 (MDA )的含量 ,干旱使之增加。叶片含氮量与 MDA呈显著正相关。研究表明 CO2 倍增有保护叶片免受严重土壤干旱的作用 ,但干旱的负面影响是 CO2 倍增效应所难以弥补的  相似文献   

2.
不同土壤水分下4种沙生灌木的光合光响应特性   总被引:21,自引:1,他引:20  
韩刚  赵忠 《生态学报》2010,30(15):4019-4026
采用盆栽试验在适宜水分、中度干旱和重度干旱(土壤田间持水量的70%-75%、45%-50%和30%-35%)条件下,研究了4种沙生灌木柠条、花棒、沙木蓼和杨柴1年生幼苗的光合光响应特性。结果表明:各灌木光响应曲线的变化趋势基本一致,采用非直角双曲线模型拟合良好;各灌木净光合速率在同等光合有效辐射时均表现为适宜水分中度干旱重度干旱;各灌木在干旱条件下叶片表观量子效率与最大净光合速率均较适宜水分下降低,两项参数在中度与重度干旱下的平均降幅柠条均为最小,反映出柠条光合作用对干旱胁迫较强的适应性;干旱条件下光饱和点的降低是造成4种沙生灌木对光照需求改变的主要原因,光补偿点和饱和点的协同变化表明柠条具有对光环境良好的适应性;4种沙生灌木在干旱条件下暗呼吸速率均降低。在西北沙区人工植被建设中从光合特性考虑,柠条更宜作为土壤水分较差立地上的先锋树种。  相似文献   

3.
CO2倍增及UV-B增强对大豆植株生长和根际微生物的影响   总被引:5,自引:0,他引:5  
以大豆'齐黄27'为研究材料,采用人工气候室模拟大气CO2浓度倍增(350~700 μmol*mol-1)及紫外线B(UV-B,280~320 nm)辐射增强(4~15 μW*cm-2)的环境条件,研究了CO2浓度增加及UV-B辐射增强对大豆生育前期的生长及根瘤、根际微生物数量的影响.结果表明:(1)增强UV-B能显著减少大豆植株地上部生物量,而对株高的抑制作用不显著;CO2浓度倍增促使大豆株高和地上生物量显著增加,对根系生物量的促进作用不显著,但能够减轻UV-B辐射增强对地上及根系生物量的抑制作用;CO2浓度增加、UV-B辐射增强及其复合胁迫均导致大豆植株根冠比下降,且复合胁迫对根冠比的抑制作用更明显.(2)CO2浓度倍增降低了大豆叶片叶绿素、类胡萝卜素及花青素含量,提高了净光合速率;UV-B辐射增强导致叶绿素含量减少,光合速率下降,却增加了类胡萝卜素及花青素含量;CO2浓度增加、UV-B辐射增强复合处理对叶片色素含量及光合速率的影响具有复合效应.(3)CO2浓度倍增能够促进根瘤数量及根际真菌数量的增加,而UV-B增强处理则显著降低细菌和放线菌的数量;CO2浓度倍增能够缓解UV-B增强处理对放线菌的抑制作用,却导致根际细菌数量进一步减少.研究发现,CO2浓度增加及UV-B辐射增强对大豆生育前期植株生长、叶片色素含量及根际微生物数量存在抑制或促进效应,而且在某些性状上存在复合效应,它们可能主要是通过调节大豆植株的干物质分配及根系的代谢间接影响根瘤数量及根际微生物数量.  相似文献   

4.
利用开顶式气室对春小麦进行了一个生长季的CO2倍增盆栽实验,土壤水分控制为3个水平(分别为田间持水量(FWC)的80%、60%、40%).结果显示,CO2倍增显著提高小麦的光合速率.但在相同的CO2测定浓度下, 生长在加倍CO2浓度下的小麦的光合速率比当前CO2浓度下小麦低22%.高CO2浓度显著促进小麦生长,相对增加幅度在适宜水分下最大,为14.8%.80%FWC水分条件下高CO2使植株的干重/高度比增加15.7%.高CO2条件下,小麦的蒸腾速率降低、累积耗水量减少、水分利用效率(WUE)提高,WUE的提高幅度在适宜水分下最大,为30%.干旱(40%FWC)使小麦地上干重和WUE在当前CO2条件下分别降低72%和19%,加倍CO2条件下降低幅度较大,分别为76%和23%.根据以上结果得出结论: (1) 高CO2条件下, 小麦的光合速率、地上生物量和水分利用效率提高;(2) 植物长期生长于高CO2浓度导致光合能力降低;(3) 高CO2对植物侧向生长的促进作用大于垂直生长,即高CO2下植株将相对粗壮;(4) 高CO2对植物的生态效应依赖于土壤水分,在适宜水分下相对较大;(5) 在未来高CO2条件下,干旱引起的减产和水分利用效率减低幅度将会更大.  相似文献   

