棉胚珠培养的研究

The Study of Culture of Cotton Ovules

运用 A.C.Beasley & I.P.Ting 棉胚珠离体培养基,对花后2天陆地棉品种中棉12的胚珠培养表明:①培养胚珠上纤维的伸长变化也呈 S 型曲线,整个发育进程缩短,最后的长度仅为自然长度的一半左右。②偏光镜检表明,离体条件下,次生壁累积提前。因而认为,过早的次生壁合成的起始限制了纤维的进一步伸长。③偏光及 SEM 连续观察发现,从珠孔端愈伤组织处产生的胚珠衍生细胞可能具发育成成熟维的能力。同时,对培养胚珠与水面相接触一侧的类纤维细胞也进行了追踪调查,缺氧滞水使原本为纤维发育方向的细胞最终形成的是绒状长细胞。此类细胞也是高度仲长且具纤维次生壁。但同纤维细胞相比,其长度和次生壁厚度均不及纤维细胞,而直径却是纤维细胞的2倍以上。④石蜡切片研究,表明纤维的分化突起是胚珠或其表皮细胞本身具有的生理生化机制,而非整株植物的效应。离体培养虽脱离了母体的影响,但并不影响纤维的继续分化突起。另一种可能性是,胚珠表皮细胞在开花前的某一时期已分化形成预纤维细胞和非预纤维细胞两类。

Applied BT-medium to in vitro growth of cotton ovules of Zhong -12(Gossypium hirstum L.) two days after anthesis,the results show as follows: ①Change of elongation of fibers cultured in vitro are similar to those of fibers grown on the plant.The entire developmental sequence seems to be com pressed in time in culture,and the fiber cells on cultured ovules reach leng- ths approximately one half of that achieved by in intact plant. ②Fibers have an earlier onset of secondary wall deposition in culture than in planta according Olympus polarizing microscope.This may be account for the shorter final fiber length in vitro. ③Ovule-derived cells from micropylar region callus may have potential to grow mature fibers.Fine-hair long cells are originated from epidermal cells on the surface of developing cotton ovules which are in contact with the liquid medium.The two kinds of cells have high elognation and deposition of cellulose secondary wall. ④Histology observation indicate fiber differentiation is decided by ovule or its epidermal cells.It has nothing to do with the intact plant. It is possible for ovule epidermal cells that have differentiated prefibre and no-prcfibrc cells at a certain time before anthesis.