建兰类原球茎体生长、发育过程中扫描电镜观察

建兰(Cymbidium ensifolium)类原球茎体(PLB)培养在含3％蔗糖和不含蔗糖的1/2 MS_0培养基中生长,比较连续光照、8h光照和黑暗条件下原球茎生长发育的动态进程。扫描电镜观察表明:原球茎表面布满密集的发育程度不同的分生区,随继代培养进程,形成分株更多的丛生形原球茎,连续光照促进分生区的增殖,黑暗不利于分生区的发育,在无糖源培养基中生长的PLB,分生区的细胞伸长,发育呈管状结构,这种结构丧失分生能力。在原球茎顶端分化叶原基,并可分化类似气孔的保卫细胞。

Observations on the Growth and Development of PLBs in Cymbidium with Scanning Electron Microscope

The protocorm-like bodies(PLBs) of Cymbidium ensifolium were cultured in two 1/2 MS_0 media with or without 3% sugar. The growth and development courses of PLBs were compared under continuous illumination, 8h illumination or in the dark. The results from SEM observations showed many meristematic regions at different development stages distributed on the surfaces of PLBs. The cells in meristematic regions developed into rosette PLBs and thus multiplied. Continuous illumination enhanced the multiplication of meristematic regions, while continuous darkness was unfavorable to the development of meristematic regions. When the PLBs were cultured in the medium without sugar, the cells in meristematic regions elongated and developed into tube-like tissues and lost the capacity to multiply. Leaf primordia were found on the tips of PLBs, which differentiated into cells resembling the guard cells of stomata. It has been shown that germination, development and multiplication of PLBs, and the formation of plantlet from tissue culture were a successive process, and meristematic regions with different development stages, PLBs and plantlets were found simultaneously in same culture medium.