Abstract: Leaf color is one of the most important ornamental features of ornamental grasses. In this paper,Pennisetum purpureum ‘Red’,Pennisetum setaceum ‘Rubrum’ and Imperata cylindrica with colored leaves in winter were as objects to analyze their leaf color characteristics and the relationship between leaf color and chlorophyll using the Lab model so that it could provide a reference for the key indicators of ornamental grass breeding and color quantification. The results showed that the L value of Pennisetum purpureum ‘Red’ was the lowest and the a value was stable. The a value of Pennisetum setaceum ‘Rubrum’ was the biggest,and the L and b values of Imperata cylindrica were the biggest. On the same leaf,the a value of the base of Pennisetum purpureum ‘Red’ was the biggest and had significantly different from the middle and the top. The L value of the top of Pennisetum setaceum ‘Rubrum’ was the biggest and had significantly different with the other two parts. The L and b value of the base of Imperata cylindrica were bigger. In the same plant,the a value of the top of Pennisetum purpureum ‘Red’ was the biggest and the lower b value was higher. The a value of the top and bottom of Pennisetum setaceum ‘Rubrum’ was bigger. The smallest a value of Imperata cylindrica was the highest. The leaf color parameter had significant or extremely significant negative correlation with chlorophyll content. According to the analysis,the leaf color of each ornamental grass was different,and chlorophyll was one of the main factors affecting the color of the ornamental grass. The leaf color characteristics should be fully considered when plants are planted.

Key words: Pennisetum purpureum ‘Red’, Pennisetum setaceum ‘Rubrum’, Imperata cylindrica, leaf color parameters, Lab model, chlorophyll

摘要： 叶色是观赏草最重要的观赏特性之一，本文以紫叶象草（Pennisetum purpureum ‘Red’）、紫叶狼尾草（Pennisetum setaceum ‘Rubrum’）和白茅（Imperata cylindrica）在冬季为彩叶的三种观赏草为研究对象，基于Lab模型，分析了三种观赏草的叶色特征及叶色与叶绿素之间的关系，为观赏草品种选育的关键指标提供参考依据，也为色彩定量分析提供思路。结果表明：个体间，紫叶象草L值最低且a值变化较平稳，紫叶狼尾草叶色a值最大，白茅L值和b值最大；同一叶片上，紫叶象草叶片基部a值最大且与中部和尖部有显著差异，紫叶狼尾草尖部L值最大且三个部位L值均有显著差异，白茅基部L值和b值较大；同一株观赏草中，紫叶象草的顶端新叶a值最大且越低处叶片b值越大，紫叶狼尾草顶端和底部a值较大，白茅越低处叶色a值越大；叶色参数a与叶绿素含量呈显著或极显著负相关。分析可知，每种观赏草的叶色变化不同，其中叶绿素是影响观赏草叶色红色的主要因素之一，在植物配置时需充分考虑其叶色特征。

关键词: 紫叶象草, 紫叶狼尾草, 白茅, 叶色参数, Lab模型, 叶绿素