干旱及复水对山西野生草地早熟禾幼苗生长与生理特性的影响

摘要

Research has been undertaken on the effects of drought and rewatering on the growth and physiologi-cal characteristics of 15 species wild Poa pratensis seedlings in Shanxi.Using pot tests,at the four-leaf stage the P .pratensis species were water-controlled for 21 days and then re-watered.Seedling survival rates,relative growth rates (RGR),relative water content (RWC),proline (Pro),and the activity of superoxide dismutase (SOD)and malondialdehyde (MDA)content were measured on the 21st day after water-controlling and the 7th day after rewatering.All indexes were evaluated with the subordination function method to obtain the member-ship value of each population.Results showed that seedling survival rates,RGR,RWC and SOD declined dur-ing the 21-day drought stress.However,Pro and MDA contents increased.After rewatering,all the indexes rehabilitated to some degree but did not recover to the same level as the control groups.Data analysis showed the tested P .pratensis species could be grouped into three kinds.Class Ⅱ were medium drought-resistant pop-ulations,including Qinshui Ⅱ, Hunyuan Ⅰ,Qinshui Ⅰ, Wutai, Hunyuan Ⅱ,Yingxian,Guangling and Lingqiu.Class Ⅲ showed weaker drought resistance,including the Yuanqu,Ningwu,Huozhou,Xinzhou,Wuzhai and Lingshi populations.The Tunliu population was categorized as class Ⅳ,which had no drought re-sistance.The membership value of the QinshuiⅡpopulation was the highest,and could be used as the key se-lection object in the future.%以15份山西野生草地早熟禾种质为材料，待其长至4～5片真叶时，采用盆栽控水法进行21 d 干旱及7 d 复水处理，取样测定植株存活率、相对生长率（RGR）、叶片相对含水量（RWC）、游离脯氨酸（Pro）、超氧化物歧化酶（SOD）和丙二醛（MDA）含量，并根据隶属函数法对其抗旱性进行综合评价。结果表明，在干旱胁迫下，不同居群野生草地早熟禾幼苗的存活率、RGR、RWC 和 SOD 活性下降，Pro、MDA 含量则上升。复水后，各指标均有所恢复，但未能恢复至胁迫前水平。抗旱性综合分析将参试草地早熟禾分为3个类群，其中沁水Ⅱ、浑源Ⅰ、沁水Ⅰ、五台、浑源Ⅱ、应县、广灵和灵丘8个居群为Ⅱ级中等抗旱，垣曲、宁武、霍州、忻州、五寨和灵石6个居群为Ⅲ级弱抗旱，屯留居群为Ⅳ级不抗旱居群。沁水Ⅱ居群的隶属值最大，可作为重点对象进行选育研究。