春茶采摘末期遮荫对其生长和品质的影响

Effects of Shading Cultivation on Growth and Quality of Spring Tea during Final Harvesting Period

为延长春茶采摘期,提高其产量,进行了遮阳网遮荫栽培试验研究。根据不同遮光率和不同遮荫高度,在茶园中设置4个处理:60%遮光率+2.0 m遮荫高度(T1)、40%遮光率+2.0 m遮荫高度(T2)、40%遮光率+2.5 m遮荫高度(T3)和无遮荫的对照处理(CK);试验全程分为前、中、后期。试验研究以上各处理遮阳网内外温、湿度环境的差异,茶树新稍、叶片生长状况和茶芽叶品质指标。结果表明:遮荫后,茶树冠层处的日最高气温显著降低,遮光率越高降幅越大,最大降幅为3.9℃;08:00—17:00的最低相对湿度均增大,遮光率越高增幅越大,最大增幅为9.01%;新稍长度、粗度均增加,以T1处理的增幅最大,分别为22.3%和13.5%;新稍叶片的叶绿素相对含量和芽叶含水率,随着遮光率增大而增高;与CK处理相比,T1处理的新稍叶片日平均净光合速率变大,而T2和T3显著变小;T3处理增加了茶叶水浸出物、茶多酚和酚氨比,降低了氨基酸含量,导致茶汤浓厚、苦涩味加重;而T1处理在试验前期增加了咖啡碱含量,降低了水浸出物含量和酚氨比。综上所述,在春茶采摘末期采用60%遮光率的遮阳网进行遮荫栽培,对于保持春茶品质、延长采摘期具有重要的生产指导意义。

In order to extend the plucking period of spring tea and improve its yield,the shading cultivation experiment was carried out. Three treatments with different shading rates and shading heights were applied as 60% shading rate with shading height of 2. 0 m（T1）,40% shading rate with shading height of 2. 0 m（T2）,40% shading rate with shading height of 2. 5 m（T3） and none-shading（CK）. The experiment period was divided into early,middle and late stages from final harvesting period. The differences of temperature,relative humidity,growth status and tea quality among all treatments were analyzed. Compared with CK,the results showed that after shading,maximum daily air temperature around canopy was decreased significantly with the maximum temperature drop of 3. 85℃ and average minimum relative humidity around canopy was increased with the maximum increase of 9. 01% from08： 00 to 17： 00; the new twig length and the stem thickness of T1 were increased by 22. 3% and13. 5%,respectively; as shading rate was increased,relative chlorophyll content（SPAD） and water content of leaves and buds were increased; the average photosynthetic rate of leaves of T1 was increased,while those of T2 and T3 were decreased; as for T3,water extract,polyphenols and the ratio of polyphenols to amino acid were increased,but amino acid was decreased,leading to the tea tasted thicker and bitter; as for T1,its caffeine was increased,while water extract and the ratio of polyphenols to amino acid were decreased significantly during the early stage. Therefore,shading cultivation with shading rate of 60% was of significance to maintain the quality of spring tea,extend the plucking period and increase yield during final harvesting period.