Effect of Low Gamma Irradiation on the Germination and Morphological Characteristics of Broad Beans (Vicia faba L.), Mung Beans (Vigna radiata L.), and Peas (Pisum sativum L.) Seedlings

Abstract

Understanding the effects of ionising radiation (IR) on plants has been a major focus of research. Acute high-dose effects are well-documented and understood (mainly through laboratory testing). Lower doses, on the other hand, are less understood, as low dosage research is controversial, and there are only a few studies that use low and ecologically relevant IR levels, particularly those conducted under controlled conditions. The effect of low gamma radiation was investigated in this study using Vicia faba L., Vigna radiata L., and Pisum sativum L. Healthy and viable seeds of these plants were irradiated with varying doses of gamma radiation (Cs−137 source) and sown under controlled environmental conditions. The doses/dose rates used were within the scope of the International Commission on Radiological Protection’s Derived Consideration Reference Level (DCRL) for these groups of plants (1 - 10 mGy∙d−1), so this study tested this DCRL. Observations were made on certain germination parameters and growth traits like germination percentage and rate, shoot and root length, seed weight, number of leaves, wet and dry biomass, plant height, leaf chlorophyll content, and leaf area. In the germination phase, the doses employed in this experiment did not affect the seeds’ weight, germination percentage, and rate, but there were some interesting effects on the root and shoot length; as all irradiated groups performed better than the control group (particularly the 16.2 mGy and 48.5 mGy dose in V. radiata and P. sativum, while the 1070 mGy dose had the highest value in V. faba). However, the plants were able to compensate for the effects observed in the germination phase and by the end of the experiment, there were no statistically significant effects (at 0.05 p level) in all the morphometric parameters studied; the visible organs appeared normal, and growth rate was normal. This study, therefore, concludes that the DCRL used to protect these groups of plants from the effects of IR (1 - 10 mGy∙d−1) is appropriate and present regulation appears to be suitable.