5.
CO2倍增对不同氮水平下小麦幼苗根系及叶片NR活性的影响   总被引:2,自引:0,他引:2  
以小麦品种'小偃22'幼苗为材料,采用开顶式气室和水培实验研究了不同供氮水平(2.5、5.0、10.0和 15.0 mmol·L-1)下小麦幼苗植株生长量、根系形态、有机碳分泌速率和硝酸还原酶(NR)活性对大气CO2浓度升高的响应.结果显示,大气CO2浓度倍增均增加了小麦幼苗各生长阶段根冠生物量以及根系长度、面积、有机碳分泌速率和叶片NR活性.随供氮水平的提高,各生长阶段幼苗根冠生物量、根长和面积以及叶片NR活性呈上升趋势,而有机碳分泌速率呈下降趋势;根冠比变化不同阶段表现不一致,一叶一心期呈下降趋势,二叶一心期和三叶一心期分别以15.0和10.0 mmol·L-1氮水平较高.研究表明,大气CO2浓度升高可促进小麦幼苗根系生长和有机碳分泌速率,提高其氮素同化能力;增加介质供氮有利于高CO2浓度条件下小麦幼苗根冠生长和氮素同化,提高根冠比,减少根系有机碳过度分泌引起的碳损耗.  相似文献   

6.
CO2浓度升高和干旱对春小麦生长和水分利用的生态效应   总被引:6,自引:0,他引:6  
利用开顶式气室对春小麦进行了一个生长季的CO2倍增盆栽实验,土壤水分控制为3个水平(分别为田间持水量(FWC)的80%,60%,40%)。结果显示,CO2倍增显提高小麦的光合速率。但在相同的CO2测定浓度下,生长在加倍CO2浓度下的小麦的光合速率比当前CO2浓度下小麦低22%。高CO2浓度显促进小麦生长,相对增加幅度在适宜水分下最大为14.8%。80%FWC水分条件下高CO2使植株的干重/高度比增加15.7%,高CO2条件下,小麦的蒸腾速率降低,累积耗水量减少,水分利用效率(WUE)提高,WUE的提高幅度在适宜水分下最大,为30%。干旱(40%FWC)使小麦地上干重和WUE在当前CO2条件下分别降低72%和19%,加倍CO2条件下降低幅度较大,分别为76%和23%。根据以上结果得出结论:(1)高CO2条件下,小麦的光合速率,地上生物量和水分利用效率提高;(2)植物长期生长于高CO2浓度导致光合能力降低;(3)高CO2对植物侧向生长的促进作用大于垂直生长,即高CO2下植株将相对粗壮;(4)高CO2对植物的生态效应依赖于土壤水分,在适宜水分下相对较大;(4)在未来高CO2条件下,干旱引起的减产和水分利用效率减低幅度将会更大。  相似文献   

7.
李文婷  张超  王飞  郑明清  郑元润  张峰 《生态学报》2010,30(5):1192-1199
沙埋与水分是影响毛乌素沙地植物存活、生长的关键因子。通过沙埋与供水的野外控制实验,研究了毛乌素沙地重要物种柠条(Caragana korshinskii)与羊柴(Hedysarum laeve)幼苗存活及生长对沙埋和供水的反应。结果表明:适量的沙埋(0.25H-0.50H沙埋,H为苗高)与供水(柠条50mm/月,羊柴75mm/月)可以促进幼苗生长,过量的沙埋与供水则会抑制生长甚至导致幼苗死亡。柠条幼苗在50mm/月供水,0.25H、0.50H沙埋,羊柴幼苗在75mm/月供水,0.25H、0.50H沙埋下具有较高的相对生长速率和净同化速率;幼苗在1.0H和1.25H沙埋下全部死亡。供水量较小、沙埋较浅时,两种植物根冠比均较高;当供水量最大时,柠条幼苗根冠比在沙埋最深和没有沙埋时较大,而羊柴幼苗根冠比仍在没有沙埋时最高。  相似文献   

