161 Effects of Light Intensity on Leaf Anatomy of Some Tropical Fruit (Rambutan, Durian, Mangosteen, and Longkong)

Abstract

Leaf anatomy of young rambutan (Nephelium lappaceum Linn.), durian (Durio zibethinus Murray), mangosteen (Garcinia mangostana Linn.), and longkong (Aglaia dookoo Griff.) potted plants grown under different light intensity (100%, 55%, 40%, or 25% of full sun) were observed. The thickness of both palisade and spongy parenchyma decreased as the light intensity decreased. This resulted in a decrease of lamina thickness when the light was lower. An exception occurred in mangosteen when the thickness of both palisade and spongy parenchyma in leaf grown under full sunlight were lower than in leaves grown under 55% or 40% full sun. The thickness ratio of palisade and spongy tissue in rambutan and durian decreased as light intensity decreased. While the ratios in mangosteen and longkong leaves grown under full sunlight were lower than the ratios of leaves grown under 55% or 40% of full sun. The frequency of stomata also decreased as the light intensity decreased. The thickness of palisade tissue of leaves grown under 55% of full sun in rambutan, durian, mangosteen, and longkong were 70, 110, 110, and 55 μm, respectively. The thickness of spongy tissue of leaves grown under 55% of full sun in rambutan, durian, mangosteen, and longkong were 60, 30, 410, and 145 μm, respectively. The thickness of leaves grown under 55% of full sun in rambutan, durian, mangosteen, and longkong were 186, 230, 565, and 233 μm, respectively. The number of stomata per square millimeter of leaves grown under 55% of full sun in rambutan, durian, mangosteen, and longkong were 437, 221, 133, and 301, respectively. Photosynthesis efficiency and light adaptation were discussed.