湖北青砖茶叶片发酵前后形态变化比较

Comparative Study on Leaf Tissue Morphologic Changes of Green Brick Tea on Hubei Province Before and After Fermentation

为了解湖北青砖茶发酵过程的变化实质,试验分析了湖北青砖茶在发酵前后叶片组织结构的变化情况,分别取发酵前后10片茶叶叶片,切片染色处理后于光镜下观察,统计叶片纤维组分与细胞胶团质组分的面积大小,分析面积变化情况。同时做叶片的透射电镜观察。结果表明,与发酵前的茶叶相比,发酵后的叶片组织较为疏松,细胞室变大,由纤维素构成的细胞壁结构明显变薄,甚至出现断裂;叶片内可见菌体明显的断面。图像分析显示,叶片组织的纤维成分减少显著,而黄色的细胞胶团质成分的含量相对增加。电镜观察发现,胞壁室内位于胶团质和细胞壁之间的空隙内有多量菌体存在。所以湖北青砖茶的发酵过程是以微生物为主导、对茶叶进行生物转化的过程,这种转化主要消耗叶片组织中的纤维素成分。

To understand the change of fermentation process of green brick tea on Hubei province, we conducted this study to show the changes in the contents of structure components of tea leaves before and after fermentation. Choosed ten tea leaves before and after fermentation. The tea leaves section were made using paraffin microtomy, PAS staining, and observed under light microscopy. Through image analysis for the tea leaves, we compared the changes on the areas of the cellulose and colloid in cell before and after pile-fermentation. At the same time, the tea leaves were observed under transmission electron microscope. The results showed that the pile-fermentation process caused the tea leaves tissue to become loose, and made the cell space greaten. Besides, the cell wall of tea leaves is obviously thinning, and even breaking which composed of cellulose.Image analysis showed that the leaf fiber composition reduced significantly, with a corresponding increase of yellow colloid in cell. Under observation of transmission electron microscope, there are large amounts of fungi located in the space between the colloid and the cell wall of the tea leaves after pile-fermentation. The fermentation of green brick tea is the process of microbial biotransformation of tea, which dominated by microbe and consumed the cellulose components of tea leaves.