8.
油蒿和羊柴为毛乌素沙地的共生优势物种, 然而关于土壤水分对其种间关系的研究相对较少。设置低水(200mL)、中水(300 mL)和高水(400 mL)三个水分处理水平及单独和混合生长两种种植方式, 通过油蒿和羊柴的生长响应,来研究不同水分供应条件下两物种种间关系的变化。结果表明: 水分处理显著提高了油蒿的株高和基径以及羊柴的基径, 竞争存在与否对两物种的形态生长指标均没有显著影响。在生物量积累方面, 水分处理对于油蒿总干重的影响表现为先增加后降低, 且主要是在混合生长条件下; 水分显著降低单独生长油蒿的根冠比。竞争对油蒿总干重的促进作用主要是在中水条件下, 对其根冠比的抑制作用是在低水条件下。对于羊柴, 水分处理显著提高其总干重而降低其根冠比, 竞争仅对其总干重有显著的降低作用且是在中水条件下。通过对相对竞争系数的进一步研究发现, 油蒿和羊柴的种间关系表现为在低水、高水下竞争, 在中水条件下共存, 并且两物种的相对竞争能力随处理的时间而变化。上述实验结果表明, 中等水分供应条件对两物种的共存是有利的, 这可为毛乌素优势群落的管理提供一定的理论参考。  相似文献   

9.
改变土壤根系的分布以汲取深层土壤水分的能力是植物避免干旱的主要策略。山黧豆是一种抗逆性强的豆类作物,该研究通过起垄条播控制性沟灌的方式,设置传统灌溉(FI)、交替灌溉(PRD,灌水量减少50%)和不灌溉(NI)3种处理模式,探索不同灌溉模式对播种后不同时期山黧豆土壤水分、根系分布、叶片气体交换、水分利用效率和籽粒产量的影响。结果表明:(1)在FI、PRD和NI处理下,山黧豆的根系分别有89.8%、86.9%和84.9%生长在0~20 cm的表层土壤中;干旱胁迫使PRD和NI处理下深层土壤中根系的比例提高至13.05%和15.07%。(2)在整个生育期内,土壤干旱显著降低了山黧豆叶片的净光合速率、蒸腾速率和气孔导度;在种植后60 d时,PRD和NI处理下叶片的瞬时水分利用效率分别较FI处理显著提高了21.4%和14.9%。(3)干旱胁迫显著降低了山黧豆植株高度、第一豆荚高、平均结荚数和豆粒数以及地上部和根系的干重,但显著增加了根冠比;PRD处理对豆荚长度、豆荚重和每荚豆粒重没有显著影响;PRD和NI处理下山黧豆平均籽粒产量分别比FI处理显著降低了53%和63%。研究发现,在干旱胁迫条件下,山黧豆能够通过提高深层土壤中根系的比例、更多吸收深层土壤水分、显著增加根冠比以及显著提高生殖生长期叶片的瞬时水分利用效率,减轻干旱胁迫对自身生长的影响。该研究结果可为山黧豆在旱区推广种植提供理论依据。  相似文献   

10.
杨柴对高CO2浓度和土壤干旱胁迫的响应   总被引:11,自引:0,他引:11  
毛乌素优势植物杨柴 (HedysarummongolicumTurcz.)对高CO2 浓度和土壤干旱胁迫响应的研究结果表明 :干旱胁迫可使杨柴根系伸长 ,根生物量、地径、主茎高和茎生物量下降 ;高CO2 浓度使杨柴根和茎生物量明显增加 ,CO2 的“施肥效应”显著 ,干旱使CO2 的“施肥效应”减弱。同时 ,土壤干旱胁迫使杨柴的根 /冠比增加 ,说明在土壤干旱胁迫情况下根的生长比地上部分 (茎 )的生长更活跃 ,有利于提高杨柴在干旱沙漠地区的固沙作用 ;CO2 浓度升高和土壤干旱胁迫均使杨柴叶片的水势下降 ,叶片水势的下降使叶片细胞对水分的束缚力增强 ,从而减少植物蒸腾耗水 ,有利于提高水资源的利用效率  相似文献   

