Research Center of Aquatic Organism Conservation and Water Ecosystem Restoration in University of Anhui Province, Anqing Normal University, Anqing, 246011, China.
Center for Watershed Ecology, Institute of Life Science and School of Life Science, Nanchang University, Nanchang, 330000, China.
Environ Sci Pollut Res Int. 2018 Dec;25(34):34583-34594. doi: 10.1007/s11356-018-3429-5. Epub 2018 Oct 12.
Plant roots in lakeshore areas can directly determine the survival of the aboveground plant parts. However, most current studies are focused on the aerial shoots, and less attention has been paid to the functions of the roots. In order to evaluate the effects of water level fluctuations (WLFs) on root architectural and morphological traits of plants in lakeshore areas, field investigations were conducted seasonally in three subtropical floodplain lakes with different types of WLFs. The results showed that both the pH and moisture contents of the soils were significantly different in all seasons among the three lakes, while the total nitrogen and total phosphorus in the soils only showed significant differences in certain seasons. Significant differences were also found in the two architectural trait parameters (root length density and root branching number) and three morphological trait parameters (root tissue density, root surface area, and root volume), all of which (except for root tissue density) were highest in the Dahuchi lake that experiences intermittent WLFs, and lowest in the Chaohu Lake with reservoir-like WLFs. With increasing lakeshore elevation gradients, we found that root length density, root branching number, root surface area, and root volume in the three lakes changed significantly, and all these root trait parameters increased first and then decreased. However, no significant differences were found for the above four root traits in the three lakes over the different seasons. Spearman correlation analyses indicated that both the hydrological and physicochemical factors were strongly correlated with the architectural and morphological root trait parameters, and the duration of submergence (duration) was the most important factor, judging from the correlation coefficients (R). The results of stepwise multiple regression further indicated the duration was the key factor affecting plant root traits. Based on the results of this study, we suggest that the WLFs in reservoir-like lakes should be changed in order to improve the ecological functions of the lakeshore.
湖滨地区的植物根系可以直接决定地上部分植物的存活。然而，目前大多数研究都集中在地上部分，而对根系的功能关注较少。为了评估水位波动（WLFs）对湖滨地区植物根系结构和形态特征的影响，我们在三个具有不同 WLF 类型的亚热带洪泛区进行了季节性实地调查。结果表明，三个湖泊的土壤 pH 值和水分含量在所有季节都有显著差异，而土壤中的总氮和总磷仅在某些季节存在显著差异。两个结构特征参数（根长密度和根分枝数）和三个形态特征参数（根组织密度、根表面积和根体积）也存在显著差异，所有这些参数（除根组织密度外）在经历间歇性 WLFs 的大湖最高，在具有水库式 WLFs 的巢湖最低。随着湖滨高程梯度的增加，我们发现三个湖泊的根长密度、根分枝数、根表面积和根体积都发生了显著变化，所有这些根系特征参数都是先增加后减少。然而，在三个湖泊中，不同季节的上述四个根系特征并没有显著差异。Spearman 相关分析表明，水文和物理化学因素与根系结构和形态特征参数密切相关，其中淹没时间（duration）是最重要的因素，从相关系数（R）可以看出。逐步多元回归的结果进一步表明，持续时间是影响植物根系特征的关键因素。基于本研究的结果，我们建议改变水库式湖泊的 WLFs，以提高湖滨的生态功能。
