A Study Of Mutagenic Effects On The Seeds Of Phyllostachys Heterocycla Cv. Pubescens

Due to the uncertainty of flowering time and space, as well as the characteristic that large-scale plants would die after flowering, the process of conventional breeding such as sexual hybridization for Phyllostachys heterocycla cv. Pubescens has been restricted to a large extent. We study on its mutation breeding in order to establish a strategy for bamboo genetic improvement and obtain good mutants bred new varieties for direct use or as germplasm resources for indirect use in a short period of time, which provide theoretical basis for the establishment of mutagenesis system and mutation breeding. Dry seeds are carried into physical, chemical, and physical and chemical mutagenesis treatment for the research on the differences between a set of parameters of physiological metabolic activity in seed germination period, morphology of seedlings and the adult plant chlorophyll fluorescence characteristics. The main findings are as follows:1 The sensitivity to different mutagenic treatment of Phyllostachys heterocycla cv. Pubescens is higher than other plants in Gramineae.2 The impacts of the same mutation on different characters differ from each other. Principal component analysis shows that germination rate and seedling height after different mutagenesis treatments are the leading factors, and both of them have a significant correlation; the analysis of the indicators measured at different growing stages shows that the mutagenic effects caused by different mutagenesis had not completely disappeared. They affect the process of growth, photosynthetic efficiency, as well as morphological features, and the possibility of hereditability for such an effect remains to be further explored.3 The impacts of different mutagenesis treatments on the same character differ from each other. A comprehensive analysis of mutagenic effects reflected by the four dominant factors of the rate of germination, seedling height, total chlorophyll, and qP shows that the effect of NaN₃ on other indicators except the seedling height is more significant between the two types of chemical mutagens. The mutagenic effect of chemical mutation on the adult plants is smaller than that ofγ-ray irradiation. The impact of compound mutation on different characters with a more significant extent than the single mutation expresses inhibitory.4 The mutagenic effects under the same mutation in different doses or concentrations differ from each other. In the low-dose range, the bamboo suffers from less physical damage with a high aberration rate. The dose of 10Gy for theγ-ray irradiation and 0.05% of EMS treatment have a promoting effect on the height growth. Principal component analysis shows low doses ofγ-ray irradiation and NaN₃ treatment express positive effects, while the high doses express negative effects. As for EMS treatment, 0.4% is the appropriate concentration for the expression of mutagenic effects. Compound mutation shows the negative effects.