PEG胁迫下玉米自交系苗期抗旱性鉴定及评价

在人工气候室利用水培试验,对17个玉米自交系进行苗期PEG胁迫,测定对照(正常水分)与PEG胁迫处理的叶片相对含水量、叶绿素荧光参数、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、脯氨酸(Pro)含量及单株干质量,并采用模糊隶属函数和聚类分析方法对17个玉米自交系进行抗旱性评价和分类,以期筛选出苗期抗旱的玉米种质,建立抗旱性评价体系。结果表明,与对照相比,PEG胁迫下,除PSⅡ最大光化学量子产量Fv/Fm外,其他指标均发生显著变化,表现为叶片相对含水量下降,SOD和POD活性、Pro含量增加,单株干质量增加,说明玉米通过增加Pro含量、提高SOD和POD活性来应对干旱胁迫;同时,PEG胁迫下玉米自交系间的所有指标差异总体均达到了显著水平。隶属函数抗旱性评价与聚类分析将郑7024、郑588、L269、吉853归为中抗旱型玉米自交系,其他自交系均归为弱抗旱型玉米自交系。

Identification and Evaluation of Drought Resistance of Maize Inbred Lines at Seedling Stage under PEG Stress

Seventeen maize inbred lines were treated by PEG stress at seedling stage by hydroponic experiments in artificial climate chamber,and leaf relative water content,fluorescence parameters,the activities of SOD,POD,Pro content and plant dry matter weight were determined between control(normal water culture) and PEG stress treatments,the drought resistance identification and classification of 17 inbred lines were done by membership function and clustering analysis method to select seedling drought resistance germplasms,establish drought resistance evaluation system.The results showed that under PEG stress condition,almost all indexes showed a marked change except the PS Ⅱ maximum photochemical quantum Fv/Fm compared to control,leaf relative water content decreased,SOD and POD activities,Pro content increased,the plant dry weight increased,indicating that maize could respond to PEG drought stress by increasing Pro content,the activities of SOD and POD;at the same time,physiological and biochemical indexes reached a significant level among inbred lines under PEG stress condition.Zheng 7024,Zheng 588,L269 and Ji 853 were classified as middle resistant inbred lines,other inbred lines were classified as weak drought resistant inbred lines type by membership function evaluation of drought resistance and the clustering analysis.