滴水珠珠芽发育过程研究.

Tuber of Pinellia cordata has been the extensively used as medicines in the practice of traditional Chinese medicine. Bulbil formation is the main propagation strategy of P. cordata in wild. There are two developmental stages of bulbils for each one individual: on the basis of leaf blade (upper bulbil) and on the lower part of petiole (lower bulbil). To reveal the developmental characteristics of bulbil formation in P. cordata, morphological and anatomical observation were systematically used. Morphological observation showed that the whole development process of upper or lower bulbil could be divided three stages: no visible bulbil structure, primary bulbil formation under epidermis, growth and maturation of bulbil. Correspondingly, anatomical observation showed that the whole development process of upper or lower bulbil could be divided four stages: initial cell formation, bulbil promodia formation, differentiation of bulbil, and bulbil growth continuously to maturation. The initial cell of bulbil was derived or dedifferentiated from the parenchyma cell which was located in the adaxial side of young petiole. Initial cell formation was not visible. Continuously division of the initial parenchyma cell resulted in the formation of bulbil primodium, which was a group of undifferentiated cell. The primordium continuously growth and then differentiated to form the shoot apical meristem (SAM), which was the infant bulbil on the adaxial side. Bulbil promodium formation and early primodium differentiation could be visible with white dot structure on petiole. Subsequently, differentiated bulbil growth and lateral scale leaf differentiation continuously characterized the bulbil growth stage. Bulbil growth terminated with the leaf senescence. The average diameter of maturated upper bulbil on blade and lower bulbil on petiole were (2.79 ± 0.40) mm and (2.69 ± 0.36) mm, respectively. The maturated bulbils generally were gray and ellipsoidal, and shaped with various number of external scale leaf. The inner cells of maturated bulbil contained lots of nutrients (storage). The germination rate of bulbils was up to 75% in soil culture. Morphological and anatomical observation results indicate that the development of bulbils in P. cordata is the same in P. ternata, and the development of bulbil in P. cordata is an effective reproduction strategy just like in P. ternata. [ABSTRACT FROM AUTHOR]