谷子苗期对不同干旱胁迫的生理响应

Physiological Responses of Foxtail Millet to Different Drought Stress at Seedling Stage

采用聚乙二醇(Polyethylene glycol,PEG)溶液模拟干旱环境,对谷子种质资源进行室内萌发期抗旱性鉴定评价,旨在筛选出具有抗旱特性的优质品种。以冀谷37和冀谷38抗逆谷子品种为试验材料,并以华北夏谷区域广适性品种豫谷18作为对照,采用不同浓度PEG对其进行干旱胁迫处理,并对处理7 d后幼叶的丙二醛、甜菜碱、游离脯氨酸、叶绿素含量以及超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化物酶(Peroxidase,POD)活性进行检测。结果表明,与对照品种豫谷18相比,冀谷37和冀谷38在中度和重度干旱胁迫(12%PEG、18%PEG)下丙二醛含量显著降低;冀谷38在中度和重度干旱胁迫下渗透调节物质游离脯氨酸含量显著增加,冀谷37和冀谷38甜菜碱含量均显著增加;冀谷38 SOD活性显著增强,但冀谷37仅在轻度和重度干旱胁迫(6%PEG、18%PEG)SOD活性高于豫谷18;冀谷37和冀谷38的POD活性在重度干旱胁迫下显著降低;冀谷38叶绿素含量均显著增加,但冀谷37仅在轻度和中度胁迫(6%PEG、12%PEG)下叶绿素含量显著增加。综上,冀谷37和冀谷38在幼苗期具有较强的耐旱能力,耐旱性优于对照品种豫谷18,且冀谷38抗旱能力强于冀谷37。

Polyethylene glycol(PEG)solution was used to simulate drought conditions for the identification and evaluation of drought resistance of foxtail millet germplasm resources during the indoor germination stage.This process aimed to screen for high-quality cultivars with drought resistance.In this experiment,two drought-resistant foxtail millet cultivars,Jigu 37 and Jigu 38,were utilized as the tested materials,and Yugu 18,a widely adaptable cultivar in the north China summer foxtail millet region,was taken as the control.Different concentrations of PEG were used to impose drought stress,and after 7 days of stress,the contents of chlorophyll(Chl),betaine,free proline(Pro),malondialdehyde(MDA),and the activities of superoxide dismutase(SOD)and peroxidase(POD)in the young leaves were measured.The results indicated that,compared to the control cultivar Yugu 18,Jigu 37 and Jigu 38 exhibited significantly reduced malondialdehyde content under moderate and severe drought stress(12%and 18%PEG),Jigu 38 had significant increase in osmotic regulation substance,free proline,content under moderate and severe drought stress,both Jigu 37 and Jigu 38 had significant increase in betaine content.Jigu 38 possessed significantly enhanced SOD activity,but the SOD activity of Jigu 37 was only significantly higher than that of Yugu 18 under mild and severe drought stress(6%and 18%PEG).The POD activity of Jigu 37 and Jigu 38 was significantly reduced under severe drought stress.Jigu 38 exhibited significantly enhanced chlorophyll content,while,Jigu 37 only exhibited significantly enhanced chlorophyll content under mild and moderate drought stress(6%and 12%PEG).Comprehensive analysis of multiple physiological indexes showed that Jigu 37 and Jigu 38 had stronger drought resistance at the seedling stage,they were superior to Yugu 18 on drought resistance,and the drought resistance of Jigu 38 was better than that of Jigu 37.