【摘要】 水分胁迫能引起露花叶片PEP羧化酶的活力、酶蛋白和mRNA水平的提高。复水后，叶片PEP羧化酶表达量降低；茎中的PEP羧化酶在水分胁迫和恢复水分供应过程中变化情况与叶片相似，兼性CAM植物的碳代谢类型转变发生在植物的绿色组织中。露花叶片中除了250kD的PEP羧化酶同功酶外，还有300kD同功酶；主茎的叶片叶位越低，PEP羧化酶活力越高。更多还原

【Abstract】 Mesembryanthemum cordifoliu, is afacultative CAM plant. We found inthis plant that: 1. Water stress elevatedleaf PEPCase activity (Fig. 1 ), thecontent of PEPCase protein (Fig. 4 )and mRNA encoding PEPCase (Fig.5 ). 2. Rewatering lowered the leafPEPCase level (Fig. 1 ). 3. PEPCasesof stem and leaf were affected in thesame way either by water stress or byrewatering (Fig. 2 ). Therefore, it ispossible that the shifting from C3 toCAM occurred in all green parts of theplant when water stressed. 4. Therewas a 300 kD minor PEPCase isocnzyme besides the 250 kD major one(Fig. 2 ). They changed in the sameway during water stress and rewatering(Fig. 2). 5. The PEPCase activity inlower leaves was higher than that in theupper young leaves (Fig. 6).更多还原