Irradiated Seeds Research Articles

The Impact of Supplemental UV-B Radiation on Growth and Biochemical Constituents in Vigna unguiculata L. Walp and Pisum sativum L.

This study investigates the impact of UV-B radiation on plant growth and biochemical constituents in Vigna unguiculata and Pisum sativum plants grown from non-irradiated and UV-B-irradiated seeds. The results show that plants grown from UV-B-irradiated seeds for 30, 60, and 90minutes experienced significant reductions in plant height, root length, and shoot length compared to non-irradiated seeds. Additionally, plants with UV-B-irradiated seeds had less fresh and dry weight. The decline was particularly pronounced in plants exposed to UV-B radiation for 90minutes. Chlorophyll a, b, and total chlorophyll (a+b) dropped significantly in plants grown from seeds exposed to UV-B radiation for 30, 60, and 90minutes. The reduction was particularly significant in plants exposed to UV-B radiation for 90minutes. Moreover, plants with higher levels of total free phenolics and tannins had higher contents compared to non-irradiated seeds. The level of total free phenols is higher in irradiated seeds of P. sativum than V. unguiculata. The plants exposed to UV-B radiation for 90minutes showed a noticeable increase.

Exogenous Brassinolide Ameliorates the Adverse Effects of Gamma Radiation Stress and Increases the Survival Rate of Rice Seedlings by Modulating Antioxidant Metabolism.

Gamma irradiation-based mutant creation is one of the most important methods for rice plant mutagenesis breeding and molecular biology research. Although median lethal dose irradiation severely damages rice seedlings, applying brassinolide (BR) can increase the survival rate of irradiated seedlings. In this study, we investigated the effects of soaking seeds in solutions containing different BR concentrations (0.001, 0.01, 0.1, 1.0, and 5.0 μmol/L) and then spraying the resulting seedlings twice with 0.1 μmol/L BR. The combined BR treatments markedly decreased the superoxide anion (O2•-), hydrogen peroxide (H2O2), and malondialdehyde contents but increased the chlorophyll content. An appropriate BR treatment of gamma-irradiated samples substantially increased the activities of the antioxidant enzymes superoxide dismutase, peroxidase, and ascorbate peroxidase as well as the proline, ascorbic acid, and glutathione contents in rice seedling shoots. The BR treatment also promoted the growth of seedlings derived from irradiated seeds and increased the shoot and root fresh and dry weights. Most notably, soaking seeds in 0.01 or 0.1 μmol/L BR solutions and then spraying seedlings twice with 0.1 μmol/L BR significantly increased the final seedling survival rate and decreased mutant loss. The study results suggest that exogenous BR treatments can protect rice seedlings from gamma irradiation stress by enhancing antioxidant metabolism.

Moringa olifera leave extracts yielded from irradiated and unirradiated seeds cause toxicity and induce dysregulation of enzymatic activities in fall armyworm, Spodoptera frugiperda (JE Smith, 1797) [Lepidoptera: Noctuidae]

The fall armyworm, Spodoptera frugiperda is the most distractive polyphagous noctuid pest in tropical and subtropical regions. The current study was designed to examine the insecticidal activity of the water extract of Moringa olifiera leaves cultivated from unirradiated and 40 Gy irradiated seeds. Also, the effect of the extract on some digestive enzymes activities was assayed. The results indicated that the extract produced from 40 Gy irradiated seeds was more effective than those of unirradiated one. As well as, leaves extract produced from cultivated irradiated and unirradiated seeds decrease lipase protease and amylase activities of 3rd instar larvae of S. frugiperda and the highest decrease was in larvae fed on leaves produced from irradiated cultivated seeds. Therefore, the water extract of M. olifiera leaves cultivated from 40 Gy irradiated seeds might be seen as an environmentally beneficial pest management method.

Biological responses of an elite centipedegrass [Eremochloa ophiuroides (Munro) Hack.] cultivar (Ganbei) to carbon ion beam irradiation.

