樟树幼苗对干旱胁迫和种植密度的生理响应

Physiological responses of Cinnamomum camphora seedlings to drought stress and planting density

以1年生樟树(Cinnamomum camphora)实生苗为试验材料,通过自然干旱的方法人工模拟干旱胁迫环境,研究不同种植密度下(10、20、40、80株·m^(-2))幼苗对干旱胁迫各个时期(4、8、12、16、20 d)的生理响应,确定樟树对幼苗干旱和不同种植密度的响应机制。结果表明,各密度幼苗叶片的相对含水量随干旱胁迫时间的延长而下降,在各干旱胁迫阶段的下降幅度随密度的增加而加大;除10株·m^(-2)幼苗外,其他密度幼苗的叶片叶绿素含量随干旱时间的延长先升后降,变化幅度随着密度的增加而增大;各密度下的幼苗叶片可溶性糖含量、可溶性蛋白质含量和SOD的活性均随干旱时间的延长而上升,幼苗叶片的脯氨酸和丙二醛(MDA)含量趋于上升,上升幅度随密度的增加而加大。总体来看,樟树幼苗抗旱能力随着密度增加而下降。

In order to understand the mechanism of physiological response of plants to drought stress, one-year-old Cinnamomum camphora seedlings with different planting densities （ 10, 20, 40, 80 seedlings ·m^-2） were grown in drought stress environments by manual simulation, and their physiological indices were determined at 4, 8, 12, 16, 20 d after drought stress. The results showed that the water content of seedlings under drought stress decreased with the extension of drought duration and the decrease amplitude increased with increasing planting density in each drought stage. The chlorophyll content of seedlings except for the density of 10 trees ~ m-2 in- creased and then followed by a decrease with increasing plitude increased with increasing density. Soluble sugar, drought duration, and the variation am- soluble protein contents and SOD activi- ty of seedlings under different planting densities increased with increasing drought duration, whereas their proline and MDA contents tended to increase, and the variation amplitude of these indices increased with increasing density. Generally, the drought resistance of C. camphora de- creased with increasing density of seedlings