RESPONSE OF SANDAL WOOD (Santalum album L.) LEAF EXPLANTS UNDER IN VITRO CONDITIONS

Abstract

Sandalwood is a commercially important plant species belonging to the family Santalaceae and
the genus Santalum. Sandalwood oil extracted from the heartwood has been used for medicinal,
cultural and other purposes. The objective of this study was to find out the in vitro regenerative
responses of sandalwood leaf explants using different combinations of plant growth regulators
such as BAP and 2, 4 D. Half immature leaf explants were excised vertically with midrib fromnewly formed shoots of two years old seedlings. They were then subjected to sterilize by using
70% ethanol for 30 sec and immersed in 25% CloroxTM (Sodium hypochlorite, 5.25% active
ingredient) with two drops of tween 20 for 20 min. Sterilized explants cultured on MS mediumsupplemented with different concentrations of (0.5–1.0 mg/l) BAP and 2,4 D and kept in
culture environment. The half immature leaf explants showed remarkablely higher (73.3%)
callus formation within four weeks of culture on MS medium containing 1.0 mg/l 2, 4 D and
after that there was no considerable proliferation in callus. Subcultured callus on MS mediumsupplemented with 1.0 mg/l BAP showed better callus proliferation. One fourth of half leaf
explant produced 73.6 ± 1.73 mg of callus mass and the colour was changed from greenish
yellow to light yellow at four weeks after subculture. Leaf explants were cultured on 1.0 mg/l
BAP exhibited yellowish white calli. Leaf explants near the margin produced more callus
compared with explants from the rest of the leaf lamina. Leaf lamina proximal to the leaf base
region responded well rather than distal area. The cells on both the sides of the midrib were
observed to be small in size and the cells towards middle of the leaf and towards the margin were
found to be larger. It can be concluded that MS medium containing 1.0 mg/l BAP was more
suitable to produce embryogenic callus from immature leaf explants of sandalwood.

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