沉水植物是水生生态系统中重要的组成部分，对它的生长繁殖策略进行研究能够为沉水植被的多样性保护和植物修复提供技术支持。水生植物在生长繁殖的过程中会受到生物或者非生物因子的影响，在面对不同的生境条件时会展现出多样化的生态适应性对策。关于水生克隆植物对生境条件的响应研究较少，因此，我们选择寒温带典型水生克隆植物线叶黑三棱(Sparganium angustifolium Michx)作为研究对象，通过野外调查和受控实验来研究不同的生命时期中线叶黑三棱对环境干扰所表现出的繁殖对策、克隆可塑性、觅食行为以及对入侵种的防御策略。 论文的第一部分主要围绕线叶黑三棱的繁殖方式展开。 首先，野外调查发现：在自然生境条件下，线叶黑三棱的萌发情况显示，同时期内有性繁殖方式的幼苗萌发数高于无性繁殖，但调查期内各月份萌发幼苗的株高和生物量多显示没有显著差异；水环境的各项指标中，水位和水流速对两种繁殖方式的幼苗萌发数、生物量以及株高影响最大。然后，通过控制实验“环境因子对线叶黑三棱有性繁殖的影响”发现：水位、温度和分布深度三个因素对线叶黑三棱种子的萌发影响较大，其中不同程度的水位波动和温度变化有利于萌发，而分布深度与萌发情况呈负相关；营养梯度对种子的萌发率则没有显著影响。 论文的第二部分主要围绕线叶黑三棱在生长期内对环境干扰的可塑性反应展开。 首先，野外调查发现：随着时间的变化，在自然环境的流水和静水中，沉水型线叶黑三棱增加了对地下部分的投资，但它的总生物量要低于挺水型线叶黑三棱。随着水位的升高，沉水型和挺水型线叶黑三棱不仅都增加了对地下部分的资源分配，同时株高也显著增大，且同等水深中挺水型线叶黑三棱的株高和地下生物量都要高于沉水型线叶黑三棱；而沉水型线叶黑三棱的克隆分株数虽然随水深而下降，但同等水深时要显著多于挺水型线叶黑三棱。然后，通过“异质性基质与水位波动下线叶黑三棱的生长表现”和“流水生境中线叶黑三棱的克隆可塑性”两个实验发现：相比于土壤营养均质性基质，土壤营养异质性基质并没有对线叶黑三棱的生长起到积极的作用，但两种异质性基质中植物的生物量积累有显著差异。线叶黑三棱受到高水位胁迫时，会增加对地上部分的投资来获取光照资源；高水位下有性繁殖受阻，无性繁殖依然是其主要的繁殖方式。相对于静水生境，处于流水生境中的线叶黑三棱产生了更多的分株数和更长的匍匐茎，并且形成了流线型的叶片，这些形态结构能够缓解水流带来的压力；同时，线叶黑三棱增加了地下部分的资源配置(生物量和克隆分株数等)，这些可塑性表现提高了植株在流水生境中的定植固着能力。最后，通过“线叶黑三棱在模拟升温和水位梯度下的繁殖策略”和“线叶黑三棱种群对入侵种的抵抗策略”两个实验发现：随着水位的上升，线叶黑三棱的株高受到显著影响；而在升温条件下，它的无性繁殖占主导地位，克隆分株的数量及各部分生物量的投资均有增加，与之相反的是有性繁殖的种子生物量逐渐减少。低水位条件下，相比于沉水型和挺水型外来入侵植物，漂浮型外来入侵植物凤眼莲和大藻通过占据水体上层生态位，对线叶黑三棱的生长繁殖产生了显著的影响。这说明线叶黑三棱主要通过水平方向的克隆生长来进行捕获光照和营养资源，其种群对其他两种生活型的入侵植物有较强的抵抗力。 综上所述，不同的环境因子、生物因素以及物种特性决定了线叶黑三棱在面对生境异质性时表现出不同的繁殖方式和形态特征。面对环境干扰时，线叶黑三棱主要通过增加对无性繁殖的比例以及调整生物量的分配比例等方式产生相应的生长繁殖对策。 关键词：环境异质性；繁殖策略；资源配置；形态可塑性；线叶黑三棱。

 Submerged macrophytes are an important part of aquatic ecosystem. The study of their growth and reproduction strategies can provide technical support for the diversity protection and phytoremediation of submerged vegetation. Aquatic plants are affected by biological or abiotic factors in the process of growth and reproduction. Therefore, aquatic plants will show diversified ecological adaptability to different habitat conditions. However, little research has been done on the response of aquatic clonal plants to habitat conditions. Thus, we choose typical aquatic clonal plants of S.angustifolium in cold temperate zone as the research materials. Field investigation and controlled experiments were used to study the reproductive strategies, clonal plasticity, foraging behavior and defense strategies against invasive species of S.angustifolium in different life stages. The first part of the paper mainly focuses on the reproductive mode of S.angustifolium. Firstly, field investigation showed that under natural habitat conditions, the number of seedlings germinated by sexual reproduction was higher than that by asexual reproduction in the same period, but there was no significant difference in plant height and biomass of germinated seedlings. Among all the indexes of water environment, water level and water velocity have the greatest influence on the germination number, biomass and plant height of seedlings of two reproductive modes. Then, through the control experiment “The influence of environmental factors on S.angustifolium sexual reproduction”, we found that: water level, temperature and distribution depth have great influence on the germination rate of S.angustifolium seeds, among which the fluctuation of water level and temperature in different degrees are beneficial to germination, while the distribution depth is negatively correlated with germination, while the nutritional gradient has no significant effect on the germination rate of seeds. The second part of this paper focuses on the plastic response