以1年生火炬树苗木为试验材料,采用称重控制土壤含水量的方法,设置对照(CK)、轻度水分胁迫(T1)、中度水分胁迫(T2)和重度水分胁迫(T3)4个不同处理组,研究火炬树幼苗的生长和生理特征差异。结果表明:对照组CK火炬树幼苗的株高、基径、生物量积累(叶质量、茎质量和根质量)、主根长度及第一级侧根数量显著高于T2和T3,轻度胁迫(T1)对茎质量和总生物量影响不显著,而显著降低了叶质量和根质量;水分胁迫下,火炬树幼苗Pn和Tr显著降低,抑制了火炬树幼苗生物量积累和火炬树幼苗的根生长,通过提高水分利用效率来提供生长所需要的水分来适应水分胁迫;此外,整个胁迫期间,3个水分胁迫组的脯氨酸含量始终显著高于对照CK,在渗透调节作用中起非常重要的作用;水分胁迫初期导致叶绿素含量增加,提高了水分胁迫的适应能力;由于胁迫初期的抗旱锻炼,胁迫30d后,3个水分胁迫组的MDA含量显著低于对照。胁迫后期水分胁迫导致叶绿素含量降低,同时MDA含量与对照相比又有所增加,但增幅不大,说明伤害程度较小。
Using pot culture 1-year-old Rhus typhina seedlings as experiment materials and adopting the method of weighing the soil to control the water content,four different levels of water stresses were applied to examine the effect of water stress on the growth and eco-physiology of R.typhina seedlings. The water stresses were the control(CK)、mild water stress(T1)、moderate water stress(T2) and severe water stress(T3).The results showed that height, root collar diameter, biomass accumulation (expressed as total biomass and weight of needles, stem and shoots and roots), taproot length, number of first-order lateral roots of R.typhina seedlings in group of CK were obviously higher than those of group T2 and T3,In group T1 of R.typhina seedlings did not effect Stem weight and total biomass,but seriously decreased shoots and root weight;R.typhina seedlings under extremely low water supply exhibited notably reduced net photosynthetic rate and transpiration rate,which restricted their biomass accumulation and root growth of R.typhina seedlings,while R.typhina seedlings could acclimate to the water regimes by adjusting their water use efficiency. In the whole water treatment period,in group of T1、T2 and T3 had higher content of proline than that of group CK,which had a important function in infiltration modulation. Content of chlorophyll of R.typhina seedlings increased at the beginning of water treatment,it enhanced the compliant ability of water regimes. Because of R.typhina seedlings kept fighting a drought at the beginning of water treatment,after 30 days of water stress,in group of T1、T2 and T3 had lower content of MDA than that of group CK. At the later period of water stress,in group of T1、T2 and T3 of R.typhina seedlings, content of chlorophyll decreased,and content of MDA was a bit higher than that of group CK,which indicated that R.typhina seedlings had less damage.
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