11.
Impacts of either elevated CO2 or drought stress on plant growth have been studied extensively, but interactive effects of these on plant carbon and nitrogen allocation is inadequately understood yet. In this study the response of the dominant desert shrub, Caragana intermedia Kuanget H.c.Fu, to the interaction of elevated CO2 (700 ± 20 μmol mol−1) and soil drought were determined in two large environmental growth chambers (18 m2). Elevated CO2 increased the allocation of biomass and carbon into roots and the ratio of carbon to nitrogen (C:N) as well as the leaf soluble sugar content, but decreased the allocation of biomass and carbon into leaves, leaf nitrogen and leaf soluble protein concentrations. Elevated CO2 significantly decreased the partitioning of nitrogen into leaves, but increased that into roots, especially under soil drought. Elevated CO2 significantly decreased the carbon isotope discrimination (Δ) in leaves, but increased them in roots, and the ratio of Δ values between root and leaf, indicating an increased allocation into below-ground parts. It is concluded that stimulation of plant growth by CO2 enrichment may be negated under soil drought, and under the future environment, elevated CO2 may partially offset the negative effects of enhanced drought by regulating the partitioning of carbon and nitrogen.  相似文献   

12.
Recent (13) CO(2) canopy pulse chase labeling studies revealed that photosynthesis influences the carbon isotopic composition of soil respired CO(2) (δ(13) C(SR)) even on a diel timescale. However, the driving mechanisms underlying these short-term responses remain unclear, in particular under drought conditions. The gas exchange of CO(2) isotopes of canopy and soil was monitored in drought/nondrought-stressed beech (Fagus sylvatica) saplings after (13) CO(2) canopy pulse labeling. A combined canopy/soil chamber system with gas-tight separated soil and canopy compartments was coupled to a laser spectrometer measuring mixing ratios and isotopic composition of CO(2) in air at high temporal resolution. The measured δ(13) C(SR) signal was then explained and substantiated by a mechanistic carbon allocation model. Leaf metabolism had a strong imprint on diel cycles in control plants, as a result of an alternating substrate supply switching between sugar and transient starch. By contrast, diel cycles in drought-stressed plants were determined by the relative contributions of autotrophic and heterotrophic respiration throughout the day. Drought reduced the speed of the link between photosynthesis and soil respiration by a factor of c. 2.5, depending on the photosynthetic rate. Drought slows the coupling between photosynthesis and soil respiration and alters the underlying mechanism causing diel variations of δ(13) C(SR).  相似文献   

13.
* Greater fine-root production under elevated [CO2] may increase the input of carbon (C) and nitrogen (N) to the soil profile because fine root populations turn over quickly in forested ecosystems. * Here, the effect of elevated [CO)] was assessed on root biomass and N inputs at several soil depths by combining a long-term minirhizotron dataset with continuous, root-specific measurements of root mass and [N]. The experiment was conducted in a CO(2)-enriched sweetgum (Liquidambar styraciflua) plantation. * CO2) enrichment had no effect on root tissue density or [N] within a given diameter class. Root biomass production and standing crop were doubled under elevated [CO2]. Though fine-root turnover declined under elevated [CO2], fine-root mortality was also nearly doubled under CO2 enrichment. Over 9 yr, root mortality resulted in 681 g m(-2) of extra C and 9 g m(-2) of extra N input to the soil system under elevated [CO2]. At least half of these inputs were below 30 cm soil depth. * Increased C and N input to the soil under CO2 enrichment, especially below 30 cm depth, might alter soil C storage and N mineralization. Future research should focus on quantifying root decomposition dynamics and C and N mineralization deeper in the soil.  相似文献   

14.
荒漠植物梭梭和沙拐枣的花环结构及C4光合特征   总被引:20,自引:2,他引:18       下载免费PDF全文
 为了探讨梭梭(Haloxylon ammodendron)和沙拐枣(Calligonum mongolicum)适应高温强光荒漠环境的光合作用机构及特征,通过对其同化枝的解剖结构观察,δ13C值分析,以及气体交换测定表明:二者均具有花环结构(Kranz anatomy),肉细胞(Mesophyll cell)呈栅栏状,其内侧是维管束鞘细胞(Bundle sheath cell),小维管束与维管束鞘细胞相接。在栅栏组织和贮水组织中,梭梭具有形状巨大的含晶细胞;沙拐枣具有大量的粘液细胞。梭梭和沙拐枣同化枝的δ13C值分别为-14.3‰和-14.8‰,在不同生长季节和土壤水分条件下,二者的δ13C值变化在-14‰到-16‰之间。梭梭和沙拐枣的CO2补偿点分别为2 μmol•mol-1和4 μmol•mol-1,光饱和点分别为1 660和1 756 μmol•m-2•s-1,表观光合量子效率分别为0.044和0.057 mol CO2•mol-1 photons。这表明,广泛分布于我国荒漠地区的木本植物梭梭和沙拐枣为C4植物,其光合途径不随生长季节和水分条件的变化而改变。  相似文献   

