Radiosensitivity and Biological Effects of Gamma and X-Rays on Germination and Seedling Vigour of Three Coffea arabica Varieties

Use of Low-dose Gamma Radiation to Promote the Germination and Early Development in Seeds

“…X-rays correspond to a non-nuclear IR of electromagnetic nature (similar to gamma rays) that has also been used to modify the behavior and development of various plant species. Regarding their use as a radio-stimulant agent, shorter germination times have been reported in Hibiscus [91], increased vigor of coffee seedlings [92], increased leaf area in Phaseolus plants [93], and increased leaf and plant size in Tomato [25] in response to doses ranging from 0.1 Gy to doses greater than 100 Gy.…”

Ionizing Radiation: Effective Physical Agents for Economic Crop Seed Priming and the Underlying Physiological Mechanisms

“…However, relatively few works have been published focusing on the effects of X-ray irradiation on seed priming in recent years [ 61 , 62 ]. The existing research relating to the stimulation effect is most associated with accelerating the seed germination, enhancing the seedling growth, earlier flowering, and increasing the crop yields by exposing the seeds or plants to low doses of X-rays [ 37 , 41 , 63 , 64 ]. The positive effects of the low dose of X-rays have been reported in Phaseolus vulgaris by Arena, and according to their research, the seeds exposed to 0.3 and 10 Gy significantly stimulated leaf lamina growth at 1 Gy/min, and the over-production of phenolic compounds in the cells may be a natural defense mechanism of the photosynthetic apparatus against radiation [ 42 ].…”

“…In addition, the research has revealed that 0.3, 10, 20, 50, and 100 Gy X-rays markedly improved the plants’ height, the number of leaves, and the plant leaf area of Solanum lycopersicum L., and they formed more compact plants [ 40 ]. Similarly, the optimum dose of X-rays to stimulate germination and seedling vigor was established in a study on Coffea arabica [ 41 ]. Although the percentage of the germination of the seeds was not promoted in any treatment, the increase in the toughness and the diameter of the corn’s roots ( Zea mays L.) were observed in a pre-sowing treatment with X-rays [ 65 ], while in other studies, irradiation produced a more uniform distribution of seedling heights in barley, and also, it increased the first emergence counts in broccoli ( Brassica oleracea L.) and parsnip ( Pastinaca sativa L.) [ 39 , 64 ].…”

“…The theoretical basis on how the X-rays impact the plants suggests that the irradiation causes DNA damage (mismatches, breaks, and cross-links), chromosome aberration, and the excessive production of ROS, leading to the damage of proteins, lipid membranes, and nucleic acids, affecting the growth and physiological parameters, and ultimately, the crop yield [ 37 , 98 , 99 ]. The response of the plants to the X-rays depends on the radiation quality (e.g., the doses and dose rate), the plant characteristics (e.g., the species and genome size), and the external conditions for growth (e.g., temperature and water) [ 40 , 41 , 100 , 101 ]. The effects that the X-rays have at elevated doses are to a large degree, harmful and hindering, however, some research indicates that low irradiation doses positively affect the growth of the plant and its productivity [ 41 , 42 , 102 , 103 ].…”

“…The response of the plants to the X-rays depends on the radiation quality (e.g., the doses and dose rate), the plant characteristics (e.g., the species and genome size), and the external conditions for growth (e.g., temperature and water) [ 40 , 41 , 100 , 101 ]. The effects that the X-rays have at elevated doses are to a large degree, harmful and hindering, however, some research indicates that low irradiation doses positively affect the growth of the plant and its productivity [ 41 , 42 , 102 , 103 ]. Under low-dose treatments, X-ray irradiation promotes the plants to synthesize enzymatic and non-enzymatic products effectively to remove excess ROS, including SOD, CAT, APX, POD, AsA, and GSH.…”