College of Horticulture/College of Foreign Languages, Qingdao Agricultural University, Qingdao, China.
Key Laboratory of Tea Plant Biology and Resources Utilization, Tea Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Hangzhou, China.
J Sci Food Agric. 2021 Oct;101(13):5678-5687. doi: 10.1002/jsfa.11222. Epub 2021 Apr 16.
The proper growth and development of tea plants requires moderately acidic soils and relatively low calcium levels, and excessive calcium at high pH can damage tea plant roots. To reveal the effects of calcium on the responses of tea plant to three pH levels (3.5, 5.0 and 6.5), a repeated test of two factors was designed.
Root growth and elemental analysis indicated that excessive calcium improved the growth of tea roots at low pH conditions, whereas it did not harm the growth of tea roots under normal and high pH conditions, especially at pH 6.5. Excessive calcium antagonized the absorption and utilization of magnesium by tea plants. Gas chromatography-mass spectrometry results showed that the addition of Ca resulted in the primary metabolism in roots being more active at a low pH level. By contrast, it had obvious adverse effects on the accumulation of root metabolites with high calcium treatment at normal or high pH. Differential metabolites identified using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry indicated that flavonoids demonstrated the largest number of changes, and their biosynthesis was partially enriched with excessive calcium at low and high pH conditions, whereas it was down-regulated under normal pH conditions. Kaempferol 3-(2'-rhamnosyl-6'-acetylgalactoside) 7-rhamnoside, quercetin 3-(6'-sinapoylsophorotrioside) and delphinidin 3-(3'-p-coumaroylglucoside) showed the greatest increase. The results of gene expression related to root growth and calcium regulation were consistent with root growth and root metabolism.
The overall results demonstrated that high Ca concentrations further aggravate the detrimental effects of high pH to tea roots. However, it is interesting that excessive calcium reduced the harm of a low pH on tea root growth to some extent. © 2021 Society of Chemical Industry.
茶树的正常生长和发育需要适度酸性的土壤和相对较低的钙水平，而高 pH 值下过量的钙会损害茶树根系。为了揭示钙对茶树对三种 pH 值（3.5、5.0 和 6.5）响应的影响，设计了一个两因素重复试验。
根生长和元素分析表明，过量的钙在低 pH 条件下改善了茶树根系的生长，而在正常和高 pH 条件下不会损害茶树根系的生长，尤其是在 pH 6.5 时。过量的钙拮抗了茶树对镁的吸收和利用。气相色谱-质谱联用结果表明，在低 pH 条件下，Ca 的加入使根的初级代谢更加活跃。相比之下，高钙处理对正常或高 pH 下根代谢物的积累有明显的不利影响。利用超高效液相色谱-四极杆飞行时间质谱鉴定的差异代谢物表明，类黄酮的变化最多，其生物合成在低和高 pH 条件下部分富集了过量的钙，而在正常 pH 条件下则下调。山奈酚 3-(2'-鼠李糖基-6'-乙酰半乳糖苷) 7-鼠李糖苷、槲皮素 3-(6'-芥子酰基山柰酚三糖苷)和飞燕草素 3-(3'-对香豆酰基葡萄糖苷)的增加最为显著。与根系生长和钙调节相关的基因表达结果与根系生长和根系代谢一致。
总体结果表明，高浓度的 Ca 进一步加剧了高 pH 对茶树根系的不利影响。然而，有趣的是，过量的钙在一定程度上减轻了低 pH 对茶树根系生长的危害。© 2021 化学工业协会。