15.
Global change factors affect plant carbon uptake in concert. In order to investigate the response directions and potential interactive effects, and to understand the underlying mechanisms, multifactor experiments are needed. The focus of this study was on the photosynthetic response to elevated CO(2) [CO2; free air CO(2) enrichment (FACE)], drought (D; water-excluding curtains), and night-time warming (T; infrared-reflective curtains) in a temperate heath. A/C(i) curves were measured, allowing analysis of light-saturated net photosynthesis (P(n)), light- and CO(2)-saturated net photosynthesis (P(max)), stomatal conductance (g(s)), the maximal rate of Rubisco carboxylation (V(cmax)), and the maximal rate of ribulose bisphosphate (RuBP) regeneration (J(max)) along with leaf δ(13)C, and carbon and nitrogen concentration on a monthly basis in the grass Deschampsia flexuosa. Seasonal drought reduced P(n) via g(s), but severe (experimental) drought decreased P(n) via a reduction in photosynthetic capacity (P(max), J(max), and V(cmax)). The effects were completely reversed by rewetting and stimulated P(n) via photosynthetic capacity stimulation. Warming increased early and late season P(n) via higher P(max) and J(max). Elevated CO(2) did not decrease g(s), but stimulated P(n) via increased C(i). The T×CO2 synergistically increased plant carbon uptake via photosynthetic capacity up-regulation in early season and by better access to water after rewetting. The effects of the combination of drought and elevated CO(2) depended on soil water availability, with additive effects when the soil water content was low and D×CO2 synergistic stimulation of P(n) after rewetting. The photosynthetic responses appeared to be highly influenced by growth pattern. The grass has opportunistic water consumption, and a biphasic growth pattern allowing for leaf dieback at low soil water availability followed by rapid re-growth of active leaves when rewetted and possibly a large resource allocation capability mediated by the rhizome. This growth characteristic allowed for the photosynthetic capacity up-regulations that mediated the T×CO2 and D×CO2 synergistic effects on photosynthesis. These are clearly advantageous characteristics when exposed to climate changes. In conclusion, after 1 year of experimentation, the limitations by low soil water availability and stimulation in early and late season by warming clearly structure and interact with the photosynthetic response to elevated CO(2) in this grassland species.  相似文献   

16.
草地植物根系碳储量和碳流转对CO2浓度升高的响应   总被引:2,自引:0,他引:2  
吴伊波  崔骁勇 《生态学报》2009,29(1):378-388
植物根系是陆地生态系统重要的碳汇和矿质养分库,也是土壤中碳及养分的主要来源,只有深入认识CO2浓度升高下根系的碳汇功能和根系周转对土壤碳库的影响,才能准确预测生态系统对全球变化的响应与反馈调节作用.介绍了CO2浓度升高对草地植物根系生物量、根系凋落物的数量和品质以及根系周转速率的影响,指出研究植物体内碳向根分配格局的变化趋势必须考虑CO2浓度升高的直接和间接两方面作用;在预测根系碳库储量的动态变化时,需要区分不同功能根系组分的生物量;为更准确估算根系周转速率,有必要确立草地植物根系直径与其寿命之间的关系;CO2浓度升高普遍提高根系凋落物的C/N,但以此判定其在土壤中的分解速率快慢并不可靠,需要进一步从机理上探究根系凋落物分解的控制因素.  相似文献   

