Physiological And Genetic Characteristics Of The Glucosinolate Content In Brassica Napus

The glucosinolate trait is one of the key quality indexes in rape seeds.The glucosinolates in residues of rape seeds can produce some harmful substance with the help of hydrolases,which might make livestock poisoned and values of the residues lowered and their uses limited in feed industry.The glucosinolates in rapes might often be beneficial for the ecological environment.The rapes with high glucosinolate content keep greater power to resist pests,disease and adverse environment.For the good use of the glucosinolate trait,the experiment was carried out to study physiological and genetic characteristics for two groups of rape strains with different glucosinolate content.The results were as follows:(1) The glucosinolate content in leaves and seeds maintained dynamic changes at different growth stages.The leaves of high glucosinolate lines kept the most glucosinolate content at seedling stage.The most glucosinolate content in leaves of 967H was 29.08μmol.g^-1,and it in 246009-2 was 32.50μmol.g^-1.The glucosinolate content in leaves of high glucosinolate lines decreased until the fully flowering stage, then increased until fruitâ…¡stage,and then decreased from fruitâ…¡stage to fruitâ…¤stage.The leaves of low glucosinolate lines kept the most glucosinolate content at budding stage.The glucosinolate content in leaves of 967L was 16.94μmol.g^-1,and it in 04068-4 was 15.77μmol.g^-1.The glucosinolate content in leaves of low glucosinolate lines decreased from budding stage to stem elongation stage,increased from stem elongation stage to early flowering stage,then decreased from early flowering stage to fully flowering stage,and then increased until fruitâ…¤stage.The seed glucosinolate content was generally decreased at first and then increased.The seed glucosinolate content in high glucosinolates lines increased dramatically from fruitâ…¢stage to fruitâ…¤stage,while low glucosinolates lines increased only a little at late growth stage.At the seed developmental Stage,a negative correlation was kept between glucosinolate content in leaves and seeds.(2) The glucosinolate content in two parents,F₁,F₂,BF₁and F₃ seeds was analyzed to indicate that glucosinolate content in these seeds was not only controlled by both maternal genotypes and embryo genotypes.The glucosinolate content in F₁ seeds was mainly determined by maternal genotypes;and it in F₂ and BCF₁ seeds was affected by maternal genotypes less than F₁.With the increase of generations,the glucosinolate content in seeds was more affected by paternal genotypes,and it in F₃ seeds was mainly determined by plant genotypes.The glucosinolate content in either F₃ or RF₃ seeds formed a curve with a single peak.Chi-square analysis indicated that glucosinolate traits belonged to quantitative characters and separating ratio of high glucosinolate plants and low glucosinolate plants was 63:1 byχ² test,the amount of glucosinolate content was controlled by three pairs of dominant genes.(3)There was more soluble sugar,protein and free proline content in rape leaves at stem elongation stage and blooming stage.The soluble sugar and protein content in rape leaves was least at maturity stage,while free proline content in rape leaves was least at seedling stage.The components could played a important role on to keep more vigorously vegetative growth and reproductive growth at stem elongation stage and blooming stage,and to resist in chilling injury and other adversity.The rape leaves in high glucosinolate lines kept more soluble sugar,soluble protein and free proline content,while the rape leaves in low glucosinolate lines was opposite.The relative permeability of plaslemma and MDA content from seedling stage to maturity stage increased,while chlorophyll content kept decreasing after increasing.It was indicated that lipid peroxidation in plant cell maintained increasing gradually. The leaves in high glucosinolate lines kept less MDA content and relative permeability of plaslemma,and more chlorophyll content.During all the growth stages,the SOD,CAT and POD activities in all the rape strains kept decreasing after increasing.The rape leaves in high glucosinolate lines kept greater activities of SOD, CAT and POD,the rape leaves in high glucosinolate lines was opposite.(4) The experiment was carried out to study the effects of the treatment with different irradiation on rape strains with different glucosinolate content.The results indicated that the low glucosinolate line was more sensitive to 60Coγrays irradiation than the high glucosinolate line.The germination rate of treatments with 800Gy, 1000Gy or 1200Gy irradiation in 967L was larger significantly than 967H from the fifth day to the eighth day.The germination rate of these treatments of 967L at the fifth day was 8.5%,8.6%or 5.8%lower than 967H.The field Seedling survival rate of treatments with 800Gy,1000Gy or 1200Gy irradiation in 967L was 9.8%,19.8%or 20.1%lower than 967H.The same pose of irradiation had greater effect on M₁ and M₂ agronomic characteristics of 967L than 967H.The main agronomic characteristics of 967L could be changed significantly by the 800Gy irradiation,while the same effect occurred in 967H with the help of 1000Gy irradiation.(5) The irradiation had uncertain effect on quality traits,which was related with genotype,irradiation dose and index characteristics.Some quality indexes took place with positive effects,some indexes took place with negative effects,and others took place with positive or negative effects.With the use of the same pose of irradiation, the changed range of quality indexes and the number of mutant population in 967L were greater than 967H.The number of mutant population in 967L with treatment or 1000Gy irradiation was 2.63%—7.37%fewer than 967H.(6) Investigation and Sclerotinia sclerotiorum inoculation test were carried out to indicate that high glucosinolate lines had greater ability resisting in the disease than low glucosinolate lines.Whether Sclerotinia sclerotiorum was inoculated in plants or occurred naturally in the fields,the glucosinolate content had significant correlation with disease index,and their correlation coefficient was 0.8867^* and 09621^* respectively. The high glucosinolate lines kept greater activities of SOD,POD,CAT and PAL,and maintained fewer activities of PPO and MDA content at the seventh or eighth leaves stage.After Sclerotinia sclerotiorum inoculation,the MDA content and SOD,POD, CAT and PAL activities in leaves increased,but the PPO activity decreased.The high glucosinolate lines kept less increasing rate of SOD,POD,CAT and PAL activities and MDA content,and more decreasing rate of PPO activity than low glucosinolate lines.The result indicated that Sclerotinia sclerotiorum had greater effect on the protective system in high glucosinolate lines than low glucosinolate lines,and the increasing(or decreasing) rate of the protective enzymes was associated with susceptibility.(7) 482 RAPD primers were screened for polymorphic primers,and 6 RAPD primers were detected polymorphism between the parents.The high and low glucosinolate bulks were constructed by DNA of high glucosinolate individuals and low glucosinolate individuals in the F₂ through using BSA method.One RAPD primer was detected polymorphism were used to screen polymorphism for parents and two DNA bulks by PCR amplication.The primer S268 were detected polymorphism between two parents and two DNA bulks.The primer was used to screen the 126 lines in F₂ population.Variant analysis with a single mark indicated that the low glucosinolate traits of 29.51%were contributed by the S268_600bp mark.(8) 93 pairs of SSR primers were screened for polymorphic primers,and 8 pairs of primers were detected polymorphism for the parents.The high and low glucosinolate bulks were constructed by DNA of high glucosinolate individuals and low glucosinolate individuals in the F₂ through using BSA method.A pair of SSR primers was used to screen polymorphism for parents and two DNA bulks by PCR amplication.The pair of primers(CB 10364) was detected polymorphism between two parents and two DNA bulks.The pair of primers was used to screen the 180 lines in F₂ population.Variant analysis with a single mark indicated that the low glucosinolate traits of 34.36%were contributed by the CB10364_230bp mark.