The role of ethylene on direct shoot bud regeneration from mangosteen (Garcinia mangostana L.) leaves cultured in vitro

Abstract

The role of ethylene in the regulation of shoot bud regeneration from leaf explants of mangosteen (Garcinia mangostana L.) was studied by culturing leaf segments (2 mm) on woody plant medium supplemented with BA (20 μM), ethylene inhibitors AgNO3, AVG or ethylene precursor ACC, under aerated or airtight conditions. In aerated cultures, the first emergence of shoot buds occurred on midribs within 18 days of incubation and 92% of the explants regenerated buds by day 42. With airtight cultures sealed with rubber septa stoppers, a large accumulation of ethylene, callus production and a marked delay of at least 12 days in shoot bud regeneration were observed. The addition of ACC to the culture medium also dramatically delayed shoot regeneration and enhanced callus proliferation. Under airtight conditions, both AgNO3 and AVG were effective in preventing the delay of shoot regeneration and callus formation. However, only AVG suppressed ethylene production. Ethylene or ethylene inhibitors did not affect the percentage of regenerating explants after 49 days of culture. As ethylene only delayed the emergence of shoot buds, it is presumed to regulate some of the early developmental stages associated with shoot bud regeneration in mangosteen leaf explants.