从根系垂向分布认识地下水依赖型植物的干旱适应性——以中国干旱区为例

• 作 者: Tian-Ye Wang Ping Wang Ze-Lin Wang Guo-Yue Niu Jing-Jie Yu Ning Ma Ze-Ning Wu Sergey P.Pozdniakov Deng-Hua Yan
• 机 构: School of Water Conservancy Engineering,Zhengzhou University,Zhengzhou,Henan 450001,China;Key Labora
• 出 处: 植物生态学报（英文版）
• 发表日期: 2021年6期
• 关键词: vertical root distribution root plasticity drought adaptability phreatophytes gr

根系垂向分布是植物与环境相互作用的综合结果.由于对植物细根垂向分布状况及其与环境因素复杂相互作用关系仍缺乏足够认识,导致对气候变化影响下植被动态预测存在很大的不确定性.本研究以柽柳(Tamarix ramosissima)和胡杨(Populus euphratica)两种干旱区河岸带地下水依赖型植物为对象,通过对根系剖面和根系分布数据文献收集整理,并结合根系与环境要素关系等方面,探讨和解析了干旱区植物对干旱环境的适应能力.研究结果表明,柽柳和胡杨两种植物根系具有强向水性(依赖地下水)和灵活的水分利用策略,使得它们可以在极端干旱环境中生存.根系分布特征的差异决定了两种植物发育环境的不同,即柽柳相比胡杨拥有更高的根系可塑性,使其具有更高效的水分利用,从而保证了其在更加复杂多样的气候、土壤等环境条件下生存.地下水依赖型植物根系剖面形态差异大,反映了其具有较强的根系适应能力,从而具有较宽的生态位和较强的生态韧性.因此,在地球系统模式中,亟需发展基于物理过程的根系动态方案,以克服当前模型普遍存在对植物根系塑性刻画不足的问题,从而提升未来气候变化情景下植被响应预测能力.“,”Aims The vertical distribution of plant roots is a comprehensive result of plant adaptation to the environment.Limited knowledge on fine vertical root distributions and complex interactions between roots and environmental variables hinders our ability to reliably predict climatic impacts on vegetation dynamics.This study attempts to understand the drought adaptability of plants in arid areas from the perspective of the relationship between vertical root distribution and surroundings.Methods By analyzing root profiles compiled from published studies,the root vertical profiles of two typical phreatophytes,Tamarix ramosissima and Populus euphratica,and their relationships with environmental factors were investigated.A conceptual model was adopted to link the parameter distribution frequency with plant drought adaptability.Important Findings The strong hydrotropism (groundwater-dependent) and flexible water-use strategy of T.ramosissima and P.euphratica help both species survive in hyperarid climates.The differences in the developmental environments between T.ramosissima and P.euphratica can be explained well by the different distribution characteristics of root profiles.That is,higher root plasticity helps T.ramosissima develop a more efficient water-use strategy and therefore survive in more diverse climatic and soil conditions than P.euphratica.We conclude that the higher variation in root profile characteristics of phreatophytes can have greater root adaptability to the surroundings and thus wider hydrological niches and stronger ecological resilience.The inadequacy of models in describing root plasticity limits the accuracy of predicting the future response of vegetation to climate change,which calls for developing process-based dynamic root schemes in Earth system models.