Gamma Radiosensitivity Study on Long Bean (Vigna sesquipedalis)

Abstract

This study was conducted to determine the LD₅₀ and effect of gamma ray on germination percentage, plant height, survival percentage, root length, root dry weight and shoot dry weight of seedlings derived from seeds of long bean (Vigna sesquipedalis). Seeds of this crop were treated with 300, 400, 500, 600 and 800 Gy gamma rays at Malaysian Institute of Nuclear Technology (MINT). The treated seeds including control were sown in sand beds in size 4.6 x 0.7 m² in a greenhouse at Horticulture Unit, Universiti Putra Malaysia Bintulu Campus (UPMKB). After germination, plants were transferred into polybags. Each polybag contained 1.2 kg blended growth medium with top soil, sand, and processed chicken dung ratio of 3:2:1. Standard procedures were used to observe and record the variables studied in this research. The experiment was designed as a 4 x 6 factorial Completely Randomized Design with 3 replications. Lethal dose 50 % of population (LD₅₀) was assayed. The study revealed that germination percentage, plant height, survival percentage, root length, root dry weight and shoot dry weight decreased with increasing dose of gamma ray. The 800 Gy gamma ray dose in particular had a pronounced effect on these morphological characteristics probably because of injury it might have caused to the seeds of the long bean. As a result, poor growth and development was noticed. The LD₅₀ for survival and height ranged between 600-800 Gy and 400-500 Gy, respectively. Generally, higher gamma ray doses particularly 800 Gy significantly affected the morphological characteristics of long bean seedlings obtained from irradiated seeds.