17.
Stulen  I.  den Hertog  J. 《Plant Ecology》1993,(1):99-115
This paper examines the extent to which atmospheric CO2 enrichment may influence growth of plant roots and function in terms of uptake of water and nutrients, and carbon allocation towards symbionts. It is concluded that changes in dry matter allocation greatly depend on the experimental conditions during the experiment, the growth phase of the plant, and its morphological characteristics. Under non-limiting conditions of water and nutrients for growth, dry matter partitioning to the root is not changed by CO2 enrichment. The increase in root/shoot ratio, frequently observed under limiting conditions of water and/or nutrients, enables the plant to explore a greater soil volume, and hence acquire more water and nutrients. However, more data on changes in dry matter allocation within the root due to atmospheric CO2 are needed. It is concluded that nitrogen fixation is favored by CO2 enrichment since nodule mass is increased, concomitant with an increase in root length. The papers available so far on the influence of CO2 enrichment on mycorrhizal functioning suggest that carbon allocation to the roots might be increased, but also here more experiments are needed.Abbreviations LAR leaf area ratio - LWR leaf weight ratio - SWR stem weight ratio - RGR relative growth rate - R/S root/shoot - RWR root weight ratio  相似文献   

18.
Summary Artemisia tridentata seedlings were grown under carbon dioxide concentrations of 350 and 650 l l–1 and two levels of soil nutrition. In the high nutrient treatment, increasing CO2 led to a doubling of shoot mass, whereas nutrient limitation completely constrained the response to elevated CO2. Root biomass was unaffected by any treatment. Plant root/shoot ratios declined under carbon dioxide enrichment but increased under low nutrient availability, thus the ratio was apparently controlled by changes in carbon allocation to shoot mass alone. Growth under CO2 enrichment increased the starch concentrations of leaves grown under both nutrient regimes, while increased CO2 and low nutrient availability acted in concert to reduce leaf nitrogen concentration and water content. Carbon dioxide enrichment and soil nutrient limitation both acted to increase the balance of leaf storage carbohydrate versus nitrogen (C/N). The two treatment effects were significantly interactive in that nutrient limitation slightly reduced the C/N balance among the high-CO2 plants. Leaf volatile terpene concentration increased only in the nutrient limited plants and did not follow the overall increase in leaf C/N ratio. Grasshopper consumption was significantly greater on host leaves grown under CO2 enrichment but was reduced on leaves grown under low nutrient availability. An overall negative relationship of consumption versus leaf volatile concentration suggests that terpenes may have been one of several important leaf characteristics limiting consumption of the low nutrient hosts. Digestibility of host leaves grown under the high CO2 treatment was significantly increased and was related to high leaf starch content. Grasshopper growth efficiency (ECI) was significantly reduced by the nutrient limitation treatment but co-varied with leaf water content.  相似文献   

19.
在4种光照处理条件下(处理I:对所有分株光照处理;处理Ⅱ:对所有分株遮光处理;处理Ⅲ:仅对引入^13CO2的复合节分株进行遮光处理;处理Ⅳ:仅对引入^13CO2的复合节分株进行光照处理),分别从结缕草(Zoysia japonica Steud.)克隆植株的基部、中部和梢部(分别为第7、第17和第24复合节)分株引入^13CO2 ,对^13CO2在克隆植株不同器官内的分配格局及传输特征进行了研究。实验结果表明:从克隆植株的不同部位引入^13CO2,^13C的传输格局均表现出以引入点为起始点沿匍匐茎向基和向顶双向运输的趋势,但向顶传输的陡度值均小于向基传输的陡度值,向顶传输的距离则均大于向基传输的距离,说明”c的向顶传输更具优势。分株叶片、匍匐茎和复合节根中^13C的传输格局有一定差异;引入点分株叶中δ^13C值较高,其他分株叶中δ^13C值均迅速降低;匍匐茎内矿c值总体较低,但^13C传输范围广;当^13CO2引入点位于基部和中部时复合节根的δ^13C值高于匍匐茎,但当^13CO2引入点位于梢部时复合节根的δ^13C值低于匍匐茎。从^13C的传输范围及陡度值看,总体上分株叶中^13C的陡度值显著大于复合节根和匍匐茎;在匍匐茎中^13C呈现出平缓的传输格局但传输距离最远。此外,在4种光照处理条件下,处理Ⅳ的根及匍匐茎中13C向基或向顶传输的陡度值总体上均最高,且各器官^13C的传输距离均最远;但从基部、中部和梢部分株引入^13CO2后,分别在处理Ⅱ、处理Ⅲ和处理I的分株叶中^13C向基或向顶传输的陡度值均最高。根据实验结果,对不同光照条件下结缕草克隆植株不同器官内光合产物的分配格局及其生态效应进行了探讨。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号