The effect of gamma radiation on seed germination and seedling growth of Lathyrus chrysanthus Boiss. under in vitro conditions

The effects of radiation at different doses (0, 50, 100, 150, 200 and 250 Gy) of radioactive cobalt (⁶⁰Co) γ rays on seed germination and seedling growth of Lathyrus chrysanthus were investigated under in vitro conditions. The results showed that irradiated seeds had increased seed germination percentage, seedling and root lengths, seedling fresh weight, seedling dry matter content and total chlorophyll content in the leaves of seedlings. However, at higher doses stress was evident and significant decreases in all parameters were observed. The highest seed germination percentage was recorded as 62.4%, 7 days after study initiation when seeds were irradiated with 150 Gy gamma dose, while 100 Gy gamma dose was ranked in second order. Fourteen days after culture initiation, the best shoot growth initiation was again obtained from 150 Gy gamma dose as 75.7% and this was followed by 100 Gy gamma radiation as 74.6%. Gamma doses over 150 Gy resulted in sharp decreases in all parameters examined. On the 14th day, the highest shoot and root lengths were recorded from 150 Gy gamma dose as 1.2 and 2.9 cm, respectively. Twenty eight days after study initiation, the highest values of seedling and root lengths, seedling fresh weight, seedling dry matter content and total chlorophyll content were noted from 50 Gy gamma radiation as 9.7 and 6.3 cm, 0.39, 0.09 g (23.08%) and 471.6 μg/g fresh tissue, respectively. This study is important from the aspect of showing that stimulatory effect of low gamma doses for germination and seedling growth may not be the same. - Highlights: • Low dose of gamma rays stimulates germination and shoot growth initiation in Lathyrus chrysanthus. • High level of gamma irradiation inhibits seed germination and seedling growth. • Low gamma irradiation encourages seedling growth and biomass production.