三类云南普洱茶树的地基光谱反射特征及其差异分析

Analysis of Ground-based Spectral Reflection Characteristics and Differences of Three Types of Yunnan Puer Tea

茶树类型和产地来源影响普洱茶品质,而茶树类型和产地不同,其冠层光谱也存在特征性差异。因此,利用这一特征差异,可明确普洱茶鲜叶来源,对保证普洱茶品质具有重要意义。本研究以云南景东、景谷、澜沧、宁洱4个典型普洱茶山的古树茶、大树茶、台地茶为研究对象,用地基光谱测定仪测定其野外冠层叶片光谱反射率,分析它们之间的光谱反射特征和差异性,揭示云南普洱茶树的地基光谱反射规律。结果显示:(1)不同普洱茶树冠层叶片光谱反射率存在差异,在近红外波段上,古树茶与台地茶光谱反射率差异显著可区分,古树茶与大树茶两者光谱反射相近似,古树茶平均反射率高于大树茶;(2)不同类型冠层叶片光谱反射率在近红外波段上表现为古树茶>大树茶>台地茶;同类型茶树冠层叶光谱反射率表现为澜沧>景东>景谷,与3地年平均温度呈正相关关系,与海拔呈负相关关系;(3)754、801、891 nm波长可作为选择区分3种类型普洱茶的理想波长,其中801 nm可作为区分不同地区古树茶的特征波长。

The type and producing area of tea plants affect the quality of Puer tea,and there are characteristic differences in canopy spectrum of tea plants of different types and producing area.It is great significance to make clear the source of fresh leaves and guarantee the quality of Puer tea by using this characteristic difference.In this study,the ancient tree tea,large tree tea and platform tea from four typical Puer tea mountains of Jingdong,Jinggu,Lancang and Ning'er in Yunnan Province were collected to measure spectral reflectance of their canopy leaves.The characteristics and differences of spectral reflectance were also analyzed and finally the ground-based spectral reflectance of Puer tea trees in Yunnan was revealed.The results showed that:(1)there were differences in spectral reflectance of canopy leaves of different Puer teas.In the near-infrared band,the differences in spectral reflectance of ancient tree tea and platform tea were significant.The spectral reflectance of ancient tree tea was similar to that of large tree tea.Meanwhile,the average reflectance of ancient tree tea was higher than that of large tree tea.(2)The spectral reflectance of different types of canopy leaves was shown as ancient tree tea>large tree tea>platform tea in the near infrared band.The spectral reflectance of canopy leaves of the same type of tea was Lancang>Jingdong>Jinggu,which has a positive correlation with the annual average temperature of the three places and a negative correlation with altitude.(3)Wavelength 754 nm,801 nm and 891 nm were selected as the best wavelength points to distinguish three types of Puer tea,and 801 nm could be used as a characteristic wavelength point to distinguish ancient tree tea from different regions.This study provided technical support for the source of fresh leaves of Puer tea and the identification of tea species.