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为研究根瘤共生对紫花苜蓿(Medicago sativa)耐碱性及有机酸含量的影响,本研究以龙牧806为材料,用200 mmol/L Na HCO_3胁迫处理正常植株与接种根瘤菌植株0、4、6、8天,分别测量根中苹果酸、柠檬酸、琥珀酸、草酸、酒石酸、乙酸的含量。结果表明,根瘤共生有效的提高了苜蓿对盐碱胁迫的耐性;正常植株在胁迫第4天时,苹果酸、柠檬酸、草酸、酒石酸的含量大幅度显著下降,而后小幅度减少,胁迫第8天时有所提高,琥珀酸则在胁迫第6天大幅度下降,后稍有增加;相对于正常植株来说,接种根瘤菌的植株,有机酸含量波动较小,草酸和酒石酸平稳减少,柠檬酸和琥珀酸随着胁迫时间延长,含量逐渐增加,胁迫第6天达到最高值,然后减少,苹果酸在胁迫第4天时含量增加,而后逐渐减少。综上所述,接种根瘤菌可减缓盐碱胁迫对植株根的伤害,共生根瘤提高苜蓿的耐碱性一部分是通过调节有机酸含量的变化实现。
In order to study the effect of root nodules symbiosis on the alkalinity and organic acid content of alfalfa (Medicago sativa), Longmu 806 was used to treat normal plants and inoculated Rhizobia strains 0 and 4 with 200 mmol / L Na HCO 3 stress. 6, 8 days, were measured in the root of malic acid, citric acid, succinic acid, oxalic acid, tartaric acid, acetic acid content. The results showed that root nodules symbiosis effectively increased the tolerance of alfalfa to salinity-alkalinity stress. The contents of malate, citric acid, oxalic acid and tartaric acid decreased significantly in normal plants on the 4th day of stress, and then decreased slightly. On the 8th day of stress Compared with the normal plants, the plants inoculated with Rhizobia had less fluctuation of organic acids and a steady decrease of oxalic acid and tartaric acid. Compared with citric acid and Succinic acid increased gradually with the prolongation of stress time, reaching the highest value on the 6th day of stress and then decreased. The content of malic acid increased on the 4th day of stress and then decreased gradually. In summary, inoculation Rhizobium can slow down the salt-alkali stress on plant roots damage, symbiotic nodules increase alfalfa alkali resistance is partly through the regulation of organic acid content changes.