盐度和CO_2倍增环境下碱蓬幼苗呼吸酶活性的变化

Variation of respiratory enzyme activities of Suaeda salsa seedlings under salinity and doubled CO_2.

研究了生长在正常大气ＣＯ２和ＣＯ２倍增环境中的盐生植物碱蓬（Ｓｕａｅｄａｓａｌｓａ）幼苗呼吸酶活性对ＫＣｌ和ＮａＣｌ的反应．结果表明，在ＣＯ２倍增（７００μｌ·Ｌ－１）和正常大气ＣＯ２（３５０μｌ·Ｌ－１）下，３００ｍｍｏｌ·Ｌ－１ＫＣｌ和ＮａＣｌ均能抑制琥珀酸脱氢酶（ＳＤＨ）和苹果酸脱氢酶（ＭＤＨ）活性，而异柠檬酸脱氢酶（ＩＤＨ）活性为ＮａＣｌ抑制、ＫＣｌ促进；ＮａＣｌ和ＫＣｌ明显抑制细胞色素氧化酶（ＣＯ）和光呼吸中乙醇酸氧化酶（ＧＯ）、羟基丙酮酸还原酶（ＨＰＲ）活性；并指出在ＫＣｌ胁迫下，ＣＯ２使三羧酸循环（ＴＣＡＣ）的运行变慢，ＮａＣｌ胁迫下使其加快，ＴＣＡＣ运行限速步骤与ＭＤＨ无关，ＣＯ为盐对呼吸代谢影响的重要位点．另外，Ｋ＋、Ｎａ＋对蛋白表达的影响有差异，ＣＯ２可使盐胁迫下的碱蓬幼苗蛋白表达降低．

Studies on the response of respiratory enzyme activities of halophyte Suaeda salsa seedlings growing under normal (350μl·L -1 ) and doubled (700μl·L -1 ) concentrations of CO 2 to KCl and NaCl show that under normal and doubled concentrations of CO 2, the activities of succinic dehydrogenase(SDH), malic dehydrogenase (MDH), Cytocrome Coxidase (CO), glycolate oxidase (GO) and hydroxypyruvate reductase (HPR) were inhibited by 300mmol·L -1 KCl and NaCl;the activity of isocitric dehydrogenase (IDH) was decreased by NaCl, but increased by KCl. The operation rate of tricarboxylic acid cycle (TCAC) was deceleratedby CO 2 under KCl stress, but accelerated under NaCl salinity. The steps of limiting speed by TCAC's operation was not related with MDH. CO is the important site of salt affecting respiratory metabolism. Moreover, the influence of K + on protein expression was different from that of Na +, and CO 2 could reduce the protein expression of Suaeda salsa seedlings under NaCl and KCl stresses.