Low dose gamma radiation effects on seed germination and seedling growth of cucumber and okra

Arabidopsis telomerase takes off by uncoupling enzyme activity from telomere length maintenance in space

Spaceflight-induced changes in astronaut telomeres have garnered significant attention in recent years. While plants represent an essential component of future long-duration space travel, the impacts of spaceflight on plant telomeres and telomerase have not been examined. Here we report on the telomere dynamics of Arabidopsis thaliana grown aboard the International Space Station. We observe no changes in telomere length in space-flown Arabidopsis seedlings, despite a dramatic increase in telomerase activity (up to 150-fold in roots), as well as elevated genome oxidation. Ground-based follow up studies provide further evidence that telomerase is induced by different environmental stressors, but its activity is uncoupled from telomere length. Supporting this conclusion, genetically engineered super-telomerase lines with enhanced telomerase activity maintain wildtype telomere length. Finally, genome oxidation is inversely correlated with telomerase activity levels. We propose a redox protective capacity for Arabidopsis telomerase that may promote survivability in harsh environments.

X-radiation of Lotus corniculatus L. seeds improves germination and initial seedling growth

PURPOSE

Lotus corniculatus L. (bird's foot trefoil, BFT) is a valuable perennial legume forage species due to its high nutritive value, persistence under grazing, and condensed tannin content that improves ruminant production and prevents bloating. However, it is less preferred by farmers compared with other perennial forage legumes such as alfalfa because of slow germination, slow establishment and low seedling vigor. This study was conducted to determine whether X-ray seed priming could improve these deficiencies.

MATERIALS AND METHODS

Seeds of L. corniculatus cv. 'AC Langille' were irradiated at 0, 100, and 300 Gy. Non-irradiated and irradiated seeds were sown on Murashige and Skoog/Gamborg medium under in vitro conditions and cultured for 21 days. Germination percentage, mean germination time (MGT), germination rate index, length of shoot and root, fresh and dry weight of shoot and root, dry matter ratios of shoot and root, water content of shoot and root, and seedling vigor index were measured.

RESULTS

The results of this study demonstrated that X-ray seed priming significantly increased the germination percentage of L. corniculatus, increased the germination rate and thereby shortened the MGT, and improved seedling growth. However, X-ray pretreatment also decreased seedling shoot and root biomass.

CONCLUSIONS

In this study, it is reported for the first time that X-ray seed pretreatment has the potential to address important seedling establishment issues in L. corniculatus.

Beneficial effects of gamma-irradiation of quinoa seeds on germination and growth

Quinoa is one of the crops well-adapted to high altitude regions that can grow relatively well under drought, humid, and high UV radiation conditions. This study was performed to investigate the effects of gamma-radiation on quinoa. Seeds were treated with various doses of 50 Gy, 100 Gy, 200 Gy, 300 Gy, 400 Gy, 600 Gy, 800 Gy, and 1000 Gy. We investigated germination, as well as plant height, chlorophyll content, and normalized difference vegetation index (NDVI) at 0, 30, 44, 58, and 88 days after transplanting (DAT) and panicle weight at 88 DAT. The plants grown from the seeds treated at radiation doses greater than 200 Gy showed reduced values in most growth and physiological characteristics. The germination rate and germination speed were higher in the 50 Gy-treated seeds than in 0 Gy-treated (control) seeds. Plant height and panicle weight were highest in the plants from 50 Gy-treated seeds. Chlorophyll content was higher in all treated samples than in the controls. NDVI value showed the highest value in 0 Gy controls and plants treated with 50 Gy. The antioxidant activity was also higher in the plants from the seeds treated with 50 Gy and 100 Gy, showing a steady increase as the radiation dose increased even at 200 Gy. The plants from seeds treated with 0 Gy showed higher expression of proteins related to photorespiration and tubulin chains. The plants from seeds treated with 50 Gy induced more stress-responsive proteins.

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.