【摘要】 烟草叶肉细胞质外体(apoplast)中过氧化物酶(即与壁游离的过氧化物酶)的活性,从幼嫩的叶片到成熟的叶片,有一个从低到高,呈S形变化的曲线。聚丙烯酸胺凝胶电泳,同工酶谱带变化如下:第一叶只有一组(AⅡ组),第二叶开始增加至两组(AⅡ组、AⅠ组),到第七叶又只有一组(AⅠ组),AⅡ组消失了。这反映细胞生长的不同阶段有不同的同工酶在起作用。 与烟草叶肉细胞壁结合的过氧化物酶,都定位于AⅠ组,其中有两种同工酶是以离子键结合于壁的,有一种以共价键结合于壁。更多还原

【Abstract】 In healthy tobacco plants (Nicotiana tabacum), activity of the peroxidasewhich is present in the apoplast of mesophyll cells but absent in the cell walls wasfound to change with the growth and development of the leaf As illustrated inFig. 1, peroxidase activity is lower in the young leaf and becomes higher in themore mature leaf Activity change with age seems to follow an S-shaped cur-ve. When isolated by acrylamide gel electrophoresis, the peroxidase isozymesfrom leaves differently situated on the plant show quite different characteristics.The isozymes from the top leaf fall into only one group (A Ⅱ), those from the se-cond leaf fall into two groups (AⅡ and AⅠ), and those from the seventh leaf fallagain into only one group (AⅠ) with the AⅡ group disappeared. This shows thatdifferent peroxidase isozymes function in different periods of cell development inleaf growth. Peroxidase isozymes bound to the cell wall are in the AⅠgrqup which mig-rate to anode with a higher rate. Two bands of the AⅠ group isozymes are ionically wall-bound, and the remaining one is co-valently wall-bound.更多还原