Abstract:

Effect of aluminum stress on longan (Dimocarpus longana) seedlings was studied. The results showed that aluminum stress induced the change of root exudation content of longan. The membrane permeability and leakage of longan root increased. Compared with control,the concentrations of K⁺,Ca²⁺ ,Mg²⁺ ,soluble sugar,reduced sugars,sucrose,citric acid,malic acid,and oxalic acid,and electricity conductance in the root exudation increased by 13.7%～94.9%,26.9%～ 2 088.5% ,89.5%～871.1%,25.9%～855.6%,27.8%～847.9%,29.2%～921.9%,21.4%～200.0%,14.3%～142.9%,4.9%～97.6%,14.6%～109.9%,respectively. The quantity and kind of amino acid increased at the low concentration of aluminum (≤0.185 mmol·L^-1 for the quantity,≤0.074 mmol·L^-1 for the kind). However,the quantity and kind of amino acid decreased when the concentration of aluminum increased further.

Key words: Longan (Dimocarpus longana), aluminum stress, root exudation