Evaluation of Abiotic Stress Response in In Vitro Culture of Hylocereus undatus

Abstract

Hylocereus undatus or white dragon fruit is a vine-like cactus that is commonly grown as both an ornamental plant and a fruit crop. However, their response to various abiotic stresses is understudied. Once transferred to the soil, the plants are exposed to different abiotic stresses caused by extreme salinity, drought, pH changes, and oxidative responses. This will either affect its growth or fruit production. The present study aims to evaluate the effects of various abiotic stress which are common in agricultural areas in vitro. The seeds of white dragon fruit were germinated in Murashige and Skoog (MS) basal medium supplemented with of 2.0 mg/L  6-benzylaminopurine (BAP) and 0.5 mg/L 1-Naphthaleneacetic acid (NAA) before the shoots formed were induced in MS with different abiotic stress which were drought, salinity, pH and oxidative stress. The shoot and the root length were recorded at the fourth week of culture. Interestingly, slight drought stress with 20 g/L polyethylene glycol (PEG) 8000 induced shoot growth but further increase of PEG 8000 reduced shoot length significantly. Shoot length was the most inhibited at 200 mM NaCl and root failed to grow at this concentration. Shoot and root growth under pH stress was the lowest at pH 8. The length of shoot and root under oxidative stress were seen to decrease gradually with increase of H₂O₂ concentration but this was only significant in roots. In conclusion, roots were more vulnerable to some abiotic stresses than shoots were. A greater magnitude of stressors can be tested for further information of H. undatus tolerance to abiotic stresses.