钙离子对盐胁迫小麦幼苗脯氨酸含量及其相关酶活性的影响

Effects of calcium on proline content and related enzymes activities in wheat seedlings under salinity

研究了Ca2+对盐胁迫小麦幼苗脯氨酸含量及相关酶活性的影响.结果表明,脯氨酸含量在低盐胁迫下增加不明显,高盐胁迫下显著增加;可溶性糖含量及吡咯琳-5-羧酸还原酶(P5CR)活性与其变化趋势一致;吡咯琳-5-羧酸合成酶(P5CS)活性在盐胁迫下变化不明显;脯氨酸脱氢酶(PDH)活性在高盐胁迫下显著增加;盐胁迫下K+含量显著降低,Na+含量明显增加.加入Ca2+后,脯氨酸含量在低盐胁迫下变化不明显,高盐胁迫下显著降低,与可溶性糖含量和P5CR活性变化一致;Ca2+对P5CS活性无明显影响,而使高盐胁迫下PDH活性显著增加;Ca2+明显降低了盐胁迫下Na+含量,提高了K+含量及K+/Na+.这说明脯氨酸仅在高盐胁迫下显著积累,Ca2+明显降低了高盐胁迫下的脯氨酸含量,这一效应主要与P5CR活性降低、PDH活性及K+/Na+增加有关.

Effects of calcium on proline content and the relevant parameters were investigated in saltstressed wheat seedlings. The results showed that proline content exhibited minor enhance under low salinity and significant increase under high salinity. Water-soluble carbohydrates and Δ＇ - pyrroline - 5 -carboxylate reduetase （P5CR） activity showed the same changing trend as proline. Δ＇ -Pyrroline - 5 -earboxylate synthetase （P5CS） activity expressed insignificant changes under salinity. Proline dehydrogenase （PDH） only showed obvious increase under high salinity. Under salt stress K^＋ content was obviously reduced, while Na^＋ showed significant increase. After Ca^2＋ was applied, proline did not show obvious changes at low salinity, but showed significant decrease at high salinity, and their contents changed according to water-soluble carbohydrates content and P5CR activity. Ca^2＋ did not show obvious effect on P5CS activity and significantly increased PDH activity under high salinity. Ca^2＋ obviously decreased Na^＋ content, increased K^＋ content and the ratio of K^＋/Na^＋ in sah-stressed wheat seedlings. These results suggested that proline significantly accumulated only at high salinity, and Ca^2＋ could deduce obvious decrease in proline content in high salinity-stressed wheat plants. This effects might be related to the obvious decrease in P5CR activity and significant increase in PDH activity and the ratio of K^＋/Na^＋.