Alleviation Effects of Exogenous Trehalose and Choline Chloride on the Seedlings of Rapeseed under Drought Stress

PurposeTo study the technology and mechanism of improving drought tolerance of rape seedling under drought stress.

MethodTen rapeseed varieties were used to study the effects of exogenous substances (trehalose and choline chloride) on the growth and physiological characteristics of rapeseed under drought stress. The drought tolerance of these varieties and the comprehensive mitigation effects of different exogenous substances were subsequently evaluated and compared.

ResultThe plant height, root length, total dry weight, total fresh weight, root dry weight, root fresh weight, aboveground dry weight, aboveground fresh weight, soluble protein content and superoxide dismutase (SOD) activity significantly decreased (P<0.05), while proline, soluble sugar, malondialdehyde (MDA) contents and peroxidase (POD) activity significantly increased under drought stress (P<0.05). The addition of exogenous substances could effectively alleviate the decline of morphological and biomass indexes, significantly increase SOD activity and soluble protein content (P<0.05), and significantly reduce MDA, proline and soluble sugar contents (P<0.05). Except for plant height, root length, soluble sugar content, MDA content and CAT activity which was insignificant difference between two exogenous treatment, the remaining 10 indicators exhibited superior alleviating drought injury with trehalose than with choline chloride (P<0.05). The comprehensive evaluation of drought tolerance showed that Qinyou 10 and Youwang 999 (comprehensive evaluation value: E=0.480-0.532) were the most drought-resistant types; Fengyou 737, Qinyou 33, Qinyou 19, Huaxiangyou 11, Kaiyu 09 were types of medium drought-resistance (E=0.286-0.371); and Qinyan 211, Huaiyou 18 and Nannongyou 3 were drought-sensitive types (E=0.199-0.222). The alleviated effect of trehalose (the average increase of E value was 32.70%) was more effective than that of choline chloride (13.57%).

ConclusionThis study suggested that trehalose could relieve the drought injuries better in seedling stage, laying a foundation for improving drought resistant cultivation of rapeseed.