Development For The Library Of Mutants And The Analysis For Photosynthesis Of Leaf Mutant In Brassica Napus L.

Seeds of Brassica napus L. variety Gaoyou 605 were induced by 800Gy ⁶⁰Coγ-ray irradiation and 0.4% EMS (Ethyl Methan Sulfonate). The offspring of mutants with imitative traits for plant type, leaf, bloom, anthesis and pod were screened and identified in field. Cotyledon and seed embryo traits were also screened with hydroponics culture. The photosynthetic rate of leaf mutants with color or shape variation was detected and the rule of photosynthetic rate of mutant in different developing phases was disscussed, the observation of some nuclear and cytoplasmic male sterile lines of mutant was performed. The mutant library/population of Brassica napus including different types of mutants with variated traits was developed in present library. It will provide the important germplasm for further study of genome functions and breeding in rapeseed. The main results were showed as follows:Through screen and identification of morphology in M₃ and M₄, respectively, many mutants with mutative traits of plant were found. Among them, 11 mutations were leaf variations, including light-green leaf, deep-green leaf, durative yellowish leaf, temporary yellowish leaf, inlaid yellowish leaf, wrinkly leaf, curly leaf, peduncular-shaped leaf, round leaf and larger leaf; 9 were mutations on plant type, including excessive branches, lacking branches, highness, dwarf-like, erect posture, reclinate posture, strong stalk, slender stalk, wrinkled plant, purple stalk; 9 were flower variations, including dense flowers, light-yellow petals, white petals, wrinkled petales, narrow petals, larger petals, smaller petals, apetalous flowers, variable-numbered petals, fertile pistil protraction, sterile pistil protraction and multi-anther; and 6 were physiologic mutants, including genic male sterile (GMS), cytoplasmic male sterile (CMS), bud-dead, and early , later bloom. The morphology of these mutants showed that these mutative treats could be stably inherited.The total frequencies of seedling with mutative traits in 2006 and 2007 were 14.33% and 15.42% observed in hothouse, respectively. Among them, the frequencies of mutants with embryo number were 5.49% and 0.42%, respectively. Light-yellow cotyledon yellowish cotyledon, trump-shaped cotyledon, multilobed cotyledon, non-cotyledon, singlele-coty, tricotyledon and quadrcotyledon mutants appeared in both years with high frequencies, while none of these mutants was found in CK (wild type). These results showed that these mutative treats were controlled by genes, and could inherit from different generations. The farther observation and identification are needed for these mutants of seedlings.The photosynthetic rate on 11 leaf mutants with color variation and 7 leaf mutants of shape was detected in the bolting stage, initial bloom stage, florescence stage and mature stage. The results showed that there were distinct differences between leaf mutants and CK (wild type) in four different stages, exect dark green leaf mutant, the photosynthetic rate of the rest mutants was lower than that of CK (wild type). The photosynthetic rate of the inlaid yellowish leaf mutant was analysed in four phases on the whole yellow site, part yellow site and normal site. It indicated that the photosynthetic rate of whole yellow site was lower than other sites.