云南省千家寨古茶树生态适应机理研究

Yunnan is the first place where the tea is discovered and cultivated, and is well known for the high abundance and wide distribution of wild tea plants. The wild tea plant community, which located in Qianjiazhai, Ailao Mountain Natural Reserve in Zhenyuan county of Puer city has important scientific reasearch interest, due to the largest area, the most intact preservation and the 2,700-year-old tea tree being called “living fossil”. In this project, the most representative ancient wild tea plant populations at different altitude of Qianjiazhai in Yunnan province are selected as materials, the genetic relationship and molecular evolution in the natural populations of tea plant are to explore genetic diversity and genetic relationship will be analyzed by EST-SSR molecular markers; moreover, combined with the different habitat and climate environment at different altitude, the ecological adaptability and tea quality characteristics of the ancient tea plants will be studied to explore the relationship between plants funcitonal trait (growth, survival, phsyiological metabalisim) and the climatic and edaphic factors in natural populations of the ancient tea plant. The results of this study not only can lay the foundation for the development, protection and utilization of ancient tea plant and breeding of new variety tea cultivation, but also has important practical significance to ensure the sustained, healthy and stable development of Yunnan tea industry.

云南是世界上最早发现、利用和栽培茶树的地方，也是野生茶树和现存茶树最多、最集中的地方，而位于普洱市镇沅县哀牢山自然保护区的千家寨野生古茶树群落因其面积最大、保存程度最完整且存有两千多年的“活化石”茶王树，具有重要科研价值。本项目选取云南省千家寨野生古茶树不同海拔群体为研究对象，拟利用EST-SSR分子标记对其进行遗传多样性和亲缘关系分析，探讨其种质资源的遗传关系与分子进化；并结合不同海拔生境及气候环境研究古茶树的生态适应性及茶叶品质特性差异，探讨古茶树天然群体的生长、生存、生理代谢等与土壤及气候因子的关系，其研究结果不仅可为古茶树的保护开发利用及新品种的选育栽培奠定基础，对确保云南茶产业持续、健康和稳定发展亦具有重要的现实意义。

本项目选取云南省千家寨自然保护区4个不同海拔群体（A2050m、A2200m、A2350m、A2500m）野生古茶树为研究对象，对其遗传多样性、叶片解剖结构、生理生态特性、代谢组学及土壤微生态环境进行了研究，并就野生型茶树与保护区外的栽培型茶树进行了对比研究；主要研究结果如下：1）随海拔的增加，野生古茶树群体遗传多样性下降，居群间的遗传分化水平较低，而居群内部变异是其主要的变异来源；种群间的基因流（Nm）为8.52，表明高的基因流也可能是导致千家寨野生古茶树居群间遗传多样性高的主要因素。2）千家寨野生古茶树根际土壤养分储备充足，pH值（4.56~4.64）在适宜茶树生长的范围，其大多数土壤养分含量随海拔的增加而增加；千家寨野生古茶树根际土壤受磷限制和碳限制相对于氮限制程度更高，在不同海拔中受碳氮磷限制的程度有差异；海拔梯度上的细菌群落与多种土壤因子相关，根际土壤铵态氮（NH4+-N）含量是影响细菌群落多样性和沿海拔梯度分布的关键因素。3）千家寨4个海拔野生古茶树群体叶片解剖结构、化学计量比、代谢物质成份等均差异显著。中间海拔更有利于野生古茶树的光合碳同化，生长代谢较为旺盛，随海拔的升高，茶树叶片解剖结构和元素计量特征的变化均有利于提高其保水能力和抗旱抗寒能力；代谢组分析表明低海拔下的茶树合成黄酮及黄酮醇类物质的能力较强，而高海拔下的茶树合成酚酸类物质较多，可能与其抗逆性相关。4）相比于台地茶，野生型古茶树与栽培型古茶树对环境具有较强的适应能力，叶肉细胞表皮和角质层较厚，内含物更丰富，更有利于成品茶条索的完整度和耐泡度，更适合制作高端普洱，且野生型和栽培型无显著差异；栽培型台地茶叶片生长快而薄，更有助于高产、旺产，后期适宜制作中高档或大宗茶类。本项目研究结果不仅为野生古茶树的保护与利用提供了理论指导，也对确保云南产茶业的可持续健康发展具有重要的现实意义。在本项目资助下，已发表研究论文4篇，培养研究生4名。