Effects of Artificial Shading and Plant Density on Corymbia Citriodora Seedling Characteristics

Abstract The objective of this work was to evaluate the influence of colored shade mesh and plant density on the morphological characteristics of Corymbia citriodora seedlings. The highest radiation efficiency was found in the blue mesh, 7.01 g MJ-1 and 5.72 g MJ-1 for average and high density respectively. For dry matter and leaf area index at high density, the treatment without mesh followed by the red mesh was the best. The chlorophyll index did not differ between treatments, with mean values of 206.4, 59.1 and 262.0 for chlorophyll a, b and total, respectively. Using principal component analysis, we found the total variance to be 70%. The use of colored shade mesh and plant density altered the radiation use efficiency and dry matter accumulation. Leaf area index was affected only by plant density. The red mesh resulted in the most similar values to the treatment without mesh.

摘要 本研究旨在评估有色遮阳网（colored shade mesh）与种植密度对柠檬伞房桉（Corymbia citriodora）幼苗形态特征的影响。蓝光遮阳网下的辐射利用效率（radiation use efficiency）最高，在平均密度与高密度下分别为7.01 g·MJ⁻¹和5.72 g·MJ⁻¹。针对高密度下的干物质（dry matter）积累与叶面积指数（Leaf Area Index），无遮阳网处理表现最优，其次为红色遮阳网处理。各处理间的叶绿素指数无显著差异，叶绿素a（chlorophyll a）、叶绿素b（chlorophyll b）及总叶绿素的平均值分别为206.4、59.1和262.0。通过主成分分析（Principal Component Analysis），本研究发现总方差解释率达70%。有色遮阳网的应用与种植密度均可改变辐射利用效率与干物质积累量。叶面积指数仅受种植密度的影响。红色遮阳网处理下的各项指标与无遮阳网处理最为接近。