模拟酸雨和铝调控对茶叶主要化学品质与铝积累的影响

Effects of Simulated Acid Rain and Al Regulation on Tea Quality and Its Al Accumulation

摘要:

为研究模拟酸雨和铝(Al)对茶叶主要化学品质与Al积累的影响及其交互作用, 采用3个酸度水平(pH 3.0、4.0、5.0)和4种Al浓度水平(0、10、20、30 mg L-1)，用溶液培养法研究茶叶的主要化学指标和Al含量的异同。结果表明，在模拟酸雨下，茶叶的茶多酚和咖啡碱含量随酸度增加先增加后下降，氨基酸、儿茶素和可溶性糖含量则下降，黄酮含量无显著差异。随Al浓度的增加，茶叶茶多酚、咖啡碱、氨基酸、儿茶素、黄酮和可溶性糖含量均先增加后下降。模拟酸雨和Al浓度对茶叶茶多酚、儿茶素和黄酮含量具有显著交互作用，对咖啡碱、氨基酸和可溶性糖含量没有明显交互作用，高酸高Al显著降低儿茶素含量(P<0.05)。适中Al浓度(10~20 mg L-1)促进茶叶的Al积累，而对根、茎和老叶Al积累无明显影响。低浓度Al条件下，酸雨促进茶叶Al的积累，而高酸高Al抑制茶叶Al的积累。综合来看，适中的酸度(pH 4.0左右)和适量的Al浓度有利于提高和稳定茶叶的化学品质。

Abstract:

The influences of simulated acid rain and aluminum (Al) addition on main chemical quality and aluminum accumulation in tea leaves were investigated, which grown in acid deposition regions of red soil in southern China. The tea plants were treated with three pH levels (3.0, 4.0, 5.0) of acid rain and four levels of Al addition (0, 10, 20, 30 mg L-1), respectively. The results showed that the contents of tea polyphenols and caffeine was the highest in tea leaves treated with pH 4.0 acid rain, and the contents of amino acid, catechin and soluble sugar decreased with increasing acidity, while the flavonoid content showed no significant difference among three levels of pH solutions (P<0.05). With the increasing Al concentrations in solution, the contents of tea polyphenols, caffeine, amino acid, catechin, flavonoid and soluble sugar in tea leaves increased first and decreased later. Simulated acid rain and Al addition had significant interactive effects on polyphenols, catechin and flavones, while no interactions on caffeine, soluble sugar and amino acid were found. The catechin content in tea leaves was inhibited by the highest pH (5.0) and Al concentration (30 mg L-1) in solution. The Al accumulation in tea leaves was the highest in the treatment of middle Al concentration in solution (20 mg L-1), while the Al accumulation in roots, shoots and old leaves were not significantly different among three treatments of Al concentration. The Al accumulation in tea leaves increased with decreasing pH solution under lower Al concentration (10 mg L-1), while the Al content in tea leaves was the lowest under the lowest pH (3.0) and the highest Al concentration (30 mg L-1) in solution among the twelve treatments. Therefore, it was recommend that the moderate acidity (pH close to 4.0) and Al content (10~20 mg L-1) in solution was advantaged to improve tea quality.