Development Of Asexual Reproduction Organ In Three Pinellia Species

To characterize the difference of asexual reproduction in Pinelia,three species [Pinellia ternata(one bulbil on leaf),P.cordata(two bulbils on leaf),and P.integrifolia(no bulbil on leaf)] were used in this thesis.Differences were revealed in morphology,anatomy,and in vitro culture.The main results were as follows:1.The differences of the bulbil development on morphology.The location of the bulbil on blade was sure,but the petiole was not.Bulbil development of P.cordata and P.ternate also contained three phases: no obvious phenomenon,the early bulbil,and the expanding to mature bulbil.The matured bulbils of P.cordata and P.ternate generally were gray ellipsoidal and black spherical,respectively.The diameter of the P.cordata and P.ternate were 2.79±0.40 mm(bulbil on leaf),2.69±0.36 mm(bulbil on petiole)and 7.40 ± 0.14 mm,respectively.2.Bulbil anatomy of the two plants in different developmental stages.The bulbil of P.cordata was formed in the lower part of petiole and the base of leaf blade,the bulbil of P.ternata was formed in the lower part of petiole.The initiated cell was started from the parenchyma cells that located in the petiole front lower epidermis.The primordium differentiated to form the shoot apical meristem(SAM)and to form the infant bulbil.The process of bulbil development could be divided into three stages: formation of primordium,expanding with regeneration and ripening.The inner cells of the maturated bulbils contain lots of nutrients.The result indicated that the development of bulbil in P.cordata was similar to the formation of bulbils in P.ternata.3.In vitro culture of the three plants were established or optimized.Leaves and petioles were used as explant for in vitro culture of P.cordata.The petiole was proved to be the best explants for callus inducing.The reproductive cycle of P.cordata was shorted to 44 days by optimizing the callus induction,differentiation and rooting culture.The propagation system of P.integrifolia was established.The tuber was better explant than the blade or petiole.Yellow and loose callus,which was suitable for propagation culture,could be induced with MS+6-BA 2.0 mg/L + NAA 0.5 mg/L.Adding NAA and 2,4-D in medium resulted in the formation of loose and compact density callus,respectively.The Murashige and Skoog's medium(MS)supplied with 6-BA 2.0 mg/L + NAA 0.2 mg/L and medium MS + IBA 0.5 mg/L+6-BA 0.1 mg/L were used for differentiation and rooting culture.