[Effects of magnesium deficiency on senescence of Dimocarpus longana leaves].

180 days old Dimocarpus longana seedlings were grown in nutrition solution with three magnesium concentrations as 4 mmol.L-1 Mg2+ (sufficient supply), 0.4 mmol.L-1 Mg2+ (deficient supply), and Mg-free (without supply). Leaves were sampled 120 and 150 days later after treatment. With an increase in severity of Mg-deficient, the chlorophyll content, PS II activities, photosynthetic rate, protein, nucleic acid (DNA, RNA), and ZRs contents declined progressively. Whereas the content of H2O2, the rate of O2-. generation as well as the content of malondialdehyde (MDA) increased. The results suggested that magnesium deficiency had significant effect on the senescence of Dimocarpus longana leaves.