Sunflower germination and growth behavior under various gamma radiation absorbed doses

Application of gamma irradiation on morphological, biochemical, and molecular aspects of wheat (Triticum aestivum L.) under different seed moisture contents

Nuclear technology is currently used as a tool in mutation breeding to improve crops by increasing genetic variation. The ionization of gamma rays produces large amounts of free radicals, simulating stressors in the natural environment. To avoid gamma-ray-induced oxidative stress, plants use antioxidant defense systems. Exposure of plants to irradiation can affect the germination, growth, and production of metabolites. Plants' sensitivity to irradiation depends on genetic and environmental factors such as moisture content. For this purpose, the effects of different gamma irradiation doses [0, 100, 200, 300, and 400 Gray (Gy)] and different seed moisture contents (7, 13, and 19%) on traits such as seed germination, seedling growth, molecular and biochemical alterations in antioxidant enzymes were examined in the current study. Based on the results, the highest seed germination percentage was observed in the interaction effect of seed moisture at 13% with an irradiation dose of 400 Gy (98.89%). Seedling survival percent and seedling length decreased with increasing doses of gamma irradiation at different seed moisture contents. Increasing gamma irradiation doses were reduced root and stem fresh and dry weight, and root and stem length. The highest level of catalase enzyme activity and expression was observed at 200 and 300 Gy irradiation doses at different moisture contents. The peroxidase and polyphenol oxidase gene expression were reduced at all contents of gamma irradiation doses and seed moisture compared to the control. It can be concluded that the dose of 200-300 Gy of gamma irradiation reduced plant growth by 30% in terms of fresh and dry weight and length of plants, as well as enhanced the expression of antioxidant enzymes. The results of this study could help plant breeders select an appropriate dose rate in wheat for further research.

Morphological characterization and expression analysis of genes for antioxidants enzymes in gamma rays induced M3 mutants of sunflower (Helianthus annuus L.) cultivar TNAUSUF-7

PURPOSE

Objectives of the present investigation were to investigate the performance of mutant lines (mutant generation 3 (M3) generation) of sunflower obtained through gamma irradiations for yield and yield attributing traits including oil content (%), oil quality in terms of antioxidant activity and to investigate the expression of genes encoding antioxidant enzymes in control and gamma irradiated M3 lines.

MATERIALS AND METHODS

Mutant lines (M3 generation) of sunflower variety TNAUSUF-7 obtained from 100 and 130 Gray (Gy) doses of gamma irradiation were evaluated for several traits such as days to 50% flowering, days to maturity, head diameter, number of filled seeds and unfilled seeds per head, fertility %, oil content %, antioxidant activity of oil and expression of genes encoding antioxidant enzymes. All the data were analyzed using different statistical tools.

RESULTS

Our results showed that the gamma irradiation dose of 100 and 130 Gy induced significant variations in yield and yield attributing traits especially for days to 50% flowering, days to maturity, fertility %, antioxidant property of sunflower seed oil and expression of genes encoding antioxidant enzymes.

CONCLUSIONS

From our results, it can be concluded that the gamma irradiations were effective in creating variations in terms of several traits in sunflower. Many desirable traits like reduced days to 50% flowering and maturity, increased fertility %, increased antioxidant activity of oil were observed in M3 lines. These M3 lines have the potential to be utilized as an inbred line in sunflower hybrid development or it could be used as a source of desirable traits in sunflower breeding programs.

Gamma-irradiated fenugreek extracts mediates resistance to rice blast disease through modulating histochemical and biochemical changes

The impact of gamma radiation on the activation of rice innate immunity to blast disease caused by Magnaporthe oryzae is described. In the present study, fenugreek seed extracts radiated with different doses of gamma rays viz. 5Gy, 10Gy, 15Gy, 20Gy and 25Gy were examined for their presence of biocompounds as well as for its ability to induce plant growth promotion and resistance against rice blast disease. The results of GC-MS analysis detected antimicrobial properties in methanolic extract. Enhanced germination (97%) and vigor (2718) was noticed in seeds pretreated with 20 Gy of gamma radiation in comparison with non-irradiated controls. Under greenhouse conditions, a significant disease protection of 56.7% on 3rd and 4th day after inoculation against rice blast was observed in 15Gy-irradiated rice plants challenge-inoculated with M. oryzae. Further, a significant increase in the hydrogen peroxide, phenol and lignin deposition was noticed in 20Gy-irradiated rice plants. Additionally, rice plants pretreated with 15Gy induced maximum activities of peroxidase (POX) and polyphenol oxidase (PPO) compared to untreated control plants. These findings revealed that rice plants-pretreated with gamma radiation elicit resistance against rice blast disease as well as strengthening the growth parameters by modulating cellular and biochemical defense system.

Gamma irradiation protect the developing wheat endosperm from oxidative damage by balancing the trade-off between the defence network and grains quality

Gamma irradiation has been reported to modulate the biochemical and molecular parameters associated with the tolerance of plant species under biotic/ abiotic stress. Wheat is highly sensitive to heat stress (HS), as evident from the decrease in the quantity and quality of the total grains. Here, we studied the effect of pre-treatment of wheat dry seeds with different doses of gamma irradiation (0.20, 0.25 and 0.30 kGy) on tolerance level and quality of developing wheat endospermic tissue under HS (38 °C, 1 h; continuously for three days). Expression analysis of genes associated with defence and starch metabolism in developing grains showed maximum transcripts of HSP17 (in response to 0.25 kGy + HS) and AGPase (under 0.30 kGy), as compared to control. Gamma irradiation was observed to balance the accumulation of H₂O₂ by enhancing the activities of SOD and GPx in both the cvs. under HS. Gamma irradiation was observed to stabilize the synthesis of starch and amylose by regulating the activities of AGPase, SSS and α-amylase under HS. The appearance of isoforms of gliadins (α, β, γ, ω) were observed more in gamma irradiated seeds (0.20 kGy), as compared to control. Gamma irradiation (0.25 kGy in HD3118 & 0.20 kGy in HD3086) was observed to have positive effect on the width, length and test seed weight of the grains under HS. The information generated in present investigation provides easy, cheap and user-friendly technology to mitigate the effect of terminal HS on the grain-development process of wheat along with development of robust seeds with high nutrient density.

Effect of gamma radiation on storability and functional properties of sorghum grains (Sorghum bicolor L.)

This study was aimed to evaluate the effect of gamma irradiation at dose levels of 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 kGy on fungal growth, free fatty acids, in vitro protein digestibility (IVPD), protein solubility, and functional properties of sorghum grains. Results indicated that radiation process enhanced the storability properties. It eliminates the fungal incidence particularly at the higher doses 4.0 and 5.0 kGy, and significantly (p < 0.05) reduced the content of the free fatty acids to the level 3.4-3.2 mg/g. Moreover, a significant increase in IVPD and soluble protein was noticed in irradiated grains as compared to non-irradiated sample and this increased with the increase in dose; however, maximum IVPD (17.6%) and protein solubility (11.7%) were observed in sorghum grains irradiated at 2.0 kGy. On the other hand, a significant reduction in emulsion capacity was observed after radiation of grains, however, the emulsion activity and stability were stable up to 1.0 kGy. The foaming properties of the radiated sample show no significant change particular at low doses up to 2.0 kGy when they are compared to untreated samples. It can be concluded that low doses of gamma irradiation might improve the storability and quality characteristics of sorghum grains and can be used as an effective alternative postharvest method for preserving and extending the shelf life of sorghum and its products.