苗期施用外源植物激素对甘蓝型油菜生长发育与产量形成的影响OA

Two rapeseed cultivars,'Xiangzayou 787'and'Fanming Youtai'(Brassica napus),were used as experimental materials.Four exogenous hormones,namely brassinolide(2,4-epibrassinolide,BR),melatonin(MT),abscisic acid(ABA),and naphthalene acetic acid(NAA)were sprayed on the leaves at the seedling stage to analyze their effects on agronomic traits,yield components,physiological characteristics and the expression of growth-related genes.The results showed that,for'Xiangzayou 787',treatment with 20 μmol/L BR exhibited the best effect,and the yield per plant was 25.94%higher than that of the control(sprayed with water),followed by 20 mg/kg NAA,with the yield per plant increasing by 20.44%compared to the control.For'Fanming Youtai',60 mg/kg NAA showed the best effect,with the yield per plant increasing by 26.13%compared to the control,followed by 20 μmol/L BR,with the yield per plant increasing by 25.53%compared to the control.Treatment with 20 μmol/L BR increased the yield,leaf length,leaf width,plant height and the number of effective siliques of both cultivars.The activity of superoxide dismutase(SOD)in leaves and flowers initially increased and then decreased during the growth period,while the content of malondialdehyde(MDA)decreased and then increased.The CAT activity in flowers showed an overall upward trend,with significantly higher values in some treatments than in the control.The MDA content in the flower buds was significantly lower than that in the control.In leaves,the expression levels of BnaA02g27460D in both cultivars generally increased,peaking at the flowering period.In the floral organs of'Fanming Youtai',the expression level of BnaA02g27460D first decreased and then increased,reaching its lowest level in fully opened flowers.In leaves at the bud stage,the expression level of BnaA02g27460D was significantly lower than that in the control.Correlation analysis indicated that the MDA content in leaves of'Xiangzayou 787'at the bud stage was significantly correlated with the expression level of BnaA02g27460D and the yield per plant.The CAT activity in leaves at the flowering stage was also significantly correlated with the expression level of BnaA02g27460D and the yield per plant.The activity of peroxidase(POD)in the leaves of'Fanming Youtai'at the bud stage was significantly correlated with the gene expression levels of BnaA02g27460D and BnaA10g08770D,as well as the yield per plant,indicating that the related physiological indices and gene expression levels may be involved in the regulation of growth,development and yield formation of rapeseed by exogenous hormones.