干旱胁迫对水曲柳苗木细根颜色和直径的影响

目的]分析干旱胁迫下细根形态反应及其与根序发育的关系。方法]对干旱胁迫下水曲柳苗木1~3级根颜色和直径变化进行了研究。结果]①干旱胁迫下水曲柳苗木细根主要有白色、黄色、褐色及白色黑尖4种类型,较对照颜色复杂(对照仅有白色和黄色2种类型)。随胁迫时间延长,水曲柳苗木1~3级根中,1级根颜色变化最多(白色、黄色、褐色及白色黑尖),数量变化也最明显;2级根有3种颜色(白色、黄色、褐色),数量变化趋势与1级根相似;3级根仅有黄色和褐色2种颜色,与对照相比少了白色根,多了褐色根,随胁迫时间延长,褐色根比例明显增加。②干旱胁迫下1~3级根平均直径显著低于对照,1级根直径随胁迫时间延长降低最显著(P0.05),2、3级根直径也呈下降趋势,但只在胁迫30 d和40 d时显著小于对照(P0.05)。对照各级根直径变化均不显著。在胁迫过程中不同颜色细根直径变化趋势也有所差异。与对照相比,白色1级根直径随胁迫时间延长减小最为明显(P0.05)。2级3种颜色根直径到胁迫30 d时才显著小于对照(P0.05)。3级根黄色根在胁迫过程中直径变化不大。结论]干旱胁迫下水曲柳苗木1~3级细根的颜色和直径均发生了比较明显的变化。

Effect of Drought Stress on Root Color and Root Diameter of Fraxinus mandshurica Seedlings

Objective ] The fine root morphological reaction and its relationship with root .order development of Fraxinus mandshurica under drought stress were analyzed. Method] Color and diameter of the first to the third fine root of Fraxinus mandshurica seedlings were studied under drought stress. Result ] （1）There were 4 root colors under drought stress, including white ,yellow , borwn and white black tip, which more complex than that of the control （ only 2 types of white and yellow ） . During drought stress, the first order root color changed move obviously than that of the second and third order roots. （2） The diameters of the first to third order root under drought stress significantly decreased than those of control （P 〈 0.05 ）. The diameter of the first order root decreased significantly during the stress, but the diameter of the second and the third order root decreased only began after 30 days drought stress. There were no significant changes in root diameter of control. Compared with the control , the white first order root＇ s diameter decreased obviously under drought stress （ P 〈 0.05 ）. The diameter of the three color roots in the second order decreased only after 30 d stress （P 〈 0.05 ）. The diameter of the third yellow root had no change under drought stress. Conclusion] Color and diameter of the first to the third fine root of Fraxinus mandshurica seedlings changed obviously after drought stress.