Control of media browning in micropropagation of guava (Psidium guajava L.)

Guava (psidium guajava l.) is a highly valuable fruit of the tropical regions of the world. this species faces browning or blackening of culture medium during in vitro culture due to leaching of phenolic,microbial contagion and tissue recalcitrance. a study therefore designed to evaluate the effects of antioxidants in reduction of phenolic exudation which hampers in vitro regeneration. the nodal explants of the plant were cultured on ms media after pre-soaking in antioxidant solutions of citric acid,ascorbic acid,poly vinyl pyrrolidine (pvp) and charcoal. after culturing explants,the amount of phenolic exude was determined periodically on spectrophotometer at 750 nm absorbance. phenolic exudation from guava was significantly reduced in nodes treated with charcoal as compared to control and rest of the treatments. moreover,guava nodes survival percentage was also significantly increased in charcoal treated nodes. it is concluded that pre-soaking in different antioxidants significantly reduced the media browning and thus micro-propagation of guava could be achieved on commercial basis. © 2016,pakistan botanical society. all rights reserved.