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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。
Cellulase activity in cortical cells gradually disintegrated during induction of air-induced tissue formation by adventitious root submergence in maize was determined by a cytochemical method using Benzene reagent and hydroxymethylcellulose hydrolyzing reducing sugars. Precipitated particles showing enzymatic activity first appeared in a few cortical cells 4 mm away from the root tip and were distributed along the cell wall. In the cortex tissues 5 to 6 mm from the root tip, the number of cortical cells with precipitated particles increased, The density of sediment was also significantly increased, and the precipitated particles were still distributed evenly along the cell wall. In the cortex cells 7-8 mm away from the root tip, although the precipitated particles were still mainly distributed along the cell wall, the original uniform distribution changed to the discontinuous distribution of aggregated state. Within 9 mm of the apical cortex cells, the precipitated particles are distributed on the cell wall in an aggregated state. Within 10 mm of the apical cortex tissue, the cytoplasm of some cells was completely digested, and the cell wall was also significantly degraded and remained. Venous tissue began to form within 11 mm of the apical cortex as the cortical cells at the local site were completely digested. The results show that the expression of cellulase activity is closely linked with the cell wall degradation of cortical cells, supporting the hypothesis that the cellulase proposed in the previous paper is involved in the process of aerenchyma formation.