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研究了在150 mmol·L~(-1) NaCl胁迫下含铵态氮、硝态氮和硝酸铵(氮素浓度均为3 mmol·L~(-1))的营养液培养的番茄幼苗生长、细胞超微结构、根系活力和光合作用参数的变化。结果表明:NaCl胁迫下,硝态氮处理叶片细胞出现伤害现象,而硝酸铵处理未见明显变化。铵态氮处理细胞超微结构明显发生破坏性变化,盐胁迫下,其伤害加剧。NaCl处理下,不同氮素形态处理下的植株生物量和根系活力均显著下降,其中硝酸铵处理的植株生物量和根系活力维持最高。NaCl胁迫下3种氮素形态处理的植株净光合速率(Pn)和蒸腾速率(Tr)均显著下降,其中硝酸铵处理的Pn和Tr要明显高于其他氮素处理。NaCl胁迫下,硝态氮处理和硝酸铵处理的水分利用效率(WUE)和气孔限制值(Ls)均明显上升,而铵态氮处理显著降低。综上,盐胁迫下,硝酸铵处理下番茄幼苗可维持较好的细胞超微结构、根系活力和较高的光合作用,维持较高的生物量,从而维持较高的耐盐性。
The growth of tomato seedlings cultured in nutrient solution containing ammonium, nitrate and ammonium nitrate (3 mmol·L -1) was studied under 150 mmol·L -1 NaCl stress , Cell ultrastructure, root activity and photosynthesis parameters. The results showed that under NaCl stress, NO3 - N treatment resulted in injury to leaf cells, while no significant changes were observed in ammonium nitrate treatment. The ultrastructure of the cells treated with ammonium nitrogen obviously destructive changes, under salt stress, the injury intensified. Under NaCl stress, the plant biomass and root vigor decreased significantly under different nitrogen forms, of which ammonium nitrate treatment maintained the highest biomass and root activity. Under NaCl stress, the net photosynthetic rate (Pn) and transpiration rate (Tr) of three nitrogen forms significantly decreased, while the contents of Pn and Tr in ammonium nitrate treatment were significantly higher than those of other nitrogen treatments. Under the NaCl stress, the WUE and the stomatal limitation (Ls) of nitrate nitrogen treatment and ammonium nitrate treatment significantly increased, while ammonium nitrogen treatment decreased significantly. In conclusion, under salt stress, the seedlings of tomato seedlings could maintain better cell ultrastructure, root activity and higher photosynthesis, maintain higher biomass, and thus maintain higher salt tolerance.