喜旱莲子草在增温背景下的密度制约与生长权衡

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 喜旱莲子草在增温背景下的密度制约与生长权衡 DOI: 10.5846/stxb202105111231 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 第二次青藏高原综合科学考察研究项目（2019QZKK0304）；西华师范大学基本科研业务费资金资助（17B007）；四川省教育厅重点项目（18ZA0462） Density dependence and growth trade-off of Alternanthera philoxeroides under warming Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究植株个体与种群数量的关系对探究植物的适应策略、理解植物入侵机理有重要意义。但多数研究着眼于常温处理下植株响应密度变化的生长权衡，对增温处理下植株的密度制约调节机理和常温与增温处理下响应密度变化的调节规律是否发生变化认识不足。以喜旱莲子草（Alternanthera philoxeroides）为研究对象，采用密度（1、5、9株/盆，37、186、335株/m2）和温度（常温、增温）双因素实验设计，探究了全球变暖背景下，密度制约与喜旱莲子草的关系、地上与地下部分的密度制约调节规律。结果表明：（1）地上构件特征与温度呈显著正相关关系（P<0.05），地上构件特征和比叶面积表现出明显密度依赖性（P<0.05）。温度与种群密度及其交互作用对地下指标无显著影响（P>0.05）。（2）无论增温与否，随密度压力增加，根生物量分配比率增大，各构件平均生物量、茎生物量分配比率降低。叶生物量分配比率在各密度下维持恒定。（3）用生物量-密度异速指数γ衡量种群密度调控强弱。常温处理下，γleaf（-1.685） < γabove-ground（-1.612） < γstem（-1.605） < γ individual（-1.558） < γroot（-1.524），受密度制约调控强度的大小依次为：叶>地上>茎>个体>根。增温处理下，γstem（-2.075） < γabove-ground（-2.038） < γindividual（-1.982） < γleaf（-1.933） < γroot（-1.800），受密度制约调控强度的大小依次为：茎 > 地上 > 个体 > 叶 > 根。喜旱莲子草种群地上构件受密度的调节作用强于地下构件。由此可见，无论增温与否，喜旱莲子草种群地下资源的竞争能力随密度增加而增强，地上资源竞争能力随密度增加而减弱，喜旱莲子草地上部分调节强于地下部分，常温处理下，叶受密度制约作用更强，增温处理下，茎受密度制约最强。根受密度制约最弱。地上资源的竞争占主导地位。 Abstract:Study on the relationship between plant individual and population is of great importance to explore plant adaptation strategies and to understand the mechanisms of plant invasion. However, most studies focused on the growth trade-off of plant response to density change under normal temperature treatment. There is a lack of understanding on the regulation mechanism of plant density restriction under increasing temperature treatment, and whether the regulation law of response to density change alters under normal temperature and warming treatment. In this study, taking Alternanthera philoxeroides as the focus species, the relationship between density restriction and A. philoxeroides, and the regulation law of density restriction between aboveground and underground parts under the background of global warming were studied by using two-factor experimental design of density (1, 5, 9 plants/pot, 37, 186, 335 plants/m2) and temperature (normal temperature, increasing temperature). The results showed that:(1) There was a significantly positive correlation between the characteristics of aboveground components and temperature (P<0.05), and there was a significant density dependence on the characteristics and specific leaf area of aboveground components (P<0.05). Temperature, population density and their interaction had no significant effect on underground index (P>0.05). (2) With the increase of density, the root biomass allocation ratio increased, while the average biomass and stem biomass allocation ratio decreased under two temperatures. The allocation ratio of leaf biomass remained constant at different densities. (3) The allometric index γ of biomass-density was used to measure the regulation of population density. Under normal temperature treatment, we found that γleaf (-1.685) < γabove-ground(-1.612) < γstem (-1.605) < γ individual (-1.558) < γroot(-1.524). Regulation intensity restricted by density was in the following order:leaf > aboveground > stem > individual > root. Under warming treatment, we found that γstem (-2.075) < γabove-ground (-2.038) < γindividual(-1.982) < γleaf (-1.933) < γroot (-1.800). The order of regulation intensity restricted by density was stem > aboveground > individual > leaf > root. The density regulation of the aboveground components of A. philoxeroides population is stronger than that of the underground ones. That's to say, whether warming or not, the competitiveness of underground resources of A. philoxeroides population increases with the increase of density, while the competitiveness of aboveground resources decreases with the increase of density. The regulation ability of the upper part of A. philoxeroides is stronger than that of underground part. Under normal temperature treatment, leaves are more restricted by density, while stems are most restricted by density under warming treatment. The competition for aboveground resources is dominant for A. philoxeroides. 参考文献 相似文献 引证文献