北方森林频繁缺水对优势树种的影响日益受到重视,特别是应对全球气候变化情景。然而,光强耦合和水分亏缺对落叶松幼苗再生和生长的影响,中国北方森林的优势物种,还不清楚。我们用四种光强度(自然阳光,50%阴影,75%的阴影,和90%的阴影)和三种土壤水分条件(80%,60%,和40%土壤饱和含水量)。结果表明,光水耦合对兴安落叶松幼苗的生长发育有显著影响。在40%的饱和土壤水分含量,净光合速率,蒸腾速率,叶绿素a,在80%的土壤饱和含水量下,总酚叶明显低于相同的光照条件。在60%土壤饱和含水量和50%遮荫处理的耦合处理下,植物高度增量,净光合速率,气孔导度,蒸腾速率,叶绿素a,和酚类化合物含量显著高于其他耦合处理;然而,超过75%的遮光抑制了光合参数,叶绿素a,总黄酮叶,和总黄酮分支。本研究结果对森林经营实践具有重要的启示意义,为落叶松幼苗在光水耦合下的早期生长、促进幼苗的存活和生长提供了科学参考。
The impact of frequent water deficits on dominant tree species in boreal forests has received increased attention, particularly towards addressing the global climate change scenarios. However, the impacts of coupled light intensity and water deficit in the regeneration and growth of Larix gmelinii seedlings, a dominant species in
China\'s boreal forests, are still unclear. We conducted a dual-factor controlled experiment with four light intensities (natural sunlight, 50% shading, 75% shading, and 90% shading) and three soil water conditions (80%, 60%, and 40% soil saturated water content). The results showed that the coupling of light and water has a significant effect on the growth and development of Larix gmelinii seedlings. In 40% of the saturated soil moisture content, net photosynthetic rate, transpiration rate, chlorophyll a, and total phenol-leaf were significantly lower than the same light conditions under 80% soil saturated water content. Under the coupling treatment of 60% soil saturated water content and 50% shading treatment, the plant height increment, net photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll a, and phenolic compound content were significantly higher than those of other coupling treatments; however, more than 75% shading inhibited photosynthetic parameters, chlorophyll a, total flavonoid-leaf, and total flavonoid-branch. Our results have important implications for forest management practices; they provide a scientific reference for the early growth of Larix gmelinii seedlings under the coupling of light and water and promote the survival and growth of seedlings.