基于色差仪的茶树叶色量化研究OA北大核心CSTPCD

[Objectives]This study was conducted to explore the relationship and distribution of leaf color among tea plant populations,and also to determine the best colorimeter parameter for a quantitative description of tea plant leaf color,so as to provide a theoretical basis for leaf color description and classification.[Methods]Taking 120 tea varieties(or lines)as the research object,the lightness(L*),redness(a*),yellowness(b*),chroma(C*),total color value(E*),hue angle(h)and saturation(S*)of tea plant leaves were measured with a colorimeter and the statistical analysis was conducted,including normality test,non-parametric multiple comparisons,principal component analysis,cluster analysis,and correlation analysis.[Results]From yellow,green to purple green,L*,b*,C*,E*,and S* values of leaves decreased gradually and a*value increased firstly then decreased.The h value was the biggest in green tea plants,and there was no significant difference in the h value between purple green and yellow tea plants.Most of the seven parameters were normal in green tea plants but abnormal in yellow and purple green tea plants,which suggested that the selection pressure of yellow and purple green tea plants was bigger than that of green tea plants.The result of the principal components analysis indicated that there were differences in lightness and saturation between groups of tea plants of different colors,and differences in redness and greenness within groups.The result of multiple comparisons showed that the S* value had the best discrimination of leaf color of diverse tea varieties(lines)and the a*value the worst.When the euclidean distance equaled 8.78,120 tea varieties(lines)were clustered into three categories,which was consistent with the classification that was divided by visual observation.L*,b*,C*,E* and S* values had a strong correlation with the chlorophyll content,and all the correlation coefficients were bigger than 0.70;a* value had a strong correlation with the anthocyanin content,and the correlation coefficients was 0.76.[Conclusions]The S*value had the best discrimination of leaf color of diverse tea varieties(lines)and had a relatively strong correlation with chlorophyll content and anthocyanin content,then it could reflect the content of chlorophyll and anthocyanin in tea plants to a certain extent,so the saturation S*could be chosen as the best colorimeter parameter for accurately accessing the leaf color of tea plants.