of S.angustifolium to environmental disturbances during their growth period. Firstly, the field survey showed that, with the change of time, submerged life style increased their investment in the underground part in the two water forms of natural environment (running water and standing water), but their total biomass was lower than that of emergent life style. With the increase of water level, both submerged and emergent life style not only increase the allocation of underground resources, but also significantly increase the plant height. In the same water depth, the plant height and belowground biomass of emergent life style are higher than those of submerged life style. Although the number of clonal ramets of submerged life style decreased with water depth, it was significantly more than that of emergent life style. Then, two experiments were carried out, “The growth performance of S.angustifolium in different heterogeneous soil type and water depth environments” and “The clonal plasticity of plants in different hydrological habitats”: compared with the homogeneous soil nutrient substrate, the heterogeneous soil nutrient substrate did not play a positive role in plant growth, and the biomass accumulation of S.angustifolium in the two heterogeneous substrate was significantly different. When S.angustifolium are stressed by high water level, they will invest more in the aboveground parts to obtain light resources. Sexual reproduction is blocked at high water level, and asexual reproduction is still the main reproductive mode. Compared with standing water, S.angustifolium in running water produce more ramets and longer stolons, and form streamlined leaves. These morphological structures can alleviate the pressure of water flow. Moreover, S.angustifolium increase the allocation of underground resources (biomass, clonal ramets, etc.) and these plasticity improves the fixation ability of plants in running water habitats. Two experiments “The reproductive strategies of S.angustifolium to simulate temperature rise and water level gradient” and “The resistance strategies of plant populations to invasive species” were carried out to find out: with the increase of water level, plant height was significantly affected; however, under warming conditions, its asexual reproduction dominated, the number of clonal ramets and the investment of biomass in each part of clonal ramets increased, whereas the seed biomass of sexual reproduction gradually decreased. Under low water level, compared with submerged and emergent invasive plants, floating invasive plants (Eichhornia crassipes and Pistia stratiotes) have a significant impact on plant growth and reproduction by occupying the upper niche of the water body. Therefore, S.angustifolium mainly capture light and nutrient resources through clonal growth in horizontal direction, and plant populations have strong resistance to invasive plants of other two life forms. In conclusion, different environmental factors, biological factors and species characteristics determine that S.angustifolium show different reproductive patterns and morphological characteristics in the face of habitat heterogeneity. In the face of environmental disturbance, plant growth and reproduction strategies are mainly produced by increasing the proportion of asexual reproduction and adjusting the proportion of biomass allocation. Key words: Environmental heterogeneity; Reproductive strategy; Resource allocation; Morphological plasticity; S.angustifolium.