Carbon ion beam irradiation (CIBI) is a highly efficient mutagenesis for generating mutations that can be used to expand germplasm resources and create superior new germplasm. The study investigated the effects of different doses of CIBI (50 Gy, 100 Gy, 150 Gy, 200 Gy and 300 Gy) on seed germination and seedling survival, seedling morphological and physiological traits of an elite centipedegrass cultivar Ganbei. The results showed that irradiation greater than 50 Gy cause inhibition of seed germination, and the semi-lethal dose (LD50) is around 90 Gy for CIBI treated seeds of Ganbei. A carbon ion beam-mutagenized centipedegrass population was generated from Ganbei, with irradiation dosages from 50 Gy to 200 Gy. More than ten types of phenotypic variations and novel mutants with heritable tendencies mainly including putative mutants of stolon number, length and diameter, of internode length, of leaf length and width, of leaf chlorophyll content, of stolon growth rate, of aboveground tissue dry weight, of sward height were identified. While the total sugar content of the plants from irradiated seeds showed no obvious change in all treatments as compared to the control, the crude protein content displayed significant reduction at a high-dose treatment of 200 Gy. Genetic polymorphism was detected in mutagenized centipedegrass population using SSR-PCR analysis, suggesting that CIBI caused alteration of larger fragments of the DNA sequence. As a result, a preliminary batch of mutants was screened in this study. In summary, carbon ion beam mutagenesis is an effective way for developing centipedegrass germplasm with wider variation, and treating seeds with CIBI at a dosage of ~100 Gy could be effective in centipedegrass mutation breeding.

Strategy to increase the growth of sweet banana varieties of chili (Capsicum sp) using Gamma Ray Radiation

Chili (Capsicum sp) is a herbaceous plant from the eggplant family and is thought to originate from Mexico, Central America, and the Andes region in South America. This research was carried out from November 2023 to May 2024. Sweet Banana Variety Chili Seeds were sent to the Isotope Application Center and Radiation (PAIR), National Nuclear Energy Agency (BATAN) Jl. Lebak Bulus Raya No.49 Cilandak-South Jakarta. Irradiated seeds were planted in the Green House of Labuhanbatu University, Labuhanbatu Regency, North Sumatra. The design used was a non-factorial completely randomized design (CRD) with 5 replications. The experiment used a single factor, namely gamma rays, on sweet banana variety chili seeds with 4 treatment levels: Control (0 Gy), 100 Gy, 200 Gy, 300 Gy. In this study, 20 plant units were observed. Based on the results of observations of the growth of sweet banana variety chili seedlings, seedling growth was different in each treatment, and most of the seedlings were only able to survive at an irradiation level of 100 Gy. The results of the analysis of variance showed that the gamma-ray radiation factor was significantly different from the number of leaves (strands) in the 2nd week after planting, but was not significantly different 4 weeks after planting. The results of the analysis of variance showed that the gamma-ray radiation factor was significantly different 2 weeks after planting, a further DMRT test was carried out at a level of 5%.

CAD1 contributes to osmotic tolerance in Arabidopsis thaliana by suppressing immune responses under osmotic stress

Acquired osmotolerance induced by initial exposure to mild salt stress is widespread across Arabidopsis thaliana ecotypes, but the mechanism underlying it remains poorly understood. To clarify it, we isolated acquired osmotolerance-deficient 1 (aod1), a mutant highly sensitive to osmotic stress, from ion-beam–irradiated seeds of Zu-0, an ecotype known for its remarkably high osmotolerance. Aod1 showed growth inhibition with spotted necrotic lesions on the rosette leaves under normal growth conditions on soil. However, its tolerance to salt and oxidative stresses was similar to that of the wild type (WT). Genetic and genome sequencing analyses suggested that the gene causing aod1 is identical to CONSTITUTIVELY ACTIVATED CELL DEATH 1 (CAD1). Complementation with the WT CAD1 gene restored the growth and osmotolerance of aod1, indicating that mutated CAD1 is responsible for the observed phenotypes in aod1. Although CAD1 is known to act as a negative regulator of immune response, transcript levels in the WT increased in response to osmotic stress. Aod1 displayed enhanced immune response and cell death under normal growth conditions, whereas the expression profiles of osmotic response genes were comparable to those of the WT. These findings suggest that autoimmunity in aod1 is detrimental to osmotolerance. Overall, our results suggest that CAD1 negatively regulates immune responses under osmotic stress, contributing to osmotolerance in Arabidopsis.

