摘要： 以玉米为材料，研究了效应剂和pH对绿色和黄化玉米PEP羧化酶活性的协同作用，发现绿苗和黄化苗中PEP羧化酶对效应剂的敏感性不同，前者比后者对G6P、Gly敏感，而后者比前者对Mal敏感。黄化苗经3h光处理后，其PEP羧化酶对G6P的敏感性与绿苗趋于相同。同时发现pH不同，PEP羧化酶对效应剂的敏感性也不同，低pH比高pH时酶对效应剂更敏感。根据绿苗和黄化苗PEP羧化酶活性和对效应剂敏感性的差异推测黄化苗中PEP羧化酶的主要功能不是同化CO₂。

关键词: 玉米, PEP羧化酶, 效应剂, 氢离子浓度, 绿苗, 黄化苗

Abstract: In this paper, the cooperative effects of effectors and pH on the activity of PEPCase and the differences in sensitivities of PEPCase to effectors in green and etiolated maize leaves were studied.It was discovered that the PEPCase in green leaves was more sensitive to G6P and Gly, but less sensitive to Mal than that in etiolated leaves (Fig 1,2,3,4).When etiolated leaves was exposed to light(3000 lx)for 3 hours, the sensitivity of PEPCase to G6P tended to be similar to that in green leaves(Fig 1)The PEPCase in green or etiolated leaves also showed different sensitivities to G6P,Gly and Mal when assayed at different PH, being more sensitive to G6P,Gly and Mal at lower pH (7.4) than at higher pH(9.2)(Fig,2,3,4).The sensitivity of PEPCase to G6P in green leaves at pH9.2 was similar to that in etiolated leaves at pH7.4(Fig.2).This suggested the involvement of cooperative effects of effector and pHon the activity of PEPCase.The reguiatory properties of PEPCase in etiolated leaves by effectors showed that the major function of PEPCase in etiolated leaves might be not to fix CO2 for photosynthesis.

Key words: Maize, PEPCase, Effector, pH, Green seedlings, Etiolated seedlings

中图分类号: 

• S562.01