Meteorological Conditions of Mangosteen Orchard in West Java, Indonesia and Seasonal Changes in C-N Ratio of Their Leaves as Affected by Sector (Position in Canopy) and Tree Age

Productivity and quality of mangosteen fruit is markedly affected by tree age and sector (position in canopy). The objective of this study was to make clear seasonal changes in meteorological conditions of mangosteen orchard, and C-N ratio of leaves in relation to tree age and sector. The experiment was conducted using mangosteen trees grown in commercial orchard in Bogor, Indonesia during May to October 2010. Mangosteen trees of 3 different ages, young (20-year-old), middle (35-year-old), and old (50-year-old), each of five trees, were selected for study, and the canopy of each tree was divided into 9 sectors based on height (bottom, middle, top) and width (inner, center, outer). The light intensity on sunny days was higher in Sector 9, it was 8.1, 7.5, and 7.7 μmol・M(−2)・s(−1) in young, middle-aged and old trees, respectively, whereas in Sector 1 it was low, resulting 0.5, 0.4, and 0.5 μmol・M(−2)・s(−1) in young, middle-aged and old trees, respectively. Regardless of tree age, light intensity in outer position in canopy was higher than in the inner, and also it was higher in taller than in lower positions in canopy. In 2010, the phenological aspects of mangosteen orchard markedly changed because of irregular rainfall. In spite of tree age, SPAD value of leaves in upper parts such as Sectors 5-9 was high comparing with lower ones such as Sectors 1-4. In young trees, carbohydrate content of leaves was higher in top positions such as Sectors 7-9 than in bottom ones such as Sectors 1-3, whereas in middle-aged and old trees, no significant difference of carbohydrate content was observed among sectors. Regardless of month and tree age measured, nitrogen content of leaves was higher in lower positions in canopy such as Sectors 1-4 than in upper ones such as Sectors 5-9. Consequently, the C-N ratio of leaves was higher in the upper part of canopy compared to the lower. Based on the results, the relationships between meteorological status and C-N ratio of leaves and fruit productivity and quality of mangosteen are discussed in relation to position in canopy and tree age.

原著論文 (Original paper)