Induction of genetic variability of maize genotypes through radiation revealed mutants resistant to maize streak disease

The absence of genetic variability among crop genotypes is an impediment to breeding progress, hence mutagenesis could serve as a useful tool to create genetic variation to obtain desirable traits of interest. In this study, four maize genotypes, Obatampa, Dapango, Pann 54 and Honampa which were susceptible to maize streak disease (MSD) were acutely irradiated at 254.3 Gy, using a cobalt 60 (60Co) at a rate of 300 Gy/hr. The irradiated seeds were planted with their parental controls at streak disease highly endemic environment. Field trials for the selected maize genotypes were conducted from the M1 to M4 generations to screen for MSD resistance and improved grain yield. Sixteen putative mutants and four individual parental controls were selected across the four maize genotypes at the end of the M4 generation based on disease severity score and yield indices. Detailed morphological screening and field evaluation of putative mutants showing improved plant architecture, increased grain yield and resistance to maize streak disease were tagged and selected. Obatanpa-induced-genotype was the best mutant identified with a grain yield of 6.8 t ha−1. Data on days to 50% flowering indicated that all 16 putative mutants were maturing plants.

Effects of Different Levels of Gamma Radiation on Growth and Yield Characteristics of Groundnut

One of the key strategy for improving the crops is plant mutation breeding, which generates a large germplasm pool to improve crop characteristics. In this field experiment, the effects of different levels of gamma radiation on the growth and yield characteristics of groundnut were investigated. "Gamma chamber 1200 Cobalt-60" research irradiator was used to irradiate the groundnut seeds. Two experiments were conducted, with the first exposing the seeds to gamma radiation levels ranging from 0 to 100 Gy, and the second exposing them to levels from 0 to 500 Gy. Irradiated seeds were sown in poly bags and kept under shade. After 2 weeks, seedlings were transplanted in an open field using a Randomized Complete Block Design with five replications. Growth and yield parameters were collected, and statistical analysis was carried out using SAS 9.1 software, with treatment means compared using DMRT at 0.05 level. Results from experiment one showed no significant (P ≥ 0.05) differences among treatments. However, in experiment two, treatments showed significant differences in the measured variables. Seeds exposed to 200 Gy had increased shoot fresh weight (123.3%), root fresh weight (69.8%), number of pods (46%), 100-seed weight (47.7%), and total yield (65.6%). The study recommends 200 Gy as a more suitable level of gamma radiation to create desirable characteristics in groundnut. In conclusion, gamma radiation can be an effective tool for inducing mutations in plants for crop improvement. The findings of this radiation study could contribute to the improvement of new cultivars of groundnut with desirable traits, such as increased yield and improved plant growth.

Применение ультрафиолета для предпосевной обработкой семян

Modern methods of pre-sowing seed treatment disinfect seeds, increase yield and plant resistance to adverse environmental factors, and stimulate plant immunity. Among the methods of electromagnetic impact on bioobjects, irradiation of seeds with ultraviolet light is simple, energy-efficient, economically beneficial and environmentally safe. The research aimed to study the effect of UV irradiation for pre-sowing treatment of thuja seeds and empirically determine the effective dose of UV irradiation. To maintain the required UV irradiation dose, the authors developed a digital control system on ATMEGA128A microcontroller (ATMEL). The working area of a 12 × 12 UV matrix consisting of 200 UV LEDs was 144 cm2 . The distance from the UV LEDs to the irradiated seeds was about 2 cm. The UV dose of the matrix was controlled by monitoring the voltage drop on the NSL-19M51 photoresistors. The irradiance of the LEDs in the UV-A (UV-A) zone corresponded to 98%. In each series, 100 seeds of thuja occidentalis were irradiated; the experiments were repeated four times. The authors studied UV irradiation doses of 2 kJ/m2 , 3 kJ/m2 , and 4 kJ/m2 . Seeds of thuja occidentalis without UV irradiation treatment were used as a control. The effective dose of UV-irradiation of seeds was determined empirically. The determined UV irradiation dose of 2 kJ/m2 is able to increase seed germination energy by 12.8% as compared to the control. Statistical processing of empirical data showed satisfactory accuracy of the conducted experiments. The accuracy index of the experiment amounted to P=1.76%±0.65%, for the control (without UV irradiation) - P=1.33±0.47%.

