© 2015, Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków. Response of tea plants (Camellia sinensis (L.) O. Kontze) to Al (300 µM AlCl3 for 14 weeks) was studied in combination with deficient (−B) or adequate B supply (+B) in hydroponics. Aluminum improved plant growth under B deficiency. This positive Al effect in (−B) plants was related to an Al-induced increase of B contents in the root cell walls (CW). Moreover, in (−B) plants more Al was partitioned into CW-bound fractions in both leaves and roots than in (+B) plants; an indication that B deficiency reduced the mobility of Al in the tea plants. In general, the highest activities of phenylalanine ammonia lyase, polyphenol oxidase, and soluble and CW-bound fractions of peroxidases were observed in (+Al/−B) plants. In (−B) plants Al supply caused a reduction of CW-bound phenolic acids and lignin, while the concentrations of soluble phenolics increased in the leaves. In the roots, however, Al treatment of B-deficient plants caused a significant increase of CW-bound phenolic acids, but not of lignin. Our results suggest that increased B partitioning into CW and reduction of lignification were important causes for Al-mediated amelioration of growth in B-deficient plants. In addition, the observation that in (+Al/−B) roots CW binding of both Al and phenolic acids was enhanced indicates that in the B-deficient roots Al was mainly bound to the CW phenolic acids; this, in turn, reduced their availability for enzymatic reactions and lignin synthesis.
- Cell wall