覆盖遮荫对乌龙茶产量、品质的影响

夏暑季乌龙茶园覆盖遮荫的生态生理生化效应及其对茶树生长、产量和品质的影响结果表明:遮荫后,1)树冠层的白昼平均温度、日极端最高温度、温度日较差和相对湿度日较差显著下降,白昼平均相对湿度和日极端最低相对湿度显著增加。2)夏、暑梢1芽3叶含水率分别增加了4.57%~6.47%和2.24%~2.78%。3)夏、暑梢叶绿素总量及其a、b含量分别提高了41.70%~48.92%和52.38%~91.06%、38.96%~47.25%和 50.94%~72.52%、43.83%~54.58%和67.98%~155.81%;叶绿素a、b比值下降了0.1042~0.1868和1.10~3.54。4)叶片及其表皮层、角质层、栅栏组织和海绵组织的厚度变薄,叶面积增大,栅/海比值变小。5)茶多酚、粗纤维和咖啡碱的含量明显降低,氨基酸含量明显提高,儿茶素品质组份得以优化。6)适度遮荫,可以提高夏暑茶的产量和品质。

Effects on the Yield and Quality of Oolong Tea by Covering with Shading Net

The effects of shading on ecology, physiology and biochemistry of Oolong tea by covering with black shading net in relative tea field in summer season were investigated by the authors. Results showed that in compared with control, the average temperature of daytime, maximum temperature, temperature difference and the relative humidity difference in plucking table of tea plant had been decreased remarkably, while the relative humidity of daytime and the daily minimum relative humidity in plucking table of tea plant in the shading treatment were remarkably increased. In compared with control, moisture content of shoots with one bud and three-leaves in the treatment of shading in summer and hot summer day was increased by 4.57%~6.47% and 2.24%~2.78% respectively. The content of total chlorophyll in leaves of the tea shoot in summer and hot summer day were respectively increased by 41.70%~48.92%and 52.38%~91.06%over the control. Similarly, chlorophyll a by 38.96%~47.25% and 50.94%~72.52%,while chlorophyll b by 43.83%~54.58%and 67.98%~155.81% were increased. Whereas the ratio of chlorophyll a and b was decreased by 0.1042~0.1868 and 1.10~3.54 respectively. After shading, the leaf epidermis, cuticle, palisade tissue, spongy tissue was thinned, while the lamina area was decreased, and the ratio of palisade tissue to spongy tissue was decreased. After shading, the contents of tea polyphenols, crude cellulose and caffeine in fresh leaves are all obviously reduced, while the contents of amino acid in fresh leaves are obviously increased. It was regarded that moderate shading could improve the quality and the yield of Oolong tea.