红海榄幼苗根系呼吸代谢对水淹胁迫的响应

本研究利用人工潮汐系统(每天淹水0、6、12和18h), 研究了红海榄幼苗根系呼吸代谢对水淹胁迫的响应。结果表明, 每天淹水6h对红海榄幼苗的生长影响不大, 但随着水淹时间的延长, 红海榄幼苗的生长显著受到抑制。水淹时间的延长同样明显抑制了红海榄幼苗根系的产能效率, 且根系三羧酸循环的有氧呼吸速率、三磷酸腺苷含量以及琥珀酸脱氢酶和苹果酸脱氢酶活性最小值均出现在每天水淹18h处理组中。相反, 水淹胁迫下红海榄幼苗根系乙醇脱氢酶、乳酸脱氢酶活性以及乙醇和乳酸含量都呈上升的趋势。综上, 尽管无氧呼吸可一定程度上缓解三羧酸循环受阻所导致的产能匮乏, 但是过度的水淹胁迫仍会扰乱红海榄幼苗正常的生长和代谢, 导致三磷酸腺苷产能效率的降低以及无氧发酵代谢产物的积累。

Response of respiratory metabolism in the roots of Rhizophora stylosa to waterlogging

In this study, artificial-tidal systems (0, 6, 12, 18 h·d^-1) were employed to explore the effect of waterlogging on respiratory metabolism in the roots of Rhizophora stylosa. The results showed that 6 h·d^-1 waterlogging treatment appeared to has little negative effect on plant growth. However, the biomass yield efficiency decreased significantly with the elongation of waterlogging duration. Tricarboxylic acid respiratory rate, adenosine-triphosphate content, and the activities of succinate dehydrogenase and malate dehydrogenase were also obviously inhibited by long-duration waterlogging, especially in the treatment of 18 h·d^-1. On the contrary, alcohol dehydrogenase, lactate dehydrogenase, and the contents of alcohol and lactate increased with the elongation of waterlogging duration. In summary, although anaerobic respiration can partly alleviate energy deficiency caused by the inhibition of tricarboxylic acid cycle, excessive waterlogging would disrupt normal growth and metabolism of R. stylosa, leading to declined adenosine-triphosphate productivity and increased anaerobic fermentative metabolites.