【摘要】 以1月龄巨尾桉组培苗为材料,通过模拟雨季和旱季的土壤水分条件试验探讨干旱胁迫下巨尾桉幼苗形态的可塑性及生理响应特征。结果表明:与高水和中水处理相比,低水处理(13%左右土壤体积水分含量,模拟旱季土壤水分)导致巨尾桉幼苗生物量减少,叶片形态发生明显变化,总叶面积、叶片数、平均叶面积和比叶面积减少,而且叶片可溶性糖含量增加;但水分胁迫下巨尾桉生物量分配模式不变,叶片脯氨酸含量变化也不明显,叶片最大光化学量子效率(Fv/Fm)仍维持在正常水平。研究发现,干旱并未对巨尾桉光合能力和水分吸收策略造成过多影响,巨尾桉能通过限制生长、减少水分消耗来应对干旱胁迫,保证植株安全度过干旱同时又不会过度消耗当地环境水分,以利于维持当地旱季的水分平衡。更多还原

【Abstract】 The effect of simulated soil moisture gradient on phenotypic plasticity and physiological responses of Eucalyptus grandis×E.urophylla seedlings was studied in this paper.One-month-old seedlings were grown under high/medium/low soil moisture condition(high/medium/low water treatment,HW/MW/LW) in greenhouse.Compared with HW and MW,under LW(about 13% volumetric soil water content) treatment,the biomass,total leaf area,average leaf area,leaf number and specific leaf area were significantly lower,while the content of foliar soluble sugar was obviously increased.The change of biomass allocation and free proline content were not obvious,optional/maximal photochemical efficiency of PSⅡ still maintained a normal level.The results indicated that drought had less effect on the photosynthesis and water absorption of E.grandis×E.urophylla seedlings.E.grandis×E.urophylla adapt drought stress by limited growth and decreased water consume.This strategy might allow E.grandis×E.urophylla seedlings to survive through the dry season,which is advantageous to maintain the water balance in the local area.更多还原