[Programmed cell death induced by drought stress in sprout tumble of Pinellia ternata].

To further study the mechanism of sprout tumble caused by drought,drought stress was simulating with 30% PEG 6000,physiological,and then the morphological changes of Pinellia ternata cells at different treatment time were detected. The results indicated that,along with the period of drought stress continued,the contents of chlorophyll and water potential were decreased,relative electrical conductivity,contents of soluble sugar and MDA increased. Sprout tumble of P. ternata first occurred on the fourth day during drought stress,large scale of sprout tumble appeared on the eighth day with about 73% of tumble rate. The nuclei exposed to drought stress for 2 days were flattened,lobed,invalidated or irregular in shape and significant showed the apoptotic morphological characteristics. Adenylate transferase( ANT) gene expressions were inhibited by drought,with the rapid increase of Caspase-3 enzyme activity,the cell death rate increased. All this proves that the essence of sprout tumble caused by drought is programmed cell death,which may be a self dormancy protection mechanism of P. ternata against adverse environment.

[EMS mutation of suspension cells and selection of high temperature tolerant mutants from Pinellia ternata].

OBJECTIVE: To determine the optimal concentration and processing time of EMS mutation for suspension cells from Pinellia ternata. METHOD: Under four EMS concentration gradients (0.1% , 0.2%, 0.4%, 0.6%) and three processing time gradients (0.5, 1.0, 2.0 h), the suspension cells of P. ternata were mutagenized. RESULT AND CONCLUSION: The results showed that the survival rate was significantly different under the different concentrations of EMS and the different processing time. In the same processing time, the EMS concentrations were increased, but the suspension cells survival rate decreased gradually. The optimum EMS concentration for the mutagenesis was 0.4% and the best processing time was 1 hour.

[Effect of low temperature on cell synchronization division in suspension culture cells of Pinellia ternata].

OBJECTIVE: To study the effect of low temperature on cell synchronization division in suspension culture cells of Pinellia ternata, in order to find a proper condition for cell synchronization. METHOD: The loosened calli of P. ternata were used as materials. The effect of low temperature on cell synchronization division was studied and researched in suspension culture cells by the method of orthogonal experiment, the obtained experimental data was compared and analyzed through the analysis of range and analysis of variance. RESULT: After the low temperature treatment, the cell division index was increased in various degrees, among the total results, when the temperature was set at 8 degrees C for 24 hours and then recovered for 36 hours, the effect was the best, the mitotic index was significantly increased to 11.3%. CONCLUSION: The low temperature could obviously influence the cell synchronization division in suspension culture cells of P. ternata, and the mitotic index was efficiently increased.

[Infection progress of arbuscular mycorrhizae on tissue-cultured plantlets of Pinellia ternata].

OBJECTIVE: To study the Arbuscular mycorrhizal (AM) formation progress and infection characteristics between tissue culture plantlets of Pinellia ternata and Glomus mosseae. METHOD: The tissue culture plantlets of P. ternata were inoculated with G. mosseae, the formation of AM were sampled and observed with microscopy by staining. RESULT AND CONCLUSION: The hyphae of G. mosseae began to penetrate the root epidermis after 10 days of inoculation. Lots of intracellular hyphae formed in cortex cells at the 15th day. Arbuscules started to form and there were some hyphae on the root at the 20th day. At the 25th day, many arbuscules formed and most as Arum type. Some arbuscles started to disintegrate at the 30th day, and a few of vesicles occurred. Lots of spores formed after 35 days. At the 40th day, some vesicles began to decline. The hand section showed that the intercellular hyphae gradually formed in intercellular space, and the hyphae branched in cortex cells and occupied most cell lumen finally. It is expounded that P. ternata and G. mosseae could recognize each other quickly and form a symbiont system.