不同遮荫水平对茶树光合环境及茶叶品质的影响

试验研究了夏秋季80%、61%、37%遮光率遮阳网覆盖处理对茶园生态环境、茶树光合作用特性和茶叶内含成分的影响。结果表明:与露地对照茶园相比,3种遮光率遮荫处理茶园夏秋季气温、叶面温度、地面温度和土壤温度均明显降低;茶园土壤水分含量、茶园空气湿度明显提高。遮荫改善了茶园生态环境,且遮光率越高,效果越明显。与对照茶园比较,80%、61%、37%遮光率遮阳网覆盖处理日平均净光合速率增加了365%、283%和68%;茶叶新梢的叶绿素a含量增加了57.5%、29.3%和15.9%,叶绿素总量增加了52.2%、29.2%和14.3%;茶叶氨基酸含量增加了68.6%、33.5%和2.16%;茶叶茶多酚含量降低了15.3%、12.5%和5.4%。80%遮光率处理1芽2叶新梢制作的茶叶酚氨比达到名优绿茶标准,61%遮光率和37%遮光率处理的茶叶酚氨比也均达到高档绿茶标准,茶叶品质明显优于对照茶园。

Tea plantation environment and quality under different degrees of shading

Environmental factors,photosynthesis and evaporation characteristics,and tea ingredients were studied at a selected tea field with 80%,61% and 37% shadings in the summer and autumn.Results show that shading operation remarkably reduces air temperature,leaf surface temperature,ground temperature and soil temperature,and increases soil water contents and air humidity.Shading effects on tea garden environment are enhanced with increase in shading degree.In comparison with unshaded tea garden,net photosynthetic rates of tea under 80%,61%,37% shadings increase by 365%,283%,68% respectively;chlorophyll-a contents in the tea leaves increase by 57.5%,29.3% and 15.9%,and total chlorophyll contents increase by 52.2%,29.2% and 14.3% respectively;amino-acid(AA) contents increase by 68.6%,33.5% and 2.16% respectively;and tea polyphenol(TP) contents drop by 15.3%,12.5% and 5.4% respectively.TP/AA ratio in processed tea from two-leaf and one-bud-shoot under 80% shading meets high-grade green-tea standards,and that at 61% and 37% shadings reaches fine-grade green-tea standards;much better than those of unshaded tea gardens.