【摘要】 采用本氏试剂与羟甲基纤维素水解还原糖反应的细胞化学方法,对玉米不定根淹水诱导形成通气组织过程中,逐步解体的皮层细胞内纤维素酶活性进行了定位观察。显示酶活性的沉淀颗粒首先出现在离根尖4 mm的少数皮层细胞中,沿细胞壁分布;在离根尖5~6 mm的皮层组织内,有沉淀颗粒的皮层细胞数量增多,而且沉淀颗粒的密度也显著增大,沉淀颗粒仍沿细胞壁均匀分布;在离根尖7~8 mm皮层细胞内,沉淀颗粒尽管仍主要沿细胞壁分布,但由原来的均匀分布变为凝集态的不连续分布。在离根尖9 mm的皮层细胞内,沉淀颗粒则以凝集态分布在细胞壁上。在离根尖10 mm的皮层组织内,部分细胞的细胞质被完全消化,细胞壁也被明显降解,呈残余态。随着局部位置的皮层细胞完全消化,在离根尖11 mm的皮层组织内开始形成通气组织。研究结果显示纤维素酶活性的表达与皮层细胞的细胞壁降解紧密相联,支持前人提出的纤维素酶参与了通气组织形成过程的假说。更多还原

【Abstract】 Cellulase activity in adventitious roots of maize during aerenchyma formation induced by flooding was locatedthroughthe reaction of Benedict’s reagent withreducingsugars liberated by hydrolysis of carboxymethylcellulose(CMC).The electron-dense deposits,indicatingthe presence of cellulase activity,werefirstlyobservedinafewcortical cells 4 mmbehindroot tips.In the root zones 4 to 10 mmbehind tips,the cortical cells containing deposits gradually increased innumber,and the deposits located in these cells showed remarkably increased in density.Meanwhile,the deposits alsoaltered significantlyinpatternof distribution.Atthe earlierstage,the deposits were mainlylocatedalongthe cell wall,andacross the cell wall atthelater stage.Withthe complete degenerationof some cortical cells,aerenchyma wasformedinthecortex11 mmbehindtips.The present results support the hypothesisthat an enhanced cellulase activityisinvolvedinthelysis of cortical cells leadingto aerenchyma formation under a waterlogged condition.更多还原