鹽分處理菠菜對其Betaine Aldehyde Dehydrogenase之影響

The Effect of Salt Stress on the Betaine Aldehyde Dehydrogenase in Spinach

菠菜幼苗培養於水耕溶液，逐步增加溶液中食鹽的濃度。由50 mM NaCl至300 mM NaCl 處理期間，分別測定對照組與處理組之植株地上部及根系之鮮重量，Betaine aldehyde DH， Malate DH，Phosphatase及Peroxidase之活性。結果顯示betaine aldehyde DH只分佈於植株地上部，且於植株接受了150 mM NaCl處理後，酵素活性有明顯增加，至300 mM NaCl處理後，此酵素活性增加3倍左右。然而鮮重量，Malate DH，Alkaline phosphatase活性均於鹽分高過150 mM NaCl時，已有抑制現象。此情形同時發生於植株地上部及根系。由此結果討論菠菜植株於鹽分處理後，betaine aldehyde DH之活性增加，反映了betaine 生物合成步驟之增加，因此作為菠菜以osmoreglation來抗鹽的一種機制。

The growth, betaine aldehyde dehydrogenase, malate dehydrogenase, phosphatase and peroxidase of spinach have been measured over a range of salinities. A slight decrease in fresh weight of the shoot was found with increasing salinity above 100 mM NaCl; at 300 mM NaCl, the fresh weight growth of the root, or the cotyledon was drastically inhibited. Tissue enzyme activities were studies throughout the experimental range. Betaine aldehyde dehydrogenase was restricted to the shoot of spinach, not detected in the root or the cotyledon. Betaine aldehyde dehydrogenase increased significantly at 150 mM NaCl, and 3-fold increase at 300 mM NaCl. However, fresh weight growth, malate dehydrogenase, alkaline phosphatase showed the similar inhibition at a salinity higher than 150 mM NaCl. Peroxidase of salinized spinach was stimulated slightly. It was suggested that the increased betaine aldehyde dehydrogenase of salinized spinach may reflect the betaine biosynthetic pathway accelerated somehow by an incremental salt stress.