【摘 要】
：
该文通过室内模拟实验研究了中国干旱草原牧业生产常见的两种代表性牧草苜蓿和羊草在盐渍环境中,不同的水分条件下盐分(Na,Cl)对其生长的影响,探讨了盐渍化土壤-牧草系统盐分
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该文通过室内模拟实验研究了中国干旱草原牧业生产常见的两种代表性牧草苜蓿和羊草在盐渍环境中,不同的水分条件下盐分(Na<+>,Cl<->)对其生长的影响,探讨了盐渍化土壤-牧草系统盐分(Na<+>,Cl<->)对养分(N,P,K<+>,Ca<2+>,Mg<2+>)吸收的影 响及牧草的适应性反应,研究表明:在定水位供水和蒸发脱 湿两种水分条件下,NaCl胁迫都造成羊草和苜蓿株高降低,蒸散量减少,相对生长率(RGR)降低,产草量下降.在土壤脱 湿条件下,羊草和苜蓿生苌受到水分和盐分双重胁迫的影响,随盐度水平(NaCl 25-300 mmol/L,总盐0.17-0.68﹪)的增加,羊草株高日增长量和相对生长率显著减少,蒸散强度减弱 ,但总累积蒸散量增加,存活天数延长,抵御土壤干旱的能力明显增强.苜蓿在土壤脱湿条件下,株高日增长量和相对生长率受盐分抑制明显,土壤盐分较低(NaCl 25-125 mmol/L, 总盐0.17-0.34﹪)时,盐分对苜蓿的存活天数和累积蒸散量影响不大;土壤盐分较高(NaCl 215-300 mmol/L,总盐0.51-0.68﹪)时,随盐度的增加,存活天数显著减少,累积蒸散量降低.脱湿土壤中,羊草钾钠吸收选择性在NaCl 25-225 mmol/L,(土壤总盐0.17-0.53﹪), 随盐度处理水平的增加而增强;NaCl 275-325 mmol/L(总盐0.63-0.73﹪),钾钠吸收选择性逐渐降低.NaCl 25-175 mmol/L(土壤总盐0.17-0.44﹪),羊草钾钠运输选择性,随盐度处 理水平的增加而增加;NaCl 225-325 mmol/L(土壤总盐0.53-0.73﹪),钾钠运输选择性逐渐减弱.苜蓿根系对钾钠吸收的选择性,NaCl 25-225 mmol/L(土壤总盐0.17-0.44﹪),随盐 度处理水平的增加而增大,NaCl 225-325 mmol/L(土壤总盐0.53-0.73﹪)显著减小;钾钠运输选择随盐度增加明显减小.
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