Effect of Plastic Bagging on Growth and Nutrient Contents of Mangosteen Fruit

The objective of this study was to investigate the impact of limited transpiration on fruit growth and nutrient accumulation in mangosteen and to determine the critical period when nutrient accumulation was most affected. The limiting transpiration was simulated by bagging the mangosteen fruits with polypropylene plastic bags on a weekly basis during the first four weeks after fruit set. The bags remained on the fruits until the fruits were collected at the rapid fruit growth stage (age 7 weeks) and at maturing stage (age 12 weeks) together with the non-bagged control fruits. Fruit dry weight, fruit diameter and nutrient concentrations were determined. Bagging at the first two weeks after fruit set significantly lowered the fruit size and dry weight, whereas bagging at the fruit age of 4 weeks showed no effect. Fruit concentrations of K, Ca, Mg and B were not affected by all bagging treatments at both stages of fruit development. Accumulation of K, Ca, Mg and B during the first 7 weeks of fruit growth was significantly reduced by all bagging treatments. The earlier the fruits were bagged, the lower nutrient accumulation. In the final 5 weeks of fruit growth, only Ca and B were affected by bagging during the first 3 weeks after fruit set. The results confirmed that limited fruit transpiration could restrict Ca and B uptake into fruit and result in Ca and B deficiencies. The results suggest that the most critical period for Ca and B accumulation was the first 3 weeks after fruit set.