[Effects of drought stress on the root growth and development and physiological characteristics of peanut]

Taking two peanut varieties Huayu 17 and Tangke 8 as test objects, a soil column culture experiment was conducted in a rainproof tank to study the peanut root morphological development and physiological characteristics at late growth stages under moderate drought and well-watered conditions. Tanke 8 had more developed root system and higher yield and drought coefficient, while Huayu 17 had poorer root adaptability to drought stress. For the two varieties, their root length density and root biomass were mainly distributed in 0-40 cm soil layer, whereas their root traits differed in the same soil layer. The total root length, total root surface area, and total root volume of Huayu 17 at each growth stage were smaller under drought stress than under well-balanced water treatment, while these root characteristics of Tangke 8 under drought stress only decreased at flowering-pegging stage. Drought stress increased the root biomass, surface area, and volume of the two varieties in 20-40 cm soil layer, but decreased these root traits in the soil layers below 40 cm. Under drought stress, the root activity of the two varieties in the soil layers below 40 cm at pod filling stage decreased, and the decrement was larger for Huayu 17. The differences in the root system development and physiological characteristics of the two varieties at late growth stages under drought stress suggested that the root system of the two varieties had different water absorption and utilization under drought stress.