多花黄精叶表皮的发育

通过光学显微镜和电子扫描显微镜,对多花黄精(P olyg ona tum cy rtonem a)不同发育时期的叶表皮细胞及其气孔器进行了研究。结果表明:(1)多花黄精叶片的上下表皮细胞的发育方式基本一致,都是表皮细胞进行伸长生长和加宽生长,且伸长生长速度大于加宽生长速度。(2)气孔器的发育方式有两种:由表皮细胞进行不均等分裂所形成的两个细胞之中较小的一个发育而来;直接由表皮细胞发育而来。(3)在叶片发育过程中,气孔器指数是由低到高;在叶片展开第1天达到最高值,随后逐渐降低并趋于稳定。

Leaf Epidermis Development of Polygonatum cyrtonema

Leaf-epidermis cells and stomatal apparatuses of Polygonatum cyrtonema at its different developmental stages were examined by light and scanning electron microscopy.The results showed(1) The cells in upper and lower leaf epidermises of P.cyrtonema grew in a basically identical manner,that is,by their elongating and widening,and the elongating rate was higher than the widening rate.(2) The stomatal apparatuses had two developmental ways,one of which are that they developed from smaller cells in the unequal division of the leaf-epidermis cells and the other of which was that they developed directly from leaf epiderims cells.(3) The stomatal apparatus index increased from low to high with leaf development,reaching its peak one day after leaf expansion and then gradually declining until stabilized.