关键词: 淹水, 玉米, 皮层细胞解体, 通气组织形成, 纤维素酶活性超微细胞化学定位

Abstract:

Cellulase activity in adventitious roots of maize during aerenchyma formation induced by flooding was located through the reaction of Benedict’s reagent with reducing sugars liberated by hydrolysis of carboxymethylcellulose (CMC). The electron-dense deposits, indicating the presence of cellulase activity, were firstly observed in a few cortical cells 4 mm behind root tips. In the root zones 4 to 10 mm behind tips, the cortical cells containing deposits gradually increased in number, and the deposits located in these cells showed remarkably increased in density. Meanwhile, the deposits also altered significantly in pattern of distribution. At the earlier stage, the deposits were mainly located along the cell wall, and across the cell wall at the later stage. With the complete degeneration of some cortical cells, aerenchyma was formed in the cortex 11 mm behind tips. The present results support the hypothesis that an enhanced cellulase activity is involved in the lysis of cortical cells leading to aerenchyma formation under a waterlogged condition.

Key words: Flooding, Maize, Lysis of cortical cells, Aerenchyma formation, Ultracytochemical localization of cellulase activity