沙漠先锋植物沙米(Agriophyllum squarrosum)生活史对策对降水格局的响应  

Responses of life history strategies of pioneering desert plant Agriophyllum squarrosum to precipitation patterns

作　　者：刘美玲 李新荣[3] 谢惠春 毛晓宁[1] 杜少波 朱瑞清 LIU Meiling;LI Xinrong;XIE Huichun;MAO Xiaoning;DU Shaobo;ZHU Ruiqing(Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau,College of Life Science,Qinghai Normal University,Xining 810000,China;Academy of Plateau Science and Sustainability,Qinghai Normal university,Xining 810000,China;Shapotou Desert Research&Experiment Station,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Qinghai Forest Ecosystem Observation and Research Station in the Southern Qilian Mountains,Huzhu 810500,Qinghai,China)

机构地区：[1]青海师范大学生命科学学院,青海省青藏高原药用动植物资源重点实验室,西宁810000 [2]青海师范大学高原科学与可持续发展研究院,西宁810000 [3]中国科学院西北资源环境生态研究院,沙坡头沙漠研究试验站,兰州730000 [4]青海祁连山南坡森林生态系统国家定位观测研究站,青海互助810500

出　　处：《生态学杂志》2023年第4期820-827,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31600332);甘肃省科技厅一般项目(20JR10RA027);青海省科技厅项目(2020-NK-125)资助。

摘　　要：沙米(Agriophyllum squarrosum)是流动沙丘恢复过程中的先锋物种。然而,对于沙米如何适应流动沙丘这一特殊的生境,全球变化背景下沙米的生活史对策如何响应降水格局的变化,研究还相对匮乏。本研究采集流动沙丘不同部位的沙米种子库,分析了种子库的垂直分布特征;并且在腾格里沙漠东南缘,观测了3个年份(2017—2019年)的降雨模式对种群动态及繁殖特征的影响,进而阐述沙米的生活史对策对降水格局的响应。结果表明,沙米种子库主要分布在20~60 cm深度的土层中。3个年份不同降雨模式下的田间种群动态表明,沙米的萌发、存活和死亡对降雨变化极为敏感。持续稳定的降水模式(2018年)更有利于沙米种群的数量稳定增加并顺利完成生活史,实现种群的延续;而随机性较强的降水格局(2019)容易造成幼苗的大量死亡,不利于种群的生存及延续。2018年在持续稳定的降水格局下,沙米顺利完成其生活史,并进行更高的繁殖分配,使沙米产生更多、更大的种子,实现种群的繁衍。而降水波动性及不确定性最大的2019年,产生的种子数量较少,种子千粒重也较小。本研究表明,降水是决定沙米种群数量的关键因素。沙米种子库的垂直分布异质性,赋予其休眠特征,这对于沙米种群的存续至关重要。萌发策略呈现为机会主义萌发特征,有利于沙米对沙漠生境不确定性较强且数量稀少的降水的有效利用;繁殖策略倾向于利用持续稳定的降水产生更高的繁殖分配,实现种群的繁衍。沙米生活史对策对降水格局响应敏感,在其适应沙区稀少且极强的不确定性降水环境中发挥着重要的作用。Agriophyllum squarrosum is a pioneer species in mobile dunes.However,little is known about how A.squarrosum adapts to the habitats of mobile dunes,and in particular,how its life history strategies respond to the changes of precipitation pattern under global climate change.In this study,we investigated the vertical distribution of A.squarrosum seed banks in different parts of mobile dunes at the southeastern edge of the Tengger Desert,and examined the effects of rainfall patterns on population dynamics,reproductive characteristics,and life history strategies of A.squarrosum during 2017-2019.The results showed that seed bank density was mainly concentrated in the 20-60 cm soil layer.The germination,survival and death of A.squarrosum were sensitive to rainfall changes.A continuous and stable precipitation pattern in 2018 favored a steady population increase and life cycle completion,which is beneficial for A.squarrosum to produce larger seeds and to realize its population reproduction.However,a more random precipitation pattern(with high fluctuation and uncertainty)in 2019 caused massive seedling mortality,smaller seed production,and lighter seed mass,which is harmful to its population survival and continuation.Precipitation is a key factor determining the population size of A.squarrosum.The vertical distribution heterogeneity of seed bank endows it with dormancy characteristics,which is crucial for the population survival.The opportunism germinating strategy of A.squarrosum is beneficial for the effective utilization of scarce precipitation with great uncertainty in desert habitats.Reproductive strategies tend to use sustained and stable precipitation to produce higher reproductive allocation.Life history strategies of A.squarrosum are sensitive to precipitation patterns and play an important role in adapting to the environment with extremely uncertain and rare precipitation.

关 键 词：沙米 种子库 降水格局 种群动态 繁殖特征 

分 类 号：Q948[生物学—植物学]