水稻癒合組織中管細胞的分化

Abstract

生長激素對水稻癒合組織之生長影響甚大，2，4—D能維持組織正常的生長，NAA單獨處理或分別與Kinetin、BA配合處理癒合組織，造成大量迅速褐化的組織。這幾種生長激素均可誘導癒合組織進行管細胞的分化，但分化率均不高，只有含2ppm 2，4—D與1ppm kinetin的培養基上，可產生一種白色硬塊的組織，可有8％的管細胞分化率。組織切片顯示這類組織中有大量管細胞形成分叉狀，團狀或帶狀的聚集，薄壁細胞及厚壁細胞交錯分佈其間。分化中的管細胞及其附近細胞均有退化現象，胞器漸消失，並有多量油滴產生，成熟的管細胞不具細胞內容物，只能見到各種形式次生細胞壁的不均勻加厚。組織的過氧化?可分為soluble fraction與wall-bounded fraction，ionically bounded wall peroxidase的活性在培養第2天與第21天各有一高?。組織中同功酵素帶最多可達8個。

Hormonal effects on growth of rice calli are quite remarkable. Calli can maintain normal growth in the presence of 2, 4-D. NAA treatment or NAA-kinetin, NAA-BA combined treatments produce lots amount of rapidly browning tissues. All these growth hormones are capable of inducing tracheary element differentiation in calli, yet with a low yield. On culture medium containing 2ppm 2, 4-D and 1ppm kinetin, can calli produce a white and hard block with 8% cell being tracheary elements forming fork, nodule or band-like aggregates, with parenchyma or sclerenchyma in it. Differentiating tracheary element and nearby parenchyma both show degeneration phenomena, organelles disappear gradually, with lots of oil drops in it. Mature tracheary elements contain no more organelle, only all kinds of uneven thickening of secondary wall can be seen. Peroxidases of the tissue are presented in two compartments. One is in soluble fraction, and the other locates on cell wall. The activity of wall-bounded peroxidase shows peaks on 2nd day and 21th day of culture respectively.