贵州福鼎大白茶低温冻害指标研究

Freezing Damage Indexes of Fortin White Tea in Guizhou Province

为贵州茶叶生产的精准农业气象服务提供科学依据,以贵州茶叶主栽品种福鼎大白茶为研究对象,以植物膜脂过氧化产物丙二醛(MDA)和相对电导率(R)为考察指标,研究低温冻害胁迫环境下贵州福鼎大白茶的生理特性变化,并通过Logistic函数拟合确定低温半致死温度。结果表明:低温胁迫程度不同,福鼎大白茶生理响应特征不同。MDA含量随处理温度的下降呈先升高后下降的趋势,随着胁迫时间的延长总体呈升高的趋势,低温为0℃持续3d时MDA含量达到最大,为2.38μmol/L。相对电导率随低温胁迫程度的加深(不论是温度降低还是胁迫时间延长),均呈上升趋势,但上升的趋势不均匀,其中0℃的低温对相对电导率的影响小,而-1℃和-2℃的低温影响较大。贵州福鼎大白茶低温半致死温度与低温胁迫持续天数正相关,当低温胁迫天数为1d时,低温半致死温度为-3.1℃,而当低温胁迫天数为2d时,低温半致死温度为-3.0℃。因此,茶叶的低温冻害指标应根据当地倒春寒低温冻害天气发生发展过程来确定。

In order to provide scientific basis for precision agricultural meteorological service of tea production,in the paper,Fortin White Tea as major tea cultivar in Guizhou was researched,and the examining indexes were plant membrane lipid peroxidation products malondialdehyde(MDA)and relative conductivity(R),the physiological characteristics and semi-lethal temperature of Fortin White Tea in the low temperature stress environment were studied.The semi-lethal temperature was determined by Logistic function.Results:The physiological response characteristics of Fortin White Tea were different under different low temperature stress.MDA content first increased and then decreased with the decrease of treatment temperature,increasing with the extension of stress time.MDA content reached the maximum(2.38μmol/L)at a low temperature of 0℃and sustaining 3 days.The relative conductivity increased with the deepening of low temperature stress(no matter the temperature decreased or the stress time prolonged),while the trend of increase was uneven.The low temperature of 0℃had little effect on the relative conductivity,while the low temperature of-1℃and-2℃had a greater effect.Low-temperature semi-lethal temperature was positively correlated with the duration of low-temperature stress days.When the low-temperature stress lasted for 1 d,the low-temperature semi-lethal temperature was-3.1℃,while the low-temperature stress lasted for 2 d,the low-temperature semi-lethal temperature was-3.0℃.Therefore,the low-temperature freezing injury index of tea should be determined according to the development process of the late spring coldness.