Relationship of SPAD, chlorophyll and LMA in Osmanthusfragrans leaves | 桂花叶片SPAD、叶绿素含量和比叶重特征

Chinese. 对金桂（D.fragransvar.thunbergii）和四季桂（O.fragransvar.semperflorens）叶片的比叶重、叶绿素含量、叶片SPAD值以及养分含量进行了研究，探讨了SPAD值与叶绿素含量的相关性。结果表明，金桂叶片叶绿素a／b值低于四季桂，其他指标均高于四季桂；不同植株四季桂叶片的各指标含量均无显著差异（P0.05），而金桂叶片的叶绿素a、叶绿素b、叶绿素总量（a＋b）、类胡萝卜素含量在不同植株间差异显著（P0．05）；四季桂（16．32cm-2）的叶面积要小于金桂（35．37cm2），而四季桂的比叶重却略大于金桂，比叶重均值分别为18.53和16.62mg/cm-2；四季桂和金桂叶片均偏酸性；四季桂叶片磷含量、镁含量均高于金桂，钙含量、钾含量分别小于金桂；叶片叶绿素总含量与SPAD值呈显著相关。在城市热岛现象突出的情况下，金桂的叶面积大，适应强光能力强，更适合在城市绿化中推广使用。

English. Leaf mass per unit area（LMA）, chlorophyll content, leaf SPAD value and the nutrient content of Osmamthusfragrans var.thunbergii and Osmanthusfragrans var. semperflorens leaves were studied, and the correlation of SPAD and chlorophyll content was discussed. The results were as follows. The chlorophyll a / b in O. fragrans var. thunbergii was lower than that in O. fragrans var. semperflorens leaves, but other indicators were higher; each index in leaves of O. fragrans var. semperflorens plants was not significantly different （P0.05）, while chlorophyll a, chlorophyll b, total chlorophyll （a ＋ b） and carotenoid content in leaves of different O. fi＇agrans var. thunbergii plants were significantly different （P〈0.05）; the leaf area of O. fragrans var. semperflorens（16.32 cm2） is less than O. fragrans var. thunbergii （35.37cm2）, but the LMA was on the contrary. The leaves are partial to the acidity with pH 5- pH 6; the P and Mg contents in O. fragrans var. semperflorens leaves were higher than those in O. fragrans var. thunbergii leaves, while the calcium and potassium contents were on the contrary. The total chlorophyll content and SPAD values were significantly correlated. At present, the phenomenon of urban heat island was prominent, and O. fragrans var. thunbergii has big leaf areas and strong adaptation to light, which is more suitable to popularize in urban greening.