NaCl胁迫诱导小麦叶片内肽酶活力变化的研究

利用抗盐小麦品种德抗961研究了不同浓度NaCl胁迫对小麦叶片内肽酶活性、叶绿素含量及可溶性蛋白质含量的影响。结果表明,低浓度(20 mmol/L)的NaCl处理对小麦叶片中内肽酶活力、可溶性蛋白质和叶绿素含量的影响不大,而高浓度(50、100、200 mmol/L)NaCl处理可使小麦幼苗叶片中内肽酶活性升高,可溶性蛋白质含量和叶绿素含量下降。用激活剂和抑制剂处理结果表明,NaCl胁迫引起的叶片老化与叶片正常衰老一样,其过程中至少存在3种内肽酶(巯基蛋白酶、丝氨酸蛋白酶和金属蛋白酶),而在蛋白质降解中起主要作用的是巯基蛋白酶。以酪蛋白为底物时,内肽酶的最适温度为42℃,最适pH值为4.8。

Effects of NaC1 Stress on Endopeptidase Activity in Wheat Leaves

Salt tolerance variety Dekang 961 was used to study the effect of different NaCl concentration on endopeptidase activity,chlorophyll content and soluble protein content in wheat leaves.The results showed that changes of endopeptidase activity,chlorophyll content and soluble protein content were not obvious in seedling leaves of Dekang961 under low NaCl concentration,but under high NaCl concentration(50,100,200 mmol/L),the higher endopeptidase activities and lower protein and chlorophyll content were detected.After treatment with different inhibitors and activators,the results showed that there were more than three subclasses of endopeptidases in leaves during leaf aging process,namely thiol-proteases,serine proteinases and metallo-proeinases,among which,thiol-proteinases had the highest activity.The optimum pH-value for casein was 4.8 and the optimum temperature was 42 ℃.