Genetic Relationship Of Three Species In Bauhinia By SRAP Analysis And Discussion Of ⁶⁰Co-? Radiation Mutagenesis On Bauhinia Purpurea

Bauhinia purpurea L.,Bauhinia variegata L.and Bauhinia blakeana Dunn are three famous ornamental trees of Bauhinia L.They are all of great horticul tural value in urban landscape, In this study, Sequence—related amplified polymorphism?SRAP? were used to identify the genetic relationship of the above three species based on the classification and selection with flower color of putative parental species,B.Purpurea L. and B.variegata L.Besides,we also use ⁶⁰Co-? radiation to mutagen the seeds of B.Purpurea L.to explore the varied biological effect caused by the different radiation doses,Through Observations of seeds germination rate, branches, leaves, plant height growth,observation slides of chromosome of root tip,MAD, chlorophyll and soluble protein,combined with SRAP moleular marker-assisted detection technology,The results were as follows:?1? Genetic relationship of the three species based on the classification and selection with flower colorSRAP marker could effectively distinguish the three species, and could prove the parents of B.blakeana L.are B.Purpurea L. and B.variegata L.at level of genetic molecules; Compared to B.Purpurea L., B.blakeana L. Share higher genetic similarity and shorter genetic distance with B.variegata L.; There may be a closer genetic relationship between dark purple flower B.variegata L., pink B.Purpurea L.and B.blakeana L.?2? Suitable radiation dose selection of B.Purpurea L.seedsB.Purpurea L.appeared inhibit phenomenon in germination percentage. in radiation dose of50 Gy and 150 Gy treatment. Seedling growth rate and height of 50 Gy and 150 Gy treatment groups was higher than that of 0Gy control group. Germination percentage. seedling rate,plant height showed clearly inhibition in 300 Gy treatment group, seeds in 600 Gy and1000Gy treatment groups could not alive in subsequent seeding experiment.Above all, we can determine the suitable radiation dose of B.Purpurea L. Seeds is150Gy³00Gy.?3? The mutation effect of⁶⁰Co-?radiation to the growth of B.Purpurea L.Through the continuing field observation, we found that the plant height, average section,Leaf length and width,were promoted by comparing the growth of treatment group50 Gy,150Gy with the control group 0Gy.showing the biological effects of low-dose radiation on plant growth, While,each the growth of each group differed from month to month, Leaf variation of 150 Gy treatment group generated more different kinds of type and number of leaves.which, were significantly higher than the control group 0Gy and 150 Gy treatment group, The plant height, internode length, leaf area of treatment group 300 Gy showed a negative inhibition compared to control group.?4? The mutation effect of ⁶⁰Co-? radiation to the root-tip cell of B.Purpurea L.Among the observed five groups of 0Gy, 50 Gy, 150 Gy, 300 Gy, 600 Gy chromosomes in root tip cells, the mutation rate varied from 0.45%-14.84%; 0Gy, the lowest rate was0.43%. 600 Gy,the largest, 14.84%.⁶⁰Co-?radiation caused B.Purpurea L.seed root tip cells produce a variety of types of aberration, including: micronucleus chromosome phenomena in each period, chromosome bridge, chromosome fragment, chromosome blocking phenomenon. micronucleus chromosome appeared higher frequency than other types in these experiments. the phenomenon of chromosomal aberrations rate increasing along with the increasing of radiation dose.?5? The mutation effect of Co-? radiation to the physical activity of B.Purpurea L.With the increasing of radiation dose, soluble protein contentis reduced, and the decrease in150 Gy treatment group between the Control group was significant, indicating that radiation had some influence on the physiological activity of plants.MDA vitality showed decline trends, differences between 150 Gy treatment group and the 0Gy control group was significant, indicating that oxidation of the B.Purpurea L.cell membrane was reduced,it means the plant has enhanced resistance characteristic. The content of chlorophyll b varied little, chlorophyll a content increased along with radiation dose, it may be related to the overall plant resistance increasing phenomenon.?6? The mutation effect of⁶⁰Co-?radiation to the genetic diversity of B.Purpurea L.In Treatment group of 50 Gy,150Gy and control group 0Gy, The genetic identity becomes smaller with the increase of radiation dose,the genetic distance were increasing with the radiation dose; At the genetic similarity coefficient of 0.75,there were two types of punishment. Category includes all ten 0Gy control group individuals and seven of ten in treatment group 50 Gy, the second category includes three of ten in treatment groups and all ten 150 Gy treatment groups, indicating that SRAP molecular markers can prove that ⁶⁰Co-?rays could made genome of mutationat in B.Purpurea L. at molecular level, the mutation is random, and the degree of variation of radiation was positively correlated dose.