Irradiated Seeds Research Articles

The Effect of Ionizing Radiation on Vernalization, Growth and Development of Winter Wheat

The effects of gamma irradiation on the vernalization requirements, growth and development of winter wheat grown in a rainout shelter were studied during two successive growing seasons. Dry grains of winter wheat cv. Kobra were irradiated with 300 Gy radiation from a cobalt 60 gamma irradiator. Treated and control grains were pregerminated and subjected to vernalization for 0, 42 or 54 days. Morphological parameters of the plants developing from irradiated seeds (M1 generation) and the plants grown from the seeds produced by the irradiated plants (M2 generation) were measured in order to track the studied effects over two generations. Irradiation of dry grains slowed the growth and development of the plants regardless of the temperature treatment. The measured yield structure elements appeared to be lower for irradiated plants, but no clear effect of radiation on vernalization requirements was noted.

IV. Effect of <sup>60</sup>Co gamma rays on survival rate of China aster plants (Callistephus chinensis Nees) in M1 generations - under field conditions

Studies were undertaken on the effect of different doses of gamma radiation on survival rate of plants (germinated from irradiated seeds) for 5 China aster varieties specified at florescence time. During their growth under field conditions (from planting time to blooming) lethal effect of the radiation occurred in plants of all varieties and its level depended on dose and variety. Effect of 3 kR and 6 kR doses differed depending on variety and was not always harmful, but following irradiation with doses exceeding 6 kR a considerable decrease in survival rate was observed. Radioresistance of studied varieties - measured both: by LD<sub>50</sub> and LD<sub>l00</sub> - differed; depending on variety, LD<sub>50 </sub>and LD<sub>l00</sub> values fluctuated: from 6 to 9 kR and 12 to 15 kR respectively.

Yağ Gülü (Rosa damascena Mill)'nde Mutasyon Islahı

Mutation breeding is one of the ways to create genetic variation of oil rose, as in other species. In the present study, it is aimed to develop superior mutants in terms of mophological, agronomic and quality characteristic compare to the oil rose. Oil rose fruits (Rosa damascena Mill.) were harvested and seeds were extracted in 2007. 1000 seeds were irradiated with 0, 100, 200, 300, 400 Gry doses of the cobalt 60 gamma-ray in Atomic Energy Agency, Ankara, Turkey. Irradiated seeds were stratified at 4oC for 3 month and planted to viols on March in 2008. Seedlings applied 0, 100, 200 Gry doses were transferred to pots in 2008 and were planted to field on March in 2010. Mutant oil roses showed wide genetic variation for flower color (from darker pink to white), petal number (from 5 to 90) and flowering period (M1 generation) in 2011

III. The effect of various doses of gamma 6OCo radiation upon pollen vitality of China aster (Callistephus chinensis Nees) in M1 and M2 generation

The effect of gamma radiation upon pollen was studied in populations of 4 China aster varieties in M<sub>1</sub> (plants from irradiated seeds) and M<sub>2</sub> generation. Effect of radiation Was assessed·in partiicular years. Comparison was rnalde between pollen vitality in irradiated plants and in the control. Effect of radiation was visibly harmful only in case of plants from M<sub>1</sub> generation. The effects of radiation were different for particular varieties.

Laser treatment may enhance growth and resistance to fungal infection of hard wheat seeds

The effect of Hard wheat (Triticum durum ) seeds exposer to visible light with = 632nm, 650nm and 532nm produced from He-Ne ,Diode and SHG Nd-YAG lasers respectively on germination , early growth and resistance to fungal infections had been studied under laboratory conditions. He-Ne & diode laser enhanced the germination percentage of wheat cultivars after two days a maximum of 95% & 93% after irradiation respectively for 5 minutes in respect to control, with the beginning to infection with fungus in both irradiated and non irradiated seeds, SHG Nd-YAG laser significantly enhanced the germination percentage of wheat after 3 days to reach maximum of 93% after irradiation .Seeds irradiated with SHG Nd-YAG laser ,no fungi infection was recorded ,while seeds irradiated by the two other types show highly infection especially after 3 days ,and the petri plates which added to them antifungal agent show significant increase in infection with and without irradiation. From these results, we concluded that SHG Nd-YAG laser Irradiation could be an alternative method to control seed infection by fungi of hard wheat seeds.

