Effect of substrate and gibberellic acid (GA3) on seed germination in ten cultivars of Opuntia sps.
Keywords:cactus pear fruit, scarification, substrate, in vitro germination, ?-amylase
The seeds of Opuntia sps show low germination capacity and high latency, so this study
compares different inert and synthetic substrates in vitro with the addition of gibberellic acid
(GA3) to stimulate seed germination in ten cultivars of Opuntia sps. (O. megacantha, O.
amyclaea, O. streptacantha, O. albicarpa and O. ficus-indica). The photoperiod 16/8 h,
light/darkness had a positive stimulating effect on the seed germination rate, while an inert
substrate (pumice:peat moss:sand, 1:1:1 v/v) showed on average 20% germination. The use
of in vitro Gamborg medium increased the germination rate to 40%. The addition of 25 mg L-1
gibberellic acid (GA3) to Murashige and Skoog (1962) medium, prepared to ¼ basal salt
concentration, increases the germination rate across all cultivars, up to 90% at four weeks.
GA3 was shown to play an important role in breaking the latency of the seed, and increased
amylolytic activity during seed germination in Opuntia sps.