Effect Of ⁶⁰Co-γ Irradiation On Sedum Spectabile Bareau And Analysis Of Variant

Sedum spectabile Bareau is a perennial plant in the stonecrop family, Crassulaceae, alias: scorpion grass. S.spectabile Bar. is widely applied in the garden landscape design because of the advantages of its strong resistance, low maintenance cost and lush growth.S.spectabile Bar. was combined with ⁶⁰Co-γray to determine the irradiation dose of inducting plant variation in the experiment of induced mutation breeding. The irradiation effects on S.spectabile Bar. induced by ⁶⁰Co-γray were analyzed, of which the morphological changes, physiological indicators (chlorophyll content, SOD, POD, CAT activity) and leaf stomatal morphology were observed utilizing by morphology, physiology, cytology principle. The genetic diversity of mutant was analyzed by ISSR molecular markers and cluster analysis methods. The research results indicated that:(1) The relationship is close on the choice of plant irradiation parts and the radiation sensitivity. The radiation sensitivity of the upper stem is better than the lower one.The upper stem is the best irradiation induced part.(2) The semi-lethal (LD50) is approximately 100Gy. The most appropriate dose of induced S.spectabile Bar. mutants is 50 Gy.(3) There are four mainly production ways after mutants or variant branches of S.spectabile Bar. were irradiated. To a certain extent, the top single-branch with branches formation happened; A lot of branches grew on the trunk, however, the top stopped to grow; Several branches emerged from the same place; A new generation of mutant M1 grew after the ground plant dead.(4) The characteristics variation of plant early performed in the aspect of leaf type, plant type, flower type. The variability in the leaf showed blade asymmetry, color white or yellow striped, twisted, concave or crack tip, two veins, etc.; The variation of plant type showed plants dwarf, internodes short, diameter large, multiple branches etc.; The variation of flower type showed large diameter, dark color, the increased number of petals variability and extended the flowering period.(5) Between chlorophyll and radiation dose emerge a negative correlation; With the increase of radiation dose, SOD, POD activity increased first and then decreased; CAT activity at 30Gy dose increased to activity peak and then decreased, slightly from 70Gy to 100Gy.(6) Irradiation significantly affected the leaf stomatal morphology: the leaf stomatal aperture of 50Gy variation plants were larger than others.30Gy plant sank seriously, the stoma kept closed.(7) Establishing a satisfactory ISSR-PCR reaction system for S.spectabile Bar.firstly: 20μl reaction system contained 10×PCR Buffer (Mg2+free) 2.0μl, 2mmol/L dNTPs, 750nmol/L primer 25ng template DNA, 1.0U Taq DNA polymerase, 2mmol/L Mg2+.Amplification program included predenaturation at 94℃for 7min; denaturation at 94℃for 45s, annealing at 52℃for 1min, extend- ing at 72℃for 1.5min, after 35cycles; the product was extended at 72℃for 4min.(8) The similarity coefficient among plants were 0.5805⁰.7886 and the average similarity coefficient was 0.6846. The genetic similarity of the mutations was identified and analyzed by using the method of ISSR technology, and high ornamental value plant M0-1, M0-2, M0-3, M0-4 and M0-5 were selected.