II. The effect of various doses of gamma 60Co radiation upon some morphological features of China aster (Callistephus chinesis Nees) in M1 and M2 generations

The present paper discusses the effect of antecedent gamma radiation upon 4 varieties of China aster in M<sub>1</sub> and M<sub>2</sub> generations. Studies were undertaken on the effect of various doses of radiation upon the following features : height of plants, maximal length of ramification of the Ist order, diameter of inflorescence, and number of set inflorescence. In M<sub>1</sub> generation (plants from irradiated seeds) negative effect of radiation was noted in almost all features under study, usually the greater the radiation dose. Only in case of two varieties ('Agnieszka' and 'Goplana') positive effect of irradiation upon plant height was noted, at radiation dose of 3 kR. However, further increase of radiation dose was harmful also for these two varieties. In M<sub>2</sub> generation (progeny of irradiated plants) the effect of gamma radiation upon most features under study was beneficial - in most cases stimulation overbalanced rare symptoms of depression. Reaction was different in all varieties under study.

Biomass and Molecular Characteristics of Multi-tillering Miscanthus Mutants

Compared to wide ranges of genetic variation of natural populations, very limited Miscanthus cultivar has been released. This study was the first report on the development of Miscanthus cultivar by means of radiation breeding. Seeds of M. sinensis were initially exposed to gamma rays of 250 Gy for 24 h, generated from a <TEX>$^{60}Co$</TEX> gamma-irradiator. The irradiated seeds were sown and then the highly tiller-producing mutants were selected for this study. Biomass-related parameters including tiller number, plant height, stem diameter, and leaf number were measured. Ploidy level and internal transcribed spacer (ITS) were investigated to characterize the mutants compared to wild type (WT) Miscanthus. Plant height and tiller number were negatively related, where multi-tillering mutants were relatively short after 4 month growth. However stem diameter and leaf number were greater in mutants. All the materials used in this study were diploid, implying that the mutants with greater tiller numbers and stem diameter were not likely related to polyploidization. Based on the sequence of ITS regions, the mutants demonstrated base changes from the gamma irradiation where G+C content (%) was decreased in the ITS1, but increased in ITS2 when compared to WT sequence. ITS2 region was more variable than in ITS1 in the mutants, which collectively allows identification of the mutants from WT. Those mutants having enhanced tillers and allelic variations might be used as breeding materials for enhanced biomass-producing Miscanthus cultivars.

Anti-oxidant modulation in response to gamma radiation induced oxidative stress in developing seedlings of Psoralea corylifolia L.

The seeds of Psoralea corylifolia L., an important medicinal herb in Indian and Chinese Pharmacopeia were exposed to gamma rays (2.5, 5, 10, 15 and 20 kGy) from Co60 source at dose rate of 1.65 kGy h−1. Enzymatic and non-enzymatic anti-oxidant responses were verified according to the developmental stages and gamma dose applied. Plants grown from seeds exposed to higher gamma doses exhibit higher activity of the antioxidants such as [Ascorbate peroxidase (APX, 1.11.1.1), superoxide dismutase (SOD, 1.15.1.1), glutathione reductase (GR, 1.6.4.2) and MDA content till flowering and declined thereafter. In contrast, CAT (1.11.1.6) activity declined in dose and age dependent manner. The correlation of gamma dose applied and oxidative stress was inferred from the increased enzymes activities and depression in total glutathione pool in seedlings developed from irradiated seeds. Nevertheless, the maintenance of high anti-oxidant capacity, psoralen accumulation seems to be an important strategy during acclimation of P. corylifolia to gamma radiation stress. Pronounced accumulation of psoralen following 15 and 20 kGy at post-flowering stage where oxidative stress is triggered modulates lipid peroxidation and proline accumulation. Further, in psoralen producing plants an increase in psoralen content can be used as a biomarker which specifies plant is under stress.