Development of Mungbean Genotypes for Shattering Tolerance and Correlation Analysis with Biochemical and Morphological Factors Governing Pre Harvest Sprouting

Background: Most of the mungbean genotypes are prone to shattering. The indeterminate flowering habit of this crop leads to a spread of flowering and pod maturity on a single plant over the entire reproductive phase. Consequently, pods which develop at the earliest flower may shatter prior to 100% pod maturity. Sometimes losses due to pre-harvest sprouting will be as high as 60-70%. High yielding varieties developed/identified in recent years, despite their high yield potential, could not increase/stabilize the yields of this crop due to lack of resistance to pre-harvest sprouting. Therefore, an attempt was essentially made to develop tolerant varieties to pre-harvest sprouting in the current investigation. Methods: The F2 (Healthy and well dried) seeds derived from the crosses DGGV-2 ´ Pant Moong-1 were irradiated with 60 kR gamma rays for the creation of desirable variability. The gamma rays irradiated seeds were sown in during kharif-2017 along with their respective checks to grow the F2M1 generation. Further advanced to F2M2. The individual plants were critically observed at maturity for morphological traits viz., small pod beak length and angle, thick pod wall and hard seededness that determine the tolerance to PHS. The mutant lines were compared with the parental lines viz., shattering tolerant variety Pant Moong-1 as well as susceptible variety DGGV2. The putative mutants selected and tagged in F2M2 and the seeds were harvested separately and forwarded to develop the F2M3 mutant population (1000 plants) in summer-2018. The seeds from F2M3 generation were harvested on individual plant basis and were sown. 806 progenies were sown in augmented design along with the checks in each block during kharif 2019. Thus from the population of 24812 such derived plants, genotypes with small pod beak and angle, thick pod wall, hard seededness and higher epicuticular wax and lignin content were isolated in F2M3 and F2M4. Further a total of 49 advanced breeding lines along with a known shattering susceptible check were studied for the morphometric and biochemical parameters governing the pre harvest sprouting. Result: Lower PHS was recorded in DGGV-79 (0.02%), DGGV-125 (0.02%) and DGGV 195 (0.91%). Higher phenol content was recorded in DGGV-125 (9.43 mg GA eq /g) and DGGV-79 (9.37 mg GA eq /g). Higher lignin content was recorded in DGGV-125 (6.42 mg/g) and DGGV-79 (6.10 mg GA eq /g). Further correlation analysis revealed that negative correlation of PHS was observed for epicuticular wax (r= -0.983), phenol (r= -0.892), lignin content (r= -0.981) and hard seed percentage (r= -0.942). Significant negative correlation was observed between PHS and pod wall thickness (r= -0.570). Pod beak length recorded highly significant positive correlation (r= 0.911) to PHS. Genotypes with inherent tolerance to seed shattering hold a promise to minimize yield losses due to viviparous germination.

Meiotic analysis of induced translocation heterozygotes in Lepidium sativum Linn.

Aim: To assess the cytological effects of Gamma rays on the pollen mother cells and post meiotic products of Lepidium sativum Linn. which resulted in isolation of translocation heterozygote and aneuploid gametes. Methodology: During the experiment, parameters such as Meiotic stages, chromosomal structure, and pollen fertility were studied. Fresh seeds of Garden cress were orderly arranged in plastic and divided into four groups. The fresh seeds of each group were individually irradiated with 60Gy, 150Gy, 300Gy, 450Gy and 600Gy @ 7.247KGyh-1 in the Floriculture Laboratory of National Botanical Research Institute (NBRI), Lucknow (India). The source for gamma ray irradiation was Cobalt-60. The irradiated seeds were sown in triplicates along with their respective controls. Results: Meiotic analysis of pollen mother cells (PMCs) at 300Gy showed translocation heterozygotes, however, in the control sets, the rate was negligible and phenotypically the plants were weak and short heighted. The cytological illustration of chromosomal configuration at diakinesis and metaphase I exhibited the superiority of tetravalents, bivalent and other forms of chromosomal associations such as multivalents. The induced translocation heterozygotes resulted in stickiness at metaphase and anaphase states along with the formation of bridges at anaphase stage. Due to chromosomal anomalies, the pollen fertility was reduced to 37.54±0.25% in contrast to control plants (98.20±0.16%). Interpretation: The current research work would be of paramount interest as translocation heterozygote serves as a source for raising aneuploid offspring having novel genetic combinations. Key words: Chromosomal anomalies, Heterozygotes, Lepidium sativum Linn, Meiosis, Pollen fertility

