克隆植物白刺繁殖分配与化学计量特征的关联及其对沙埋的响应

Many clonal plants are widely distributed in the arid desertificated area, which show the favorable ecological adaptation, and produce simultaneously a great deal of descendant ramet and seeds through clonal growth and sexual reproduction, respectively. The plant's allocation model greatly reflects its life history, while the ecological stoichiometry in plant are closely relative to its adaptation strategy. The project aims to elucidate the reproductive allocation and ecological stoichiometry characteristics and their relationships, and reveal the effects of sand burial on the reproductive allocation and the stoichiometric homoeostasis. Therefor, Nitraria tangutorum, the shoot-derived clonal plant, was selected as the study target species in this project. The artificial control trials were combined with the field survey experiments, and both the natural plants and the artificial plants were adopted in the experiment and sampling. The impact of ontogeny on the reproductive allocation with the biomass currency and meristem currency, and on the ecological stoichiometry were quantified, their allometric variation traits were elucidated. The relationship between the C:N:P stoichiometry and the reproductive allocation were analyzed based on the N and P addition experiment. The effect of sand burial on the reproductive allocation was explored in the case of synchronously examining the clonal growth and sexual reproduction. And the response of the ecological stoichiometric homoeostasis to sand burial was revealed. Finally, the ecological adaptation strategies of Nitraria tangutorum were put forward.

在干旱荒漠地区许多植物具有克隆繁殖能力，它们通过克隆生长与有性生殖产生了大量克隆分株和种子，具有良好的生态适应性。植物繁殖资源的分配模式很大程度上反映了植物生活史特征，同时植物的生态化学计量特征与其生态策略与适应密切相关。本项目旨在确定白刺植物的繁殖分配与生态化学计量特征及其相互关系，并揭示白刺繁殖过程中繁殖分配、生态化学计量学特征及内稳性对沙埋的响应机制。为此，本项目以白刺这种压条克隆型荒漠植物为研究对象，采取控制试验与野外调查试验相结合，人工植株与天然植株相结合的试验与取样方法，阐述白刺的生物量与分生组织两种分配通货的繁殖分配及化学计量特征在不同个体发育阶段下异速性变异特性；分析白刺C:N:P化学计量比与繁殖分配的关系；在同时考虑克隆繁殖与有性繁殖的情况下，研究沙埋对白刺繁殖分配的影响，以及生态化学计量学特性及内稳性对沙埋的响应。研究结果最终提出白刺的生态适应性策略。

干旱荒漠区植物白刺为了适应恶劣环境条件，其资源分配方式必然要满足其存活所需，且分配模式很大程度上反映了植物生活史特征，同时植物的生态化学计量特征与其生态适应性策略密切相关。本项目以内蒙古乌兰布和沙漠东北部地区唐古特白刺为研究对象，在布设了盆栽试验、样方断根试验、大田实验、沙埋试验的基础上，经过氮、磷肥料添加处理，探讨其生物量分配、分生组织分配两种资源分配方式，以及化学计量特征，并阐述其相互关系，同时揭示其沙埋条件下的资源分配规律。研究结果表明：1）氮磷添加改变了白刺果实的繁殖分配与营养器官生物量间的异速生长关系；2）白刺2015年、2016年、2017年萌生的枝条在平均生物量与分枝数量之间普遍存在着权衡关系，而叶片构件生物量与数量间不存在权衡关系，或在某些环境下其权衡关系才会体现出来；3）白刺通过某一构件生物量与氮含量能够较好的预测出其全株生物量与全株氮含量；4）氮添加影响幼苗芽库容量，且对幼苗芽库内组分的相对位置产生了不同影响。氮平衡指数与白刺幼苗出芽强度、分枝强度、二级枝和三级枝出芽率均呈二次非线性正相关关系；植株氮含量、氮积累量和地下部分形态特征分别与芽和营养枝数量呈正相关关系，与休眠芽和休眠枝数量呈负相关关系；5）施肥和年均显着影响芽的动态模式，保留生长潜力，营养生长强度和有性繁殖力的异速性显着。磷含量和相关比与白刺分株的芽动态指数更为密切相关；6）轻度沙埋处理对白刺幼苗二级枝的影响最明显，能显著增加白刺幼苗二级枝生物量、叶生物量、叶片数量和总叶面积，这说明轻度沙埋能促进白刺幼苗分枝的生长，而过度沙埋则对其产生抑制作用。研究结果很好地说明了白刺在生物量分配与分生组织分配上变化规律及其相应的化学计量特征的关联，并且对其在沙埋条件的生物量分配有助于解释其野外生存现象，这些研究结果将有助于揭示白刺的生态适应性策略。