Influence of Helium‐Neon Laser Irradiation on Seed Germination In Vitro and Physico‐Biochemical Characters in Seedlings of Brinjal (Solanum melongena L.) var. Mattu Gulla

In the present study, the seeds of brinjal (Solanum melongena L.) var. Mattu Gulla were irradiated with single exposure of He-Ne laser at different doses of 5-40 J cm(-2) and germinated aseptically. Thirty day old seedlings were harvested and the germination, growth, physiological and biochemical parameters were estimated and compared with un-irradiated control seedlings. A significant enhancement in growth characters were noted with respect to length, fresh and dry weight of shoots and roots. In addition, chlorophyll (a and b), carotenoid content, anthocyanin and amylases (α and β) activities were found to be altered. Significant alterations in percentage of seed germination (P < 0.001) and time to 50% germination (P < 0.001) were observed in the irradiated seeds compared with the un-irradiated controls. In conclusion, the results of the present study demonstrated that low dose (5-30 J cm(-2) ) of He-Ne laser irradiation enhanced the germination process and altered growth, by positively influencing physiological and biochemical parameters of the brinjal seedlings compared with un-irradiated control under in vitro conditions.

The Effect of r-irradiation and Cooking on the Physicochemical Properties of African Oil Bean Seed (Pentaclethra macrophylla benth) and Its Oil Extract

Irradiation is a potentially useful technology for ensuring the safety and extending the shelf-life of food products. The effects of r-irradiation (5kGy, 10kGy), cooking and combined treatment of 10 kGy irradiation and cooking on the chemical and functional properties of African oil bean seed (Pentaclethra macrophylla Benth) and physicochemical properties of its oil were investigated. The irradiated seeds and un-irradiated seeds were mechanically dehulled and milled into flour using an attrition mill. ‘Raw seed’, ‘cooked seed’, ‘irradiated (5kGy) seed’, ‘irradiated (10kGy) seed’ and ‘irradiated (10kGy) and cooked seed’ flour samples were analyzed for proximate composition, mineral content, functional properties and antinutritional factors, and the seed oils were analyzed for peroxide value, iodine value, acid value and free fatty acid content. The results show that the combined effect of r-irradiation and cooking gave highest increase in nutritional quality, reducing protein from 32.91g/100g DM in the raw seed to 30.55g/100g DM and increasing fat content from 47.43g/100g DM to 51.19g/100g DM. Combined treatment led to the retention of sodium, calcium, zinc and iron more than the single treatments, but the same process reduced magnesium from 0.52mg/100g to 0.47mg/100g and phosphorus from 0.43mg/100g to 0.35 mg/100g. Least gelation concentration and emulsion capacity increased with combined r-irradiation and cooking, whereas foaming capacity and water absorption capacity decreased significantly (p<0.05). Gamma-irradiation and cooking reduced the concentration of all the antinutritional factors. Combined r-irradiation and cooking increased the peroxide value significantly (p<0.05) from 7.03 mg/g oil to 16.50 mg/g oil and increased the acid value, iodine value and free fatty acid of P. macrophylla seed oil. Combination of r-irradiation and cooking increased nutrient bioavailability in the seed; it led to improvement in the functional properties and increased the susceptibility of the oil to rancidity.

Effect of laser light treatment on some biochemical and physiological processes in seeds and seedlings of white lupine and faba bean

The aim of present study was to determine the changes of some biochemical and physiological processes, which occurred in seeds and seedlings of white lupine and faba bean after pre-sowing treatment with laser beams. It was found this treatment of seeds considerably increased the activity of amylolytic enzymes in seeds of both plants. The greatest differentiation of the enzymatic activity was noticed after 120 h from the time of sowing but the activity of these enzymes in the seeds of both tested plants was similar and it had the same course in time. The irradiated seeds of white lupine and faba bean had higher fresh weight at the time of imbibition than the seeds which were not treated with laser beams. It resulted in earlier and more uniform germination. The concentration of free radicals increased considerably in the seeds pre-treated with laser beams and the largest increase in seeds of both plant species was noticed after five exposures to laser beams. Treating seeds with laser beams considerably increased the amount of indole-3-acetic acid (IAA) in the germinating seeds. Three exposures of seeds caused the largest increase of this plant hormone content in the seeds. The activity of IAA in faba bean was slightly higher than in white lupine seeds. Pre-sowing stimulation with laser had a positive influence on the growth and development of seedlings, which had longer hypocotyl and roots in comparison to seedlings which grew from non irradiated seeds.

