Purpose To cope with the low temperature and rainy weather of flue-cured tobacco transplanting period in the paddy-tobacco growing area in southern Hunan, promoting the early growth and rapid development of flue-cured tobacco.
Methods Pot experiments were conducted to study the effects of applying humic acid fertilizer (all-round organic carbon fertilizer) to the above-ground growth, root growth, dry matter accumulation and distribution, leaf SPAD value, nitrate reductase (NR) activity, malondialdehyde content and antioxidant enzyme activity of tobacco seedlings under low temperature stress.
Results Mass concentration of humic acid fertilizer had double effects on the growth and development of flue-cured tobacco under low temperature stress, showing low mass concentration promoted and high mass concentration inhibited. Proper application of humic acid fertilizer (417-833 mg per plant) could alleviate the damage of low temperature stress, promoting the growth of root and shoot, the accumulation of dry matter, and the root activity of tobacco seedlings; the SPAD value of leaves was increased by 4.64%-5.80%, superoxide dismutase (SOD) activity was increased by 23.20%-50.26%, catalase (CAT) activity was increased by 5.39%-9.54%, and peroxidase (POD) activity was increased by 137.29%-151.43%. At the same time, it could improve the recovery growth ability of tobacco seedlings after low temperature stress, the SPAD value of leaves increased by 7.87%-10.64%, the NR activity increased by 30.30%-42.42%, the CAT activity increased by 0.89%-26.72%, and the POD activity increased by 90.91%-145.45%.
Conclusion The application of humic acid fertilizer can improve the cold resistance and growth recovery of tobacco seedlings, doing benefit to the early growth and rapid development of tobacco seedlings in southern paddy-tobacco growing area.
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