干旱胁迫下腐植酸对燕麦叶片光合性能的调控效应

为明确腐植酸在干旱胁迫下对燕麦叶片光合性能的调控效应,以燕麦品种燕科二号为试验材料,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个水分条件喷施腐植酸和等量清水(CK),分析了干旱胁迫下喷施腐植酸后燕麦叶片光合色素含量、光合特性、干物质积累及产量的变化。结果表明,随着土壤水分的减少,燕麦叶片的叶绿素a含量、叶绿素b含量、类胡萝卜素含量、光合速率、气孔导度、蒸腾速率、胞间CO_2浓度、干物质积累量、产量及其构成因素均呈下降趋势。在正常供水条件下,喷施HA处理的各指标值与CK差异不显著;干旱胁迫下,与CK相比,喷施腐殖酸后各指标值均不同程度提高,其中在重度干旱胁迫下提高幅度较大,且差异均达到显著水平。由此说明,干旱胁迫条件下喷施腐植酸可改善燕麦叶片的光合性能,促进干物质积累和增加产量,且在重度干旱胁迫条件下效果最明显。

Effect of Spraying Humic Acid on Photosynthetic Characteristics of Oat Leaves under Drought Stress

In order to clarify the regulation effect of humic acid (HA) on the photosynthetic characteristics of oat leaves under drought stress,the oat variety Yanke 2 was used as the experimental material,and the pot water was used to set normal water supply (75% field water holding capacity) and moderate drought stress (60% field water holding capacity and severe drought stress (45% field water holding capacity). HA and equal water (CK) were sprayed under three water conditions. Changes in photosynthetic pigment content,photosynthetic characteristics,dry matter accumulation and yield of oat leaves were analyzed. The results showed that with the decrease of soil moisture,chlorophyll a content,chlorophyll b content,carotenoid content,photosynthetic rate,stomatal conductance,the transpiration rate,intercellular CO₂ concentration,dry matter accumulation,yield and its components all showed a downward trend. The differences of index values between normal water supply conditions and spraying HA under drought stress was not significant. Under drought stress,compared with CK,the indices increased after spraying HA,and the increase was significant under severe drought stress. This indicates that spraying HA under drought stress improved the photosynthetic performance of oat leaves,promoted dry matter accumulation and increased yield,with a most obvious effect under severe drought stress.