不同外源激素对甘蓝型油菜'农大1号'和'中双11'农艺性状及生理特性影响研究OA

To investigate the regulatory mechanisms of exogenous hormones on early maturation in Brassica napus,two cultivars,'Nongda No.1'and'Zhongshuang 11',were utilized as experimental materials.Plants at the 5-6 leaf stage were treated with foliar sprays of brassinosteroids(BR),gibberellic acid(GA3),or 1-naphthaleneacetic acid(NAA),with a distilled water spray serving as the control.Agronomic traits and physiological indicators were analyzed 7 days after treatments.The application of BR,GA3,or NAA promoted pre-winter rapid growth,resulting in reduced leaf length and width but increased root and stem thickness.Notably,NAA treatment significantly enhanced plant height in'Nongda No.1'.At harvest,all hormone treatments increased final plant height.Moreover,NAA and GA3 significantly shortened the time to maturity,with'Nongda No.1'maturing 7 days earlier and'Zhongshuang 11'maturing 5 days earlier compared to the control.The NAA treatment also positively influenced yield-related traits by increasing pod length and seed number per pod,while reducing glucosinolate content.Physiological analyses revealed that 7 days after treatments,NAA significantly elevated leaf catalase(CAT)activity,with'Zhongshuang 11'exhibiting the highest level(356.80 μmol/g).During the bolting stage,leaf CAT activity in'Nongda No.1'exceeded that of the control across all treatments except NAA.Conversely,NAA treatment significantly enhanced stem CAT activity,reaching 1.3-fold(146.31 vs.111.82 μmol/g)and 1.6-fold(135.89 vs.87.14 μmol/g)of the control levels in'Nongda No.1'and'Zhongshuang 11',respectively.BR treatment significantly increased the malondialdehyde(MDA)content in'Nongda No.1'after 7 days,which gradually decreased during the bud-to-spike stage.At the spike stage,GA3 treatment resulted in an MDA content twice that of the control,while NAA increased leaf MDA content to 1.9 times the control level.Both NAA and GA3 treatments significantly enhanced peroxidase(POD)activity during the bud-to-spike stage,reaching 1.6-fold and 2.3-fold of the control,respectively.Superoxide dismutase(SOD)activity in'Nongda No.1'leaves increased 7 days after treatment.During the budding and stem elongation stages,'Zhongshuang 11'exhibited enhanced SOD activity in leaves under GA3 treatment.However,SOD activity in both the leaves and stems of GA3-and BR-treated'Zhongshuang 11'plants was lower than in the control during this period.In conclusion,the foliar application of NAA,GA3,and BR enhances stress tolerance and promotes early maturity in rapeseed.NAA enables both leaves and stems to better withstand stress,while NAA and GA3 exert a more pronounced effect on stem elongation.The period 7 days after application represents a critical phase for these hormonal regulations of plant growth and development.