主要气象因子对'黄金芽'茶树叶片日灼伤害的影响

摘要

'Huangjinya', one of light sensitive tea germplasm resources, was bred from natural yellow mutant single plant in Deshi tea plantation, Yuyao City, Zhejiang Province, in 1998.It is prone to cause physical disorder and leaf sunburn when the light intensity is more than 60 klx.The occurrence and symptoms of leaf sunburn of 3-year-old tea cultivar 'Huangjinya' (HJY) were investigated in Taian area from April to July in 2016.At the same time, the leaf temperature and three main meteorological factors including light intensity, air temperature and humidity were also measured.The difference between leaf temperature and air temperature (ΔTL-A) was calculated, and the effects of main meteorological factors on leaf temperature and ΔTL-A were explored to analyze the occurrence conditions of leaf sunburn.The results were as follows.(1) The symptoms of leaf sunburn could be generally divided into three main types: white, red and necrotic, and the degree of burn injury aggravated in turn.(2) Tea cultivar 'HJY' began to show symptoms of leaf sunburn in mid May, and this phenomenon was particularly obvious from late May to June in Taian area.(3) Blaze light intensity and high leaf temperature were the two necessary conditions for causing leaf sunburn of 'HJY'.The phenomenon of leaf sunburn appeared when the daily maximum light intensity exceeded 100 klx and the daily maximum leaf temperature exceeded 38~40℃.The threshold temperature of leaf sunburn was 38℃ when the leaf temperature varied greatly throughout the day.However, it could be increased to 40℃ if the leaf temperature change was small and the leaves were exercised in high temperature.(4) The leaf temperature and ΔTL-A were significantly affected by light intensity, air temperature and air humidity, but their relevance was various in different periods.According to the above results, some technology measures such as shading, intercropping and sprinkler which could dim light, cool temperature and increase air humidity were put forward, and they could prevent 'HJY' from leaf sunburn effectively in the sensitive period.%'黄金芽'是1998年由浙江余姚市德氏茶场发现的自然黄化变异单株培育而成的光照敏感型茶树种质资源,光照强度超过60 klx时易出现生理障碍,造成叶片日灼.2016年4-7月份调查了泰安茶区三年生'黄金芽'叶片日灼发生情况及其症状,测定了叶温以及同期光强、气温和湿度三个主要气象因子,计算了叶温与气温的差值ΔT叶-气,探究了主要气象因子对叶温以及ΔT叶-气的影响,分析了叶片发生日灼的条件.结果表明:(1)'黄金芽'叶片日灼症状主要分为白化型、红变型和坏死型三种,其日灼伤害程度依次加重;(2) 泰安茶区栽种的'黄金芽'5月中旬开始出现日灼现象,5月下旬至6月发生较为严重;(3)高光强和叶片高温是引起'黄金芽'叶片日灼的两个必要条件.在日最大光强达100 klx以上,日最高叶温38~40℃以上时可出现日灼现象.当叶温日变幅大,发生日灼的叶温阈值较低(38℃);叶温日变幅小且经过高温锻炼后,发生日灼的叶温阈值可提高至40℃;(4) 叶温以及ΔT叶-气受光强、气温和空气湿度的显著影响,但不同时期相关程度不同.根据上述结果,提出了通过在'黄金芽'日灼易发时期采取覆盖遮阳网、间作以及喷灌等减光、降温和增湿技术措施,可以有效预防'黄金芽'叶片日灼的发生.