The mechanisms for soil acidification induced by tea plant growth are not well understood. Proton release from tea plant (Camellia sinensis L.) roots induced by aluminium (Al(III)) in solution-culture experiments was examined with an automatic titration system to determine the effect of Al(III) uptake by the plants on soil acidification. Results indicated that the uptake of Al(III) by tea plants led to proton release from their roots and thus an increase in soil acidification. The uptake of Al(III) by tea plants and the amount of protons released from the roots was greater at pH 4.5 than at pH 5.0 and 4.0 and increased with increasing initial Al(III) concentration in the culture solutions. With the same initial pH the amount of protons released from tea plant roots at a constant pH was much higher than that at non-constant pH. The presence of ammonium increased the amount of protons released from tea plant roots. Therefore the uptake of Al by tea plants and subsequent release of protons from their roots may be an important mechanism by which they acidify soils in tea gardens.

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水培条件下Al(III)对茶树根系质子释放的影响

万青，徐仁扣，黎星辉

Soil Research 2012 50(6):482-488

http://dx.doi.org-10.1071-SR12099

    摘要：关于茶树生长而引起土壤酸化的机制尚未研究清楚。利用自动电位滴定系统开展水培条件下铝(Al(III))诱导茶树根系释放质子的实验，从而分析出植物吸收铝后对土壤酸化的影响。结果表明，由于茶树吸收铝而引起质子释放，所以导致土壤酸化。茶树在初始pH4.5条件下吸收铝离子量以及引起的质子释放量要显著高于pH5.0和4.0条件下的，并且质子释放量随着铝初始浓度的增加而增加。相同初始pH时，茶树根系在恒pH条件下的质子释放量显著高于非恒pH条件下的。铵的存在提高其根系的质子释放量。因此，茶树根系吸收铝而引起的质子释放可能是茶树酸化土壤的重要机制。