Chlorophyll and Nutrient Characteristics in Leaves of Three Young Stands

Contents of chlorophyll, N, P, K, Ca and Mg in leaves of young Acacia auriculiformis, Michelia macdurei and Rhodoleia championii stands were studied. Chlorophyll was extracted from the discs for 72 h in the dark using N, N-dimethylformamide. Absorbances at 647 and 664 nm were determined with a Shimadzu UV-/vis spectrophotometer. Concentrations of N, P, K, Ca and Mg were determined by micro-Kjeldahl technique, chloro molybdophosphonic blue colour, and atomic absorption methods, respectively. The results showed that there were significant correlations between chlorophyll content in leaf and its corresponding reading measured by SPAD-502 for the three tree species, and the chlorophyll content increased with increasing stand density. Nutrient contents in high-density stands was the highest for Acacia auriculiformis stands, whereas they were the highest in middle-density stands and the lowest in high-density stands for Michelia macclurei stands. The N and Mg contents were high and P content was low in Acacia auriculiformis leaves, K and Ca contents were high and Mg content was low in Michelia macclurei leaves, whereas P content was high and N and K contents were low in Rhodoleia championii leaves.