Effects of Low Temperature During Booting Stage on Rice Physiology and Alleviating Effect of Exogenous Melatonin.

SHAN Lili

To reveal the influence of low temperature on the seed-setting rate and physiological characteristics, and alleviating effect of exogenous melatonin (MT) on low temperature stress at the booting stage, 2 different cold tolerance rice (Oryza sativa L.) cultivars Longjing 11 (cold sensitive, LJ11) and Longdao 5 (cold tolerant, LD5) were planted for a pot experiment. They were treated with low temperature (16 °C) and 100 μmolµL-1 melatonin (MT) spraying respectively at starching stage, and the same amount of water sprayed at outdoor temperature was used as control. The results showed that under low temperature stress, the seed setting rate of LD5 did not change much, the seed setting rate of LJ11 decreased significantly by 5.96%-45.26%. And in the leaves of both LD5 and LJ11, malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents were significantly increased, superoxide dismutase (SOD) and peroxidase (POD) activities significantly increased. At the same time, low temperature stress could also increase the contents of osmotic regulators. The contents of soluble protein, soluble sugar and proline in the leaves both of LD5 and LJ11 were significantly increased, respectively. Foliar spraying of exogenous MT could effectively alleviate the damage of low temperature to rice, and the effect was more obvious on cold-sensitive varieties. It could significantly reduce the contents of MDA and H2O2, and it could significantly increase SOD and POD activities. In addition, the soluble sugar, soluble protein and proline contents of LJ11 significantly increased. Foliar spraying of exogenous MT could also reduce the effect of low temperature on the seed setting rate, and the seed setting rate of LJ11 significantly increased by 3.13%-16.64%. In conclusion, under low temperature stress, MT could induce the increase of antioxidant enzyme activities and osmotic adjustment substances in rice leaves, and effectively scavenge reactive oxygen species, thereby improving the cold resistance of rice.

LOW temperatures; TEMPERATURE effect; RATE setting; REACTIVE oxygen species; MELATONIN; RICE

Journal of Agricultural Science & Technology (1008-0864), 2023, Vol 25, Issue 9, p23

1008-0864

Academic Journal

10.13304/j.nykjdb.2022.0172