榆中北山弃耕地五种不同演替阶段的植物种子根特征比较  

The comparation of seminal root traits of five successional species in abandoned arable land in northern mountainous regions of Yuzhong County

作　　者：于明茜 方向文[1] 姚广前 赵伟男[1] 毕敏慧 

机构地区：[1]兰州大学,生命科学学院,草地农业生态系统国家重点实验室,兰州730000

出　　处：《生态学报》2015年第10期3252-3257,共6页Acta Ecologica Sinica

基　　金：教育部新世纪优秀人才支持计划(NCET-11-0207);国家自然科学基金(31070354,31370423);兰州大学中央高校基本科研业务费专项资金资助(860995)

摘　　要：用凝胶根系观测装置对榆中北山弃耕地演替前期的黄花蒿,中期的阿尔泰狗娃花、冷蒿、赖草和后期的短花针茅的种子根生长进行了为期2周的观测,比较了种间种子根特征以及种子根特征与千粒重之间的关系。结果表明演替前期的黄花蒿萌发起始时间为6 d,中期的阿尔泰狗娃花、冷蒿、赖草为6—9 d,后期的短花针茅为14 d。演替前期的黄花蒿主根较短,但侧根数较多,侧根较长,侧根生长速率较高,侧根总长与主根长比率较大,主侧根夹角较大;演替后期的短花针茅主根较长,但侧根数少,侧根短,侧根生长速率小,侧根总长与主根长比率低,主侧根夹角小;演替中期的阿尔泰狗娃花、冷蒿、赖草的上述各指标值介于黄花蒿和短花针茅之间。主根长、侧根数、侧根总长、主侧根夹角与植物种子千粒重之间不存在相关关系。结果表明从演替前期到演替后期,植物种子根投入向增加主根生长,减少侧根生长的方向演变,这是不同演替阶段的植物对演替过程中土壤逐渐旱化长期适应的结果。Soil water content decrease gradually from early-successional habitats to late-successional habitats in abandoned arable land in northern mountainous region of Yuzhong County. Accordingly, late-successional species have stronger ability to resist drought stress than early-successional species. Root traits are associated with plant drought resistance, and therefore, it is proposed that root traits between early-successional species and late-successional species should differ significantly. However, relatively little effort has been focused on the investigation of root traits among successional species. The object of this study is to use simple gel chamber to compare seminal root straits in early-successional species, Arternsia annua, middle-successional species, Heteropappus altaicus, Artemisia frigida, and Leymus seealinus, and late-successional species, Stipa Breviflora. Seeds germinated on the surface of gel in petri dishes, oriented vertically so that the radicles faced downwards, at 16 ~C/8 ~C day/night. After germination, seeds were transferred to the gel chambers, maintaining the same orientation as during germination, and allowed seminal root to grow at temperature mentioned above. Measured parameters included main root length, main root elongation rate, lateral root number, lateral root length, lateral root elongation rate, the ratio of lateral root length to main root length, angular between main and lateral roots and thousand-seed weight. The results showed that germination time for early-successional species was about 6 days, for middle-successional species ranged from 6 days to 9 days, and for late-successional species was about 14 days. After 2-week growth, early-successional specie, A. annua, had short main root, an increase in lateral root number, lateral root length and lateral root elongation rate, an increase in the ratio of lateral root length to main root length, and high angular between main and lateral roots. By contrast, late-successional species, S. Breviflora, had an increase in main root

关 键 词：种子根 长度 生长速率 侧根数 主侧根夹角 

分 类 号：Q944.54[生物学—植物学]