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中国油料作物学报 ›› 2019, Vol. 41 ›› Issue (5): 741-.doi: 10.19802/j.issn.1007-9084.2019025

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Effects of prohexadione-calcium on photosynthetic characteristics and protective enzyme activity of soy?bean seedlings under saline-alkali stress

  

  1. 1. Agronomy College of Heilongjiang Bayi Agricultural University, Daqing 163319,China; 
    2. Agronomy College of Guangdong Ocean University, Zhanjiang 524088,China
  • Online:2019-10-28 Published:2019-12-20

Abstract:

 The aim of this experiment was to study the effects of exogenous EA (prohexadione-calcium) on soy? bean seedlings under saline-alkali stress and to determine the optimum concentration of EA to improve soybean salt-tolerance. Soybean varieties Hefeng 50 and Kenfeng 16 were used as experimental materials, and cultured un? der combined saline-alkali stress of 110 mmol·L-1 for 15 days. Effect of photosynthetic characteristics and protect? ing enzyme activity of soybean were studied by spraying different concentrations of EA in V3 foliar application. Re? sults showed that compared with the control, EA increased chlorophyll a, chlorophyll b, carotenoids, total chloro? phyll content, and decreased chl a/b ratio in leaves of two soybean varieties under saline-alkali stress; increased Pn, Gs, Tr, Ls, WUE and AMC reduced Ci in soybean leaves; significantly increased activity SOD, POD and CAT in soy? bean leaves but the increase of MAD content was inhibited. Comprehensive analysis showed that the best effect was observed when the concentration was 100 mg·L-1, chlorophyll index, net photosynthetic rate and antioxidant enzyme activity increased initially and then decreased with EA concentration, the maximum value appeared at 100 mg·L-1. It was concluded that under saline-alkali stress, exogenous EA could enhance the stability of cell structure, prevent the decline of photosynthetic rate by increasing antioxidant enzyme activity and chlorophyll content of plants and de? creasing MDA content, promote seedling growth and result in becter the tolerance of soybean seedlings to saline-al?
kali stress with the best effect at 100 mg·L-1.

Key words: soybean, saline-alkali stress, prohexadione-calcium, photosynthetic characteristics, protecting enzyme activity