Impacts of Aluminum on Root Cell Membrane Permeability and Organic Acids in Root Exudates of Tea Plant

The impacts of aluminum(Al) concentration on root cell membrane permeability and components of organic acids in root exudates of tea plant(Camellia.sinensis L.) were investigated by hydroponics.Results showed that 20 mg/L of low Al concentration could enhance the cell membrane stability of tea root,and the membrane permeability was significantly declined with deficiency Al(0 mg/L,CK) and high Al(100 mg/L) treatments.The total organic acids firstly decreased and then increased with the increase of Al concentrations.About 85%~93% of the total organic acids in root exudates of tea plant were oxalic acid,malic acid and citric acid.Compared with CK,the oxalic acid secretion remarkably reduced 84.7% and 34.3% under the low and high Al concentration treatments.Compared with CK,the malic acid of root exudates increased by 121.1% in low Al concentration,and decreased by 40.9% in high Al concentration.There wasn't significant influence on citric acid,containing about 3.5~4.5 mg/g.This result can provide critical data for elucidating tolerance mechanisms of Al stress on tea root.