外源喷施油菜素内酯对碱胁迫下大麦种子萌发的影响

Effect of Exogenous Brassinosteroids on Barley Seeds Germination under Alkaline Stress

为探讨外源油菜素内酯(Brassinosteroids,BR)对碱性盐胁迫下大麦种子萌发过程形态特征,揭示大麦种子的萌发特性及其化学调控,以黄长芒大麦品种为试材,利用0、40、60、80、100 mmol·L^(-1)的NaHCO3+Na2CO3(摩尔比为9∶1)溶液培养大麦种子进行萌发试验,确定大麦种子萌发的耐碱胁迫适宜浓度、半致死浓度和极限浓度。用不同浓度的BR(0.01、0.05、0.10 mmol·L^(-1))配制碱性盐溶液,并在25℃、12 h/20℃、12 h的白天/黑暗条件下培养,以75 mmol·L^(-1)的NaHCO3+Na2CO3(摩尔比为9∶1)模拟碱胁迫,在培养第3 d统计发芽势,第7 d统计发芽率,并取样测定地上、地下形态指标。结果显示:碱胁迫下大麦种子的萌发受到显著抑制,至100 mmol·L^(-1)碱处理时,大麦种子的萌发率仅为对照的一半,为55.83%,发芽势仅为对照的1/3;0.01 mmol·L^(-1)的BR处理对碱胁迫引起种子萌发抑制的缓解效果最佳,具体体现为种子的发芽势、发芽率和发芽指数都高于对照的1倍以上(P<0.05);外源BR处理对缓解碱胁迫下大麦种子根和幼苗的抑制效果以0.05 mmol·L^(-1)和0.01 mmol·L^(-1)为最佳。外源BR可调节大麦种子萌发期的萌发特性和苗期生长特性,提高其对碱胁迫的抵抗能力,促进种子的萌发与生长。

To investigate the morphological characteristics of barley seed germination under alkaline-salt stress and exogenous brassinosteroids(BR)and reveal the germination characteristics and chemical regulation of barley seeds,seeds of barley cultiva‘r Huangchangmang’were cultured with 0,40,60,80 and 100 mmol·L^(-1)NaHCO3+Na2CO3 solution(molar ratio 9∶1),as well as the germination rate was selected to determine the suitable alkali tolerance concentration,semi-lethal concentration and limiting concentration.Alkaline-salt solutions were prepared with 0.01,0.05 and 0.10 mmol·L^(-1)BR solution,and barley was cultured at 25℃for 12 h(day)and 20℃for 12 h(night)with 75 mmol·L^(-1)NaHCO3+Na2CO3(molar ratio 9∶1),the germination potential was counted on the third day,as well as the germination rate,the above-ground and under-ground morphological indexes were counted on the seventh day.Results showed that the germination of barley seeds was significantly inhibited under alkali stress,and the germination rate was only half of that of the control(55.83%)under 100 mmol·L^(-1)alkali treatment,as well as the germination potential was only 1/3 of that of control.Treatments with 0.01 mmol·L^(-1)BR had the optimal effect of inhibiting germination,and the germination potential,germination rate and germination index of barley seeds were higher than those of control by one times(P<0.05).The best inhibiting effect of exogenous BR on alleviating alkali stress was 0.05 mmol·L^(-1)(roots)and 0.01 mmol·L^(-1)(seedlings),respectively.Hence,exogenous BR can improve barley resistance to alkali stress and promote seed germination and growth through regulating the seed germination characteristics and seedling growth characteristics.