关键词: 水稻幼苗, 壳寡糖, 非生物胁迫, 抗逆性, 生长

Abstract: The effects of low temperature, drought, and salt stress on the growth and resistance of rice seedlings were studied by spraying different concentrations of oligochitosan with the molecular weight of 2 000-3 000. The rice seedlings were divided into one normal control group and eight treatment groups. The treatment groups were sprayed with 0, 12.5, 25, 50, 125, 250 and 500 mg/L oligochitosan, respectively, the leaf samples were collected regularly, and then the physiological indicators were determined.The results indicated that the groups sprayed with 25 and 50 mg/L oligochitosan showed lower relative conductance in seedlings under low temperature stress.The leaf relative conductance decreased significantly after return to normal growth for 24 h. After the rice seedlings restored growth by low temperature stress for 72 h, its stem height increased significantly by 19.85% and 24.4%, respectively; and the main root length of it increased significantly by 49.50% and 42.3%, respectively.After return to normal growth for 24 h, the malondialdehyde(MDA) content in the treatment group sprayed with 50 mg/L oligochitosan was decreased significantly. By analyzing the leaf relative conductance, the results showed the rice seedlings were greatly affected by the drought and salt stress. The damage of drought stress to rice leaves could be decreased when the concentration of oligochitosan was 12.5, 25, 50 and 125 mg/L.Moreover, the negative effect of salt stress could be alleviated through spraying with 25 and 50 mg/L oligochitosan. In conclusion, not only the stress resistance, but also the growth of rice seedlings was improved by appropriate concentrations of oligochitosan.

Key words: rice seedlings, oligochitosan, abiotic stress, stress resistance, growth