Assessing the sensitivity of maize genotypes to gamma radiation for germination and physiological characteristics

To meet the rising demand for cereal-based food products, it is essential to create parent lines for hybrid development. Evaluating the sensitivity of maize genotypes to gamma rays is critical for successful mass irradiation to induce mutations. This study aimed to assess how maize genotypes respond to gamma radiation and determine an effective dosage for mutation breeding. Six maize genotypes were subjected to gamma radiation doses ranging from 0 to 750 Gy (s) 60Co. The irradiated seeds were evaluated in controlled conditions and then planted in the field for the assessment of physio-agronomic traits. The lethal dose (LD50) was established based on the germination rate of the M1 generation. Results demonstrated a decrease in germination percentage, plant height, survival rate, root length, and plant photosynthetic rate with escalating gamma radiation doses. The mean LD50, determined from the germination data, was 254.3 Gy. The radiation dosage range of 206.71–301.95 Gy proved effective in influencing both quantitative and qualitative characteristics. These findings provide valuable insights into the efficient utilization of gamma radiation in expediting the development of promising parent lines, which can be instrumental in hybridization efforts to produce superior maize varieties.

Gamma irradiation of eggplant seeds influences plant growth, yield and nutritional profile in M1 generation

The study examines agromorphological traits and nutrient compositions in three genotypes of eggplants (Solanum melongena ‘African Beauty F1’ and ‘Melina F1’ and S. aethiopicum ‘Kotobi’) grown from seeds irradiated by gamma rays (γ-ray) with 100 Gy. Experiments were carried out in the screenhouse and experimental field of Crop Science Department, University of Calabar, Nigeria. Completely randomised design with four replications and randomised complete block design with three replications was used in the screenhouse and field experiments respectively. Eggplant × γ-ray effect reduced (p ≤ 0.05) seedling emergence, plant height and number of leaves in the nursery at 2 and 4 weeks after sowing. In the field, these traits were consistently lower for irradiated Melina F1 and Kotobi (p > 0.05) at ten weeks after transplanting. Irradiated African Beauty F1 had the highest (p ≤ 0.05) upper canopy leaf area (429.54 cm2), higher (p > 0.05) plant height and stem width; lower (p > 0.05) number of branches and leaves. Un-irradiated and irradiated Kotobi had the highest (p ≤ 0.05) fruit load, lower (p ≤ 0.05) fruit volume, weight and yields over four harvest intervals. Carbohydrate and energy contents of Kotobi fruits grown from 100 Gy gamma-ray irradiated seeds were concurrently improved (p ≤ 0.05). Gamma ray irradiation had both positive and negative influences on the agromorphological traits, mineral composition and nutrient profile of eggplants. However, 100 Gy dose of irradiation had a negative effect on fruit characteristics in general. From the results of this study, inconsistent variations in the agromorphological traits of the irradiated eggplants of the three varieties were reported. Therefore, the goal of mutation breeding in eggplant should not undermine the importance of the eggplant genotype as well as the actual radiation dose.

Profiles of Semi-Polar Metabolites from Leaves of In Vitro- Derived Plants of Indonesian Pepper Varieties (Capsicum annuum) after Gamma Irradiation Treatments

