PEG模拟干旱胁迫下玉米胚芽鞘长与其抗旱性的关系分析

以6份抗旱性不同的玉米自交系为试材,用不同浓度的PEG-6000(polyethylene glycol,PEG)渗透溶液进行模拟干旱胁迫处理,分析玉米萌芽期中胚轴长、胚芽鞘长及苗长的变化,并将其与田间干旱胁迫处理下相应玉米自交系产量及产量相关性状的抗旱指数进行相关分析,以期揭示萌芽期玉米幼苗相关性状与其抗旱性的关系。结果表明:(1)萌芽期随着PEG浓度增加,玉米自交系胚芽鞘长、中胚轴长及苗长都呈下降趋势,其中苗长降低幅度最大,平均降幅为14%,中胚轴长次之,平均降幅为11%;(2)方差分析表明,不同玉米自交系幼苗的中胚轴长、胚芽鞘长在自交系间及PEG浓度间差异极显著,苗长在PEG浓度间差异极显著;(3)花期田间干旱胁迫下,各玉米自交系的千粒重、穗粒数及产量较正常灌溉明显下降,且其平均降幅分别为8%、14%、13%;(4)通过玉米田间产量及产量相关性状抗旱指数与萌芽期各性状相关性分析表明,中胚轴长与千粒重、穗粒数及产量的抗旱指数呈显著或极显著正相关。胚芽鞘长与千粒重、穗粒数及产量的抗旱指数呈极显著正相关,而在5%的PEG-6000渗透溶液模拟干旱胁迫下,胚芽鞘长与千粒重抗旱指数相关系数最高为0.832。因此,胚芽鞘较长的自交系其抗旱性较强,胚芽鞘长度可作为玉米早期抗旱性筛选的重要指标。

Analysis of the Relationship between Coleoptile Length and Drought Resistance under PEG Simulated Drought Stress in Maize

The six different drought tolerant inbred lines in maize were used to analyze the changes of mesocotyl length,coleoptile length and seedling length at germination stage under different concentrations of PEG-6000(polyethylene glycol,PEG)permeate solution,analyze the correlation between the drought resistance index of yield and yield-related traits under field drought stress treatment and these corresponding traits at germination stage,and then to reveal the relationship between the corresponding traits of maize seedlings at germination stage and their drought resistance.The results showed that:(1)At germination stage,with the concentration of PEG increased,the length of coleoptiles,mesocotyl and seedlings of maize inbred lines showed a downward trend.Among them,the seedling length decreased was the largest,and the average reduction of 14%.The mesocotyl length is secondly,and the average reduction of 11%;(2)Analysis of variance showed that the mesocotyl length and coleoptile length of different maize inbred lines were extremely significantly differences between inbred lines and PEG concentration.The difference in seedling length between PEG concentrations was extremely significant;(3)Flowering period under drought stress in the field.The 1000-grain weight,kernel number and yield of each maize inbred line decreased significantly compared with normal irrigation,and the average reduction of 8%,14%,13%;(4)The correlation analysis between drought resistance index of maize field yield and yield related traits and various traits at germination stage showed that,the mesocotyl length was significantly or extremely significantly positively correlated with 1000-grain weight,kernel number and yield drought resistance index.The coleoptile length was extremely significantly positively correlated with 1000-grain weight,kernel number and yield drought resistance index.Simulated drought stresswith 5%PEG-6000 permeate solution,the correlation coefficient between coleoptile length and 1000-grain weight drought resistance index was 0.832.Therefore,the coleoptile is longer of inbred lines have stronger drought resistance.The length of coleoptile can be used as an important indicator for early drought resistance screening in maize.