Effect of Gamma Rays on Seed Germination, Seedling Height, Survival Percentage and Tiller Production in Some Rice Varieties Cultivated in Sierra Leone

Thirteen rice varieties cultivated in Sierra Leone were used to examine varietal differences in radiosensitivity to gamma radiation during the wet season of 2006 in the lowland ecology. Dry seeds of rice varieties were exposed to gamma radiation ranging from 50 to 800 Gy to determine their responses to radiation and the effective radiation dose for mutation breeding. Percentage germination, percentage survival (field condition), seedling height and tiller production were the traits measured on the M 1 generation. The results indicated that increasing doses of gamma irradiation had no effect on germination for the first seven days under laboratory conditions. Percentage survival of germinated seedlings from the 8 th to 14 th day under laboratory conditions decreased significantly with increase in radiation dose up to 600 Gy. With increase in radiation above 300 Gy a reduction in seedling height and percentage survival under field conditions was observed in irradiated plants of M 1 generation. Increase in gamma ray doses from 50 to 300 Gy had little or no effect on tiller production as there were no significant differences in tiller number of irradiated seeds and non-irradiated (control) for all the varieties evaluated. The LD 50 values determined from regression analysis based on percentage field survival ranged from 345 Gy for ROK18 to 423 Gy for ROK22. These ranges of LD 50 values determined for the different rice varieties could be useful in rice varietal improvement programmes in Sierra Leone.

EVALUATION OF GROWTH PARAMETERS AND SPECTROSCOPIC INDEXES OF CANOLA FROM SEEDS SUBJECTED TO NON- IONIZING RADIATION STRESS

This study reports the effect of UV-VIS rays on the spectroscopic indexes and the growth parameters of canola cotyledon. Canola seeds were exposed to incoherent continuously radiation with wavelengths between 300 and 750 nm emitted by a high pressure lamp, for different exposure times. An untreated sample is used for comparison purposes. Seed germination and allometric scaling were related to irradiance treatments. The unsaturation and carbonyl spectroscopic indexes changes in the canola cotyledon stems from irradiated seeds were evaluated by Fourier Transform Infrared FTIR spectrophotometric methods. FTIR spectra suggest that the processes of irradiation do not affect the chemical fingerprints (ca. 900 1200 cm-1) and had no significant effect (p > 0.05) to the molecular spectrum in lipid related functional groups. On the other side, the results of non parametric Kruskal-Wallis Test confirm that all investigated samples are independent. The main significant effect was obtained at root level to the sample irradiated for 160 minutes (.2 = 11.358, df = 3, p =0.010). The growth of the organ parts was characterized by a negative allometric factor for control, 280 minutes and 460 minutes irradiated samples. However, for 160 minutes irradiation time, an isometric scaling (a =1.013) was obtained. The results show that 177 kJ/m2 ultraviolet dose was not strong enough to induce changes in lipid conformation. Significant changes in terms of growth parameters of canola cotyledon can be observed mainly caused by continuously emission lines at 365 nm, 436 nm and 620 nm. In the cases of irradiated seeds the proportion of germinating seeds decreased compared with the control sample. The largest decrease occurs at 160 minutes irradiation time. In this case a strong absorption of the orange radiation on 620 nm is probable. It may be assumed that the canola seeds are negatively photoblastic, in most cases. This study will prospectively justify the response investigation of molecular structure and growth parameters to various external stresses induced on the canola seeds differentiated by the age of plant and by selected wavelengths.

Effect of Gamma Irradiation on Morpho-Agronomic Characteristics of Soybeans (&amp;lt;i&amp;gt;Glycine max&amp;lt;/i&amp;gt; L.)

Mutation breeding in crop plants is an effective approach in improvement of crop having narrow genetic base such as soybean. The main objective of the present study is to determine the effect of different doses of gamma irradiation on different morpho-agronomic characteristics. Agronomic traits that were analyzed included; grain yield, number of pods/plant, number of seeds/plant and weight of 100 seeds and numbers of days to 50% flowering. Morphometric characterization of the descriptive data included plant height, stem diameter, number of leaves/plant, leaflet length, leaflet width, number of ramifications/plant, and pod length and width at 3 lodge stage. The results of the present study revealed that the two gamma irradiation doses used (0.2 kGy and 0.4 kGy) decreased significantly most of agronomic and morphological traits evaluated in M1 populations. Different effects of 0.2 kGy and 0.4 kGy irradiation were observed in M2 populations with significant increase of grain yields and yield components in all the three soybean varieties. In general, a significant decrease or no changes of morphological traits were observed for the two irradiation doses in M2 populations. The levels of changes varied among varieties. Potential high yielding mutants were identified in progenies of irradiated seeds.

