干旱胁迫下腐植酸对燕麦叶片非结构性碳水化合物代谢的影响

Effects of Humic Acid on Metabolism of Non-structural Carbohydrates in Oat Leaves under Drought Stress

以燕麦品种‘燕科2号’为试验材料,采用盆栽方式,分别在正常供水(75%田间持水量)、中度干旱胁迫(60%田间持水量)和重度干旱胁迫(45%田间持水量)3个水分条件下喷施腐植酸(HA)和等量清水(CK),对燕麦叶片中非结构性碳水化合物(NSC)含量及相关酶活性和籽粒产量进行测定,以明确腐植酸在干旱胁迫下对燕麦叶片非结构性碳水化合物代谢变化的影响,探讨HA对燕麦耐旱性的影响及其作用机制。结果表明:(1)随着土壤水分含量的减少,燕麦叶片中蔗糖和淀粉含量逐渐显著降低,蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)活性显著降低,而酸性转化酶(S-AI)和淀粉水解酶(α-GC)活性显著提高。(2)燕麦叶片可溶性总糖和还原糖含量随着土壤水分含量的减少表现出先升高后降低的变化趋势,导致籽粒产量显著下降,且干旱胁迫程度越重变化幅度越大。(3)叶面喷施HA能不同程度提升中度和重度干旱胁迫下燕麦叶片中上述非结构性碳水化合物含量,并调节相关酶活性,显著提高籽粒产量,并在重度胁迫下的效果更佳。研究发现,腐植酸可以通过调控燕麦叶片NSC的代谢来响应干旱胁迫,降低叶片细胞渗透势,有效缓解干旱胁迫造成的损伤,增强植株耐旱性。

The oat variety‘Yanke 2’was used as the experimental material,and potted plants were used in normal water supply(75%field water holding capacity),moderate drought stress(60%field water holding capacity)and severe drought stress(45%field water holding capacity).Spraying humic acid(HA)and the same amount of water(CK)under 3 water conditions,we determined the content of non-structural carbohydrates(NSC)in oat leaves,related enzyme activities and grain yield.The effect of HA on the drought tolerance of oats and its mechanism were preliminarily discussed on the changes of non-structural carbohydrate metabolism in oat leaves.The results showed that:(1)with the decrease of soil moisture content,the sucrose and starch contents in oat leaves gradually decreased significantly,and the activities of sucrose synthase(SS)and sucrose phosphate synthase(SPS)decreased significantly,while the activities of acid invertase(S-AI)and amylolytic enzyme(α-GC)increased significantly.(2)The contents of total soluble sugar and reducing sugar in leaves showed a trend of increasing first and then decreasing,leading to a significant decrease in grain yield,and the heavier the drought stress,the greater the decrease.(3)Foliar spraying of HA can increase non-structural carbohydrate content in oat leaves under moderate and severe drought stress to varying degrees,regulate related enzyme activities,significantly increase grain yield,and have a better effect under severe stress.Studies have found that humic acid can respond to drought stress by regulating the metabolism of oat leaf NSC,reducing leaf cell osmotic potential,effectively alleviating the damage caused by drought stress,and enhancing plant drought tolerance.