Micropropagação e endorreduplicação em pitaya vermelha, Hylocereus undatus Haw

Abstract

Micropropagation makes the obtaining of seedlings of red pitaya easier, but, it can cause genetic mutations such as polysomaty, endopolyploidy or endoreduplication. In this work, it was aimed to develop a protocol for micropropagation and check the endoreduplication in red pitaya. Pitaya cladodes were micropropagated im MS culture medium with 0.1 mg L-1 of ANA added of BAP and kinetin at the dosages of 0, 1, 5 and 10 mg L-1, the MS medium without any growth regulators being used as the control treatment. The experimental design utilized was the completely randomized in factorial 2 x 8 (absence and presence of light and 8 different culture media), amounting to 16 treatments, namely, 4 replications of 3 explants. The experiment was conducted in the presence and absence of light in a growth room at 25 ± 2 ºC, average irradiance of 42W m-2 and photoperiod of 16 hours for 120 days. The flow cytometry analysis was utilized on three explants per treatment. Cladode samples, along with the internal pattern (pea) were ground with 1 ml of extraction buffer LB 01 and 25 mL of propide iodide, analyzed in flow cytometer. The explants submitted to the absence of light did not respond to the treatments. The culture medium which brings about the best in vitro growth and development is the MS added of 0.1 mg L-1 of ANA and BAP or kinetin at the concentrations of 1 or 0.5 mg L-1. The culture medium which provides to the explants greatest variation in the amount of DNA is MS with 10 mg L-1 of BAP and 0.1 mg L-1 of ANA. The phenomenon of endoreduplication is found in all the treatments investigated.