外源硒调控盐胁迫下小白菜种子萌发特性和生理特性研究

Effect of Selenium on Germination Rate and Physiological Property Under Salt Stress in Pakchoi

以"四季小白菜""京新1号""鲁抗快菜"小白菜种子为试材,采用水培法,研究了NaCl和Na_2SeO_3处理对小白菜种子发芽势、发芽率、发芽指数、活力指数、相对盐害率、耐盐指数、苗长以及丙二醛(MDA)含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响,以探讨不同品种小白菜耐盐性差异并揭示硒元素缓解小白菜盐胁迫的作用效果。结果表明:150mmol·L^(-1)和200mmol·L^(-1) NaCl处理中"四季小白菜"种子的相对盐害率为3.33%和30.00%,"京新1号"种子的相对盐害率为-8.22%和27.4%,"鲁抗快菜"种子的相对盐害率为25.34%和56.36%,表明"鲁抗快菜"耐盐性最弱。同时,150mmol·L^(-1) NaCl处理和1mg·L^(-1) Na_2SeO_3+150mmol·L^(-1) NaCl处理中小白菜种子发芽势、发芽率、发芽指数、活力指数和株高均显著低于对照,但1 mg·L^(-1)Na_2SeO_3+150mmol·L^(-1) NaCl处理中小白菜种子发芽势、发芽率、发芽指数、活力指数和株高较150 mmol·L^(-1) NaCl处理分别提高17.37%、5.52%、5.36%、159.87%和143.91%,相对盐害率降低为8.28%,耐盐指数增加到77.07%。此外,与150mmol·L^(-1)NaCl处理相比,1mg·L^(-1) Na_2SeO_3+150mmol·L^(-1) NaCl处理中小白菜幼苗MDA含量显著降低,POD活性和CAT活性均显著升高,故1mg·L^(-1) Na_2SeO_3能够缓解盐胁迫对小白菜幼苗的毒害。

The current study explored salt tolerance difference of different varieties in pakchoi and illustrated effects of exogenous selenium(Na2SeO3)on germination feature and physiological property under salt stress in pakchoi in order to reveal function of selenium remitting salt stress.‘Four seasons pakchoi’‘Jinxin one’‘Lukang’were cultivated in manual climatic box with 70% humidity and 25℃.The effects of NaCl and selenium on seed germination potential,germination rate,germination index,vigor index,relative salt-harmed rate,salt-tolerance index,seedling length and MDA content,as well as antioxidant enzymes(SOD,POD and CAT)activities were illustrated.The results showed that seed relative salt-harmed rate was 3.33% and 30.00% for‘Four seasons pakchoi’,-8.22% and 27.4%for‘Jinxin one’,25.34% and 56.36% for‘Lukang’in 150 mmol·L^-1 NaCl and 200 mmol·L-1NaCl treatments,respectively.Thus,‘Lukang’had the weakest salt tolerance among selected different varieties in pakchoi.Meanwhile,germination potential,germination rate,germination index,vigor index,salt-tolerance index,and seedling length in 150 mmol·L^-1 NaCl treatment and 1 mg·L^-1Na2SeO3+150mmol·L^-1 NaCl treatments were significant lower than those in control.However,germination potential,germination rate,germination index,vigor index,salt-tolerance index,and seedling length in 1mg·L^-1 Na2SeO3+100mmol·L^-1 NaCl treatment were increased by 17.37%,5.52%,5.36%,159.87% and 143.91%,respectively,in comparison with those in 150 mmol·L^-1NaCl treatment.Relative salt-harmed rate was decreased to 8.28% and salt tolerance index was increased to 77.07%.In addition,MDA content was decreased significantly in 1mg·L^-1 Na2SeO3+150mmol·L^-1 NaCl treatment while POD and CAT activities was increased.Therefore,1mg·L-1Na2SeO3 could relieve salt stress in pakchoi.