Abstract: Eragrostis spectabilis (Pursh) Steud is a new ornamental grass in China. In order to explore the ecological adaptability of this species to the light regimes and optimal shading of growth, E. spectabilis was cultivated under four light intensity regimes for two years. The parameters of growth, photosynthesis and biomass were determined during the growth season. Results showed that plant height and crown breadth increased with the decreasing of irradiance, and plant height was the lowest under 90% shading during the second growth season. Tillers and seed yield significantly decreased, and chlorophyll content, leaf area, photosynthetic rate and other related index (G_s: stomatal conductance, C_i: intercellular CO₂ concentration) significantly increased with shading degree increasing. Biomass decreased with the decreasing of irradiance. Plant root/shoot ratio decreased in 50% shading treatment and increased again in 75% and 90% shading treatments. These results suggested that the requirement of E. spectabilise to light was higher and growth was better under 50% shading. The growth of this species was significantly inhibited under more than 75% shading, and some plants even could not survive under 90% shading.

Key words: Eragrostis spectabilis, Shading, Growth

摘要： 丽色画眉(Eragrostis spectabilis)是我国引种栽培的一种新型观赏草,为探讨其对光的生态适应性及生长最适遮荫度,设置4种光照强度处理连续遮荫2年(遮荫度0%、遮荫度50%、遮荫度75%、遮荫度90%),观察测定其生长指标、种子产量、光合作用相关参数以及生物量。结果表明:随着遮荫度的增加,株高和冠幅基本呈上升趋势,90%遮荫度处理下株高从第1个生长季4个处理中最高,转而降至第2个生长季最低;分蘖数和种子产量呈显著下降趋势;叶绿素含量、叶面积、净光合速率及气孔导度、胞间CO₂浓度呈上升趋势,除胞间CO₂浓度外均显著升高;生物量随遮荫度增加显著下降,根冠比则呈先降后升趋势,在50%遮荫度下降至最低,在75%和90%遮荫度下转而连续升高。这说明丽色画眉喜全光照,在遮荫度50%及以下时生长较好;重度遮荫(75%遮荫度及以上)不能够正常生长,个别植株在遮荫90%下甚至不能存活。