Growth and histological development of the fruit pericarp in rambutan (Nephelium lappaceumLinn.)

Abstract

Rambutan (Nephelium lappaceum Linn.), of the Sapindaceae family, is a fruit tree that grows in the humid tropics. After harvest, the fruit changes from bright red to dull brown in color and loses commercial value as the pericarp dehydrates. We studied the changes in the morphology and anatomy of pericarp during fruit development. The orchard from which the samples of rambutan fruits RI-148 were taken is located Tuxtla el Chico, Chiapas, Mexico, (lat. 14°58'N; long. 92°09'W; altitude 435 m), with an average annual temperature of 23°C, RH of 85% and 3,100 mm of rainfall. The results showed that the fruit had a sigmoidal pattern of growth, with an increase in total sugars in the aril from 8.7% on day 75 to 14.6% on day 95 after anthesis. The number of spinterns per fruit was constant (328±20), the number of stomata per spintern was about 3200 and about 1.0×106 fruit-1. The increase in length of the spinterns during development of the pericarp provides greater contact surface with the environment, which modifies the intensity of transpiration. Thickness of the pericarp cuticle halved from day 50 to day 100 after anthesis. Finally, the anomocytic stomata on the spinterns and pericarp, tended to stay open for the entire duration of fruit development, and consequently, the fruits experienced an acceleration in loss of moisture, dehydration, and color change (oxidation) during postharvest that shortened their shelf life.