Effect of gamma irradiations on seed germination and seedling survival of Stevia rebaudiana Bert.

Stevia rebaudiana  Stevia rebaudiana  Stevia started simultaneously 7 days after sowing. Differencesin the germination and survival percent were recorded in the first generation.High dose of Gamma irradiation increased delay in days of germinationand maturity. The germination and survival percent decreased with increasingdosage of gamma radiations. The data on days to germination, germinationpercentage and survival percentage, indicated that low dose ofgamma radiation had very less effect on germination of Stevia seeds. It wasnoticed that up to 5 to 10 KR dose there was no statistically significant differencein seed germination as compared to control. However, germinationpercentage was significantly affected by higher doses of gamma rays.seeds. The seeds were given 5, 10, 15, 20, 25 and 30 KR(Kiloradians) exposures. Gamma irradiated seeds were treated with sodiumazide and colchicines solution for 4 h separately. Germination in control andtreated seeds of Bert. produces sweet steviol glycosides in the leaves. Currentinvestigation was carried out to study effects of gamma irradiations on

Together yes, but not coupled: new insights into the roles of RAD51 and DMC1 in plant meiotic recombination

The eukaryotic recombinases RAD51 and DMC1 are essential for DNA strand-exchange between homologous chromosomes during meiosis. RAD51 is also expressed during mitosis, and mediates homologous recombination (HR) between sister chromatids. It has been suggested that DMC1 might be involved in the switch from intersister chromatid recombination in somatic cells to interhomolog meiotic recombination. At meiosis, the Arabidopsis Atrad51 null mutant fails to synapse and has extensive chromosome fragmentation. The Atdmc1 null mutant is also asynaptic, but in this case chromosome fragmentation is absent. Thus in plants, AtDMC1 appears to be indispensable for interhomolog homologous recombination, whereas AtRAD51 seems to be more involved in intersister recombination. In this work, we have studied a new AtRAD51 knock-down mutant, Atrad51-2, which expresses only a small quantity of RAD51 protein. Atrad51-2 mutant plants are sterile and hypersensitive to DNA double-strand break induction, but their vegetative development is apparently normal. The meiotic phenotype of the mutant consists of partial synapsis, an elevated frequency of univalents, a low incidence of chromosome fragmentation and multivalent chromosome associations. Surprisingly, non-homologous chromosomes are involved in 51% of bivalents. The depletion of AtDMC1 in the Atrad51-2 background results in the loss of bivalents and in an increase of chromosome fragmentation. Our results suggest that a critical level of AtRAD51 is required to ensure the fidelity of HR during interchromosomal exchanges. Assuming the existence of asymmetrical DNA strand invasion during the initial steps of recombination, we have developed a working model in which the initial step of strand invasion is mediated by AtDMC1, with AtRAD51 required to check the fidelity of this process.

A combined methodology to detect γ-irradiated white sesame seeds and evaluate the effects on fat content, physicochemical properties and protein allergenicity

White sesame seeds (Sesamum indicum L.) were studied with the purpose to evaluate γ-irradiation effect at 2.5, 5.0 and 10.0kGy on lipid and fatty acid content, colour and protein allergenicity and to identify whether sesame oil was extracted from irradiated seeds by using High Resolution Nuclear Magnetic Resonance spectroscopy (HR-NMR). The fat decreased significantly, whereas triglyceride and phospholipid content was significantly decreased by the increase of irradiation dose. Monounsaturated and polyunsaturated fatty acids and unsaturated/saturated fatty acids ratio decreased. The presence of radiolytic decomposition products, shown by NMR, formed after a 2.5kGy dose, confirmed that the lipid content decrease was a result of the irradiation process. The allergenicity of storage seed proteins was not significantly affected by irradiation up to 10.0kGy. Colour parameter a* increased after 5.0kGy, while L* values decreased significantly after 2.5kGy. Conclusively, irradiation could be applied at doses <2.5kGy while sustaining the sesame seed nutritional benefits.

Chickpea response to low doses of gamma radiation

The effect of low doses (0, 5, 10, 15, 20 and 25 Gