Elucidation of the Radiosensitivity Level of Amorphophallus paeoniifolius (Dennst.) Nicolson Embryogenic Callus Induced by Gamma Ray Irradiation

Abstract

The tuber of Amorphophallus paeoniifolius (Dennst.) Nicolson (Araceae) has been receiving attention as an alternative food source. However, the tuber contains oxalate compounds which reduce the utilization of this species as a food material. Inducing genetic mutations using gamma ray irradiation followed by a selection process can be used to increase genetic diversity and produce genetically improved cultivars of A. paeoniifolius. To achieve an effective mutation through gamma ray irradiation, the threshold of the sensitivity level of particular tissues is necessary to be elucidated in advance. Hence, the objective of the current study was to determine the level of radiosensitivity of in vitro-cultured A. paeoniifolius embryogenic callus to gamma rays. The main treatment factor in this experiment was different levels of gamma ray irradiation, including 0, 5, 10, 15, and 20 Gy. Plant growth parameters, such as the number of roots, shoots, and leaves, and also the height of plantlets arising from the callus, were decreased by applying gamma ray irradiation. Importantly, applying irradiation doses greater than 15 Gy significantly decreased the proportion of surviving embryogenic calluses. The lethal doses 20, 30, and 50 (LD20, LD30, and LD50) of calluses were 1.75, 5.44, and 12.84 Gy gamma irradiation, respectively. Since the high frequency of mutation was previously often found in around LD20–LD50 irradiated callus in other plants, this present study suggested that the effective gamma irradiation of A. paeoniifolius embryogenic callus was between 1.75 Gy until 12.84 Gy.