不同耐铝型小麦品种苹果酸分泌差异与有机酸代谢关系研究

铝胁迫下不同耐铝型植物有机酸分泌存在显著差异,有机酸主要在三羧酸循环途径中产生,但目前有机酸分泌差异与有机酸代谢关系还不是很清楚。以耐铝型小麦Triticum aestivum L.品种ET8和铝敏感型小麦品种ES8为材料,研究了铝胁迫对不同耐铝小麦品种根内源苹果酸含量及磷酸烯醇式丙酮酸脱氢酶（PEPC）,柠檬酸合成酶（CS）和苹果酸脱氢酶（MDH）等酶活性的影响。结果表明：铝处理（0、25、50、100μmol.L-1）对内源苹果酸含量无显著影响,相同处理条件下ET8和ES8间亦无显著差异,分别为每根尖（0.48±0.01）、（0.46±0.03）、（0.57±0.02）、（0.52±0.02）nmol和（0.45±0.02）、（0.51±0.09）、（0.51±0.11）、（0.54±0.04）nmol;同无铝处理相比,50或100μmol.L-1铝处理显著促进ET8和ES8根尖细胞PEPC活性升高,但各铝浓度处理对CS和MDH活性无显著影响;相同处理条件下ET8和ES8根尖细胞PEPC,CS和MDH 3种酶活性均无显著差异。综上所述,铝胁迫下不同耐铝小麦品种根苹果酸分泌差异与内源苹果酸含量及有机酸代谢无关。

The relationship between malic acid secretion differences and organic acid metabolism of wheat with different Al-tolerant levels

There are significant differences of organic acid secretion among species that with different Al-tolerant levels under Al stress.Organic acid is produced during the tricarboxylic acid cycle pathway.However,the relationship between organic acid secretion differences and organic acid metabolism are still needed to be identified.This experiment was performed by two wheat（Tritium aestivum L.） cultivars,ET8（Al-resistant） and ES8（Al-sensitive）.Effects of Al on endogenous malic acid content,activities of phosphoenolpyruvate carboxylase（PEPC）,citrate synthase（CS） and malate dehydrogenase（MDH） were studied.Results were as fellows： the contents of endogenous malic acid were not affected by Al（0,25,50,and 100（mol-L-1）,and there were no differences between ET8 and ES8 when they received same treatment.The endogenous malic acid contents were（0.48±0.01）,（0.46±0.03）,（0.57±0.02）,（0.52±0.02） nmol-root apex-1 and（0.45±0.02）,（0.51±0.09）,（0.51±0.1）,（0.54±0.04） nmol-root apex-1,respectively of ET8 and ES8.Compared with Al free treatment,activities of PEPC were increased significantly under Al（50 or 100（mol-L-1） treatment,but not CS or MDH.The activities of PEPC（or CS,MDH） of ET8 and ES8 were close to each other under the same treatment.In conclusion,the malic acid secretion differences of different Al-tolerant wheat were independent on the endogenous malic acid content and the organic acid metabolism.