Gamma irradiation has been widely utilized for mutation breeding as it induces random mutations in plant cells. Due to limitations on other breeding approaches, including cross-breeding and transgenic plants, gamma irradiation-induced mutation breeding has regained its popularity among breeders and scientists. Untargeted metabolomics analysis can be used to profile any perturbation between untreated samples and treated sample groups without having prior knowledge of particular metabolites, including semi-polar metabolites, which cover phenolic acids, flavonoids, glycosylated steroids, alkaloids, and other glycosylated species. This study aimed to profile semi-polar metabolite modification in leaves of plants derived from in vitro cultures after gamma irradiation treatments in Indonesian chili pepper varieties. Seeds of Laris and Kopay were exposed to gamma-ray doses (0, 100, 200, 300, 400, and 500 Gy), after which they were germinated and cultivated in vitro. Plantlets were acclimated in the greenhouse and leaves were collected for metabolite analysis at 80 days after the germination of irradiated seeds. Semi-polar metabolites from leaves were extracted using methanol and the extracts were subjected to LC-MS analysis. Results showed that the composition and levels of semi-polar metabolites of Laris 100, 200, 300, 400, and 500 Gy were similar to Laris 0 Gy (control; unirradiated seeds), although several abundancies of that of 200 Gy gamma irradiation dose were different than control. Except at dose 400 Gy, Kopay at 0 Gy, 200 Gy, and 300 Gy also showed similar metabolite profiles, indicating that gamma-ray doses did not induce mutation at genes regulating metabolite biosynthetic pathways. In contrast, Kopay 400 Gy showed low levels of terpenoids and flavonoids, indicating that a 400 Gy dose of gamma ray may affect the upstream part of the shikimate biosynthetic pathway, resulting in low levels of precursors at the upstream biosynthetic pathway of terpenoids and flavonoids. Hence, the accumulation of terpenoids and flavonoids was very low. These findings provide insights into the effect of gamma irradiation for mutation breeding that may be important for future pepper breeding programs.

Bio-Stimulant for Improving Simmondsia chinensis Secondary Metabolite Production, as Well as Antimicrobial Activity and Wound Healing Abilities.

Simmondsia chinensis is a dioecious, long-lived perennial shrub. Its leaves contain several antioxidant flavonoids that have numerous pharmacological effects. Various strategies have been explored to propagate jojoba with enhanced pharmacological values. This research evaluates the bio-stimulatory impacts of He-Ne laser seed irradiation on seed germination, plantlet growth, and alteration of the composition and bioactivities of phytochemicals in jojoba plants. Jojoba seeds were irradiated for 5, 10, and 15 min before in vitro germination. Germination, growth, and multiplication parameters were recorded during germination, multiple-shoot induction, and rooting stages. The wound healing and antimicrobial activities of methanolic extracts from plant lines obtained from the non-irradiated (control) and 10 min irradiated seeds were compared by excision wound model in Wistar male rats and zone of inhibition assay. Our study revealed that laser irradiation increased seed germination, with the highest percentage observed in seeds irradiated for 10 min. Plant lines from the 10 min irradiated seeds produced more explants with higher explant heights and numbers of leaves, more roots, and higher photosynthetic pigment contents than those of control and other laser testings. By comparing plant extracts from the control and 10 min treatments, we observed that extracts from the 10 min treatment exhibited higher percentages of wound contraction and shorter epithelialization periods. In addition, these extracts also resulted in higher levels of angiogenesis elements (VEGF, TGF-β1, and HIF-1α) and reduced the inflammation regulators (IL-1β, IL-6, TNF-α, and NFκB) in the experimental rats. In concordance, extracts from the 10 min treatment also explained raised antibacterial activities towards Staphylococcus aureus and Escherichia coli. Our findings show that pre-sowing seed treatment with a He-Ne laser (632.8 nm) could be a good technique for stimulating S. chinensis plant growth and increasing the impact compound levels and biological activities.

Genetic variability of mutant rice (Oryza sativa) genotype induced by gamma rays

Abstract. Ishak I. 2023. Genetic variability of mutant rice (Oryza sativa) genotype induced by gamma rays. Biodiversitas 24: 3300-3306. Rice seeds of Sidenuk cultivars were irradiated by gamma rays creating a broad spectrum of genetic variability among individual plants at M3 generation progeny. Gamma Irradiated seeds created Mutation among the somatic cells population in mature embryos at M1 generations. Somatic cell mutation influenced the genetic structures of gametes cells formation on gametogenesis at M1 plants. Observation of M2 plants showed that black and brown colors of rice's pericarp were found with rice's lemma, and palea color was different compared to the wild type (Sidenuk cultivars). Seven plants with black rice pericarp colors out of 330 were obtained at M2 plants. Chlorophyll mutation was observed at M4 generation; the results showed that chimera, green, and albino leaf blade was obtained in several individual plants. There were also the variability of Palea and lemma colors among individual plant such as green, white, and purple. The cellular biology approach will explain these mutations before molecular biology identification is made.

Effects of ionizing radiation on radio sensitivity of cell nuclei of wheat seedlings

Effects of the 50 Gy and 100 Gy doses of Y-irradiation on radiosensitivity of cell nuclei of soft dwarf wheat seedlings were studied. Changes in the biochemical composition of the nuclear fractions of seedlings of wheat seeds exposed to gamma-irradiation were determined. After exposure to ionizing radiation, total protein and nucleic acids levels appeared to be greater in the soluble nuclear fraction and the nuclear membrane-associated DNA content and proteins increased. It was also found that the value of the dzeta-potential of isolated nuclei of seedlings of irradiated seeds decreased in a static electric field. Changes in the surface charge of the nucleus lead to a violation of its functional activity, since the surface charge of the nuclei is necessary for the normal functioning and regulation of the nuclear-cytoplasmic transport of macromolecules. Exposure to radiation causes destruction of ionogenic groups of molecules of the nuclear membrane, leading to a decrease in the electronegativity of the nuclei, which, in turn, entails a change in the functional activity of the nucleus. The results obtained show that changes in electronegativity and in the content of nuclear fractions are directly dependent on the dose of ionizing radiation. It can be concluded that Y-irradiation in a range from 50 to 100 Gy had beneficial effects on metabolic and proliferative activities of soft wheat cells.

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.

Evaluation of morpho-physiological responses and genotoxicity in Eruca sativa (Mill.) grown in hydroponics from seeds exposed to X-rays.

Due to its potential applications in cultivated plants, ionizing radiation (IR) and its effect on organisms is increasingly studied. Here we measured the effects of ionizing radiation on Eruca sativa by analyzing plants from irradiated seeds (1 and 10 Gy) grown in hydroponics. We measured several morpho-physiological traits and genotoxicity. Radiation stress induced a noticeable variability of the morpho-physiological traits highlighting decreased plant vigor. Shoot length and leaf number were significantly higher in 1 Gy-treated samples, whereas root length was significantly higher in 10 Gy treated plants. Stomata number significantly increased with IR dose, whereas both pigment and Rubisco content decreased under radiation stress. Phenol content significantly increased in 1 Gy treated samples, otherwise from total antioxidants, which were not different from control. Most results could find a feasible explanation in a hormesis-like pattern and in a decreased plant vigor under radiation stress. IR induced genotoxic damage, evaluated by ISSR markers, in 15 day old leaves; specifically, a severe decrease in the genome template stability was observed. However, a partial recovery occurred after 2 weeks, especially under the lowest dose (i.e., 1 Gy), suggesting that DNA damage detection and repair mechanisms are active. Pigment content and genotoxic damage may serve as proxies for evaluating plant responses to IR stress, since they show univocal dose-dependent trends. The use of more checkpoints for analyses and more doses over a wider range, as well as the focus on different metabolites, could help elucidate plant response in terms of morpho-physiological changes.

Impacts of Gama Irradiations on the Development New Mutants of Stevia rebaudiana Bertoni

Stevia rebaudiana Bertoni is known for its production of sweet glycosides, an alternative to sugar. The cultivation of stevia in Malaysia is hampered because- it produces flowers at an early stage under Malaysia's photoperiod condition, thus leading to poor leaf yield for sweetener extraction. Additionally, there has been low breeding work for suitable cultivars. Thus, the impact of Gama irradiation in developing new Stevia mutants was studied. Seeds of MS012 were collected and exposed to gamma irradiation using a gamma cell in UKM, Malaysia to determine the LD50. The seeds were packed into 21 parts; one part served as the control and the others were subjected to varying gamma irradiation grays of 100 to 2000 grays. Irradiated seeds were sown for germination under the red light for 15 days. The LD50 was determined by plotting a simple regression graph of plant height against irradiation grays. Results revealed LD50 was 55 grays. The number of germinated seeds differed with respect to doses. Genetic analysis showed four types of chlorophyll mutants were induced: Albina, Chlorina, Xantha and Xantha-Viridis. Frequency and spectrum analysis revealed that Chlorina has the highest occurrence at 33.03%. Two classical novelties: (i) M1RAAMBO/03, and (ii) M2 RAAMBO/04 were developed.