干旱胁迫下白桦主要生理指标的变化及相互关系

Drought Stress-induced Responses of Physiological Indices of Betula platyphylla

以东北林业大学帽儿山实验林场的白桦全同胞子代幼树作为研究材料,通过测定干旱胁迫下样株叶片的生理指标,探讨了在不同施肥条件下白桦对干旱胁迫的反应。结果表明:在土壤干旱胁迫下,施肥处理和未施肥处理的白桦叶片相对含水量和叶片失水率下降,叶片相对电导率和丙二醛的量上升,可溶性糖和可溶性蛋白质量分数先上升后下降,叶片相对含水量与丙二醛的量和可溶性蛋白的质量分数呈显著负相关,非施肥处理可溶性糖质量分数与可溶性蛋白质量分数呈显著正相关。白桦叶片相对含水量、叶片失水率、相对电导率、丙二醛、可溶性蛋白的质量分数在施肥与不施肥2种处理间差异不显著,但进一步分析丙二醛的量和可溶性糖质量分数的变化发现,施肥处理的白桦幼树随着干旱时间的加长丙二醛的积累偏低,而可溶性糖的积累偏高,这意味着施肥处理的白桦相比之下可能对干旱胁迫有较强的耐受性。

An experiment was conducted to study the responses of physiological indices to soil drought stress under different fertilization conditions using the leaves from Betula platyphylla young trees of a full-sib family progeny in Maoershan Experimental Forest Farm of Northeast Forestry University as testing materials. Results showed that, under drought stress, the relative water content （RWC） and water loss rate of the leaves from both of fertilized and non-fertilized treatments decreased, the relative conductivity and malondialdehyde （MDA） content in leaves enhanced, and the contents of soluble sugar and soluble protein increased first and then decreased. There were significant negative correlations between RWC and MDA, as well as between RWC and soluble protein content in the leaves, and a positive correlation between the soluble protein content in fertilized treatment and the soluble sugar content in no-fertilized treatment. RWC, relative conductivity, MDA, soluble protein content of the leaves showed no significant differences between fertilized and non-fertilized treatments. Further analysis showed that the leaves in fertilized treatment had lower level of MDA accumulation and higher soluble sugar content compared with those in non-fertilized treatment with stress time prolonging. It is indicated that the birch young trees grown in fertilized soil exhibit higher drought tolerance.