不同品种藜麦幼苗对干旱胁迫的生理响应及耐旱性评价

Evaluation of drought tolerance and physiological response to drought stress of different varieties of quinoa seedlings

为研究干旱胁迫对不同品种藜麦幼苗生长和生理特性的影响并评价不同品种耐旱性,本试验以4个陇藜系列藜麦品种(即‘陇藜1号’、‘陇藜2号’、‘陇藜3号’和‘陇藜4号’)为材料,设置正常灌水(CK)、轻度水分胁迫(LD,土壤含水量为田间持水量的60%~50%)、中度水分胁迫(MD,土壤含水量为田间持水量的40%~30%)和重度水分胁迫(SD,土壤含水量为田间持水量的20%~10%)4个处理,通过测定幼苗生物量指标和生理生化指标,运用数学分析方法明确测定指标与干旱胁迫的关系,并进行耐旱性评价。结果表明:SD处理各品种幼苗株高分别较CK降低了30.64%、28.36%、32.76%和37.88%,根长分别较CK增加了37.54%、81.46%、43.33%和74.85%,根冠比较CK分别升高了42.86%、33.33%、40.00%和40.00%;‘陇藜1号’幼苗叶片叶绿素含量分别较CK处理升高了29.40%,其余3个品种分别较CK处理降低了33.22%、36.20%和15.99%;各供试品种幼苗叶片可溶性糖含量较CK处理分别升高了0.51%、1.67%、1.19%和2.07%;脯氨酸含量较CK处理分别升高了116.84%、268.07%、798.01%和208.70%;‘陇藜3号’幼苗叶片SOD活性较CK处理升高了6.67%;各供试品种幼苗叶片POD活性较正常处理分别升高了163.96%、62.83%、73.27%和169.50%;幼苗叶片CAT活性较CK处理分别升高了16.87%、11.44%、10.79%和4.30%。说明干旱胁迫下,藜麦幼苗通过增加渗透调节物质含量、增强抗氧化酶活性、清除体内活性氧物质,从而使幼苗适应干旱环境;但当干旱胁迫严重到一定程度时,抗氧化酶活性减弱,植株体内ROS积累,叶片叶绿素合成和干物质积累受到抑制,表现为植株生长受到影响。通过隶属函数法分析可知,供试材料抗旱性表现为‘陇藜1号’=‘陇藜3号’>‘陇藜2号’>‘陇藜4号’。

The purpose of this study was to evaluatethe drought stress on seedling growth and physiological characteristics of different quinoa varieties and their drought resistance.The experiment used four quinoa varieties as materials.Four drought different treatments were normal irrigation(CK),light drought stress(LD,soil moisture content 60%~50%of field capacity),moderate drought stress(MD,soil moisture content 40%~30%of field capacity),and severe drought stress(SD,soil moisture content 20%~10%of field capacity).Plant height,root length,root-shoot ratio,chlorophyll,soluble sugar,soluble protein,proline,MDA content,O—·2 production rate,antioxidant enzyme activity and other physiological and biochemical indicators were measured.The relationship between indicators and drought stress was calculated by correlation analysis and principal component analysis,and the drought tolerance of 4 tested varieties was evaluated by membership function method.The results showed that compared with CK,the plant height of four quinoa varieties was decreased by 30.64%,28.36%,32.76%and 37.88%,root length was increased by 37.54%,81.46%,43.33%and 74.85%,and R/C ratio was increased by 42.86%,33.33%,40.00%and 40.00%under SD treatment,respetively.The chlorophyll content of‘Longli No.1’was increased by 29.40%than CK,and the other varieties were decreased by 33.22%,36.20%,15.99%,respetively.The soluble sugar content was increased by 0.51%,1.67%,1.19%and 2.07%,and proline content was increased by 116.84%,268.07%,798.01%and 208.70%,SOD activity of‘Longli No.3’was increased by 6.67%than CK.POD activity was increased by 163.96%,62.83%,73.27%and 169.50%,and CAT activity was increased by 16.87%,11.44%,10.79%and 4.30%under SD treatment,respectively.The findings indicated that under drought stress,the activity of antioxidant enzymes of plant was enhanced,and osmotic regulating substances were accumulated to eliminate ROS in the body,so as to adapt to the drought environment.However,when drought stress reached to high degree,the activity of antioxidant enzyme was weakened,ROS was accumulated,and chlorophyll synthesis was inhibited,so plant growth was affected.Based on the analysis of subordination function method,the order of drought resistance(from strong to weak)of the 4 tested varieties was‘LongLi No.1’=‘LongLi No.3’>‘LongLi No.2’>‘LongLi No.4’.