短期低温对大豆苗期生长和结瘤固氮的影响

Effect of Short-Term Low Temperature on Seedling Growth and Nodule Nitrogen Fixation in Soybean

采用早熟大豆品种“黑河43”、晚熟大豆品种“东农53”进行盆栽试验,出苗后进行连续7d的低温处理(LT),昼夜温度设定为13℃/3℃,以25℃/10℃为对照,从大豆出苗28d开始,每7d进行破坏性取样共4次,测定地上部和根干物质量、根瘤生物量、全氮含量及根瘤固氮量,研究苗期短期低温对大豆生长、结瘤和固氮能力的影响。结果表明:(1)大豆出苗后7d短期低温胁迫会延缓大豆生长发育。出苗后28~42d大豆生物量显著低于CK处理,出苗后49d低温胁迫对两个大豆品种生物量均无显著影响。(2)与CK相比,低温对“东农53”和“黑河43”根瘤形成的显著抑制作用分别出现在苗后42d和35d,根瘤数量分别降低了58.8%和72.0%。出苗后49d,低温使“东农53”和“黑河43”根瘤干重分别减少48.9%和48.5%。(3)低温刺激了两个品种大豆的生物固氮能力。在出苗后49d,低温处理“东农53”和“黑河43”的生物固氮量、单位根瘤生物量的固氮量和单个根瘤的固氮量分别增加了89.9%、118.9%,249.3%、172.6%,150.6%、114.2%。生物固氮百分率分别增加了26.4个和24.5个百分点。综合来看,大豆出苗后遭遇低温冷害会延缓生长发育,并抑制根瘤的形成与生长。低温胁迫解除后大豆生长逐步恢复。短期低温对大豆根瘤固氮量和根瘤固氮能力有刺激作用,对早熟品种“黑河43”刺激作用更明显。为了更好地适应东北大豆产区早春低温环境,推荐选用早熟品种大豆。

In this study,potted experiments were conducted using the early-maturing soybean variety"Heihe 43"and the late-maturing soybean variety"Dongnong 53"under low temperature treatment(LT).The shoot and root dry weights,nodule biomass,total nitrogen content,and nodule nitrogen fixation were measured in the 28-49 days after soybean emergence.The results showed that:(1)low-temperature stress encountered by soybeans in the first week after emergence would delay soybean growth and development.From the 28d to 42d after emergence,soybean biomass was significantly lower than that of the CK treatment under low-temperature stress,but no significant difference was observed in the biomass of the two soybean varieties until the 49d after emergence.(2)In comparison to CK,significant inhibition of nodule formation in"Dongnong 53"and"Heihe 43"by low temperature occurred in the 42d and 35d after emergence,and the number of nodules decreased by 58.8%and 72.0%,respectively.During the 49d after emergence,low temperature decreased the dry weight of nodules of"Dongnong 53"and"Heihe 43"by 48.9%and 48.5%,respectively.(3)Low temperature stimulated the nitrogen fixation ability of two soybean varieties.At 49d after seedling emergence,the biological nitrogen fixation,nitrogen fixation per unit nodule biomass and nitrogen fixation per individual nodule of"Dongnong 53"and"Heihe 43"at low temperature increased by 89.9%,118.9%;249.3%,172.6%and 150.6%,114.2%,respectively.The percentages of biological nitrogen fixation increased by 26.4 and 24.5 percentage points,respectively.Collectively,low temperature stress after soybean emergence can slow down growth and development,and inhibit the formation and growth of nodules.However,soybean growth will gradually recover after the release of low temperature stress.Short-term low temperature stress has a stimulating effect on the nitrogen fixation of soybean nodules and their nitrogen fixation ability,and the stimulating effect is more pronounced for the early-maturing variety"Heihe 43".Therefore,it is recommended choosing early-maturing soybean varieties to better adapt the early spring low temperature environment in the soybean production area of Northeast China.