Short communication Localization of aluminium in tea leaves

More than 30,000 ppm of aluminium (Al) was found accumulated in old tea leaves. The localization of Al in epidermal cells was detected by light microscopic observation and electron microprobe X-ray analysis. A distinct thickening of epidermal cell wall was seen in old leaves. The addition of AICI3 to the cultural solution promoted the growth of tea seedlings. Aluminium (Al) is one of the major soil constituents. Solubilized Al3+ in acid soil can be absorbed via roots and thereby affect plant growth (5). The Al content in plants growing in neutral soil are usually not high. Exceptional plants containing large amounts of Al are known as Al-accumulating plants (10,12). They often grow in acid soil. Tea (Camellia sinensis) is a well-known Al-accumulating plant, whose old leaves often contain more than 10,000 ppm of Al. However, the localization and physiological role of Al in plants has not been studied except for investigations of the toxicity of Al given to plants or plant tissues artificially (1, 2). It has been reported that Al was localized in nuclei and cell walls of various plant roots cultured in Al3+ solution (1, 3, 7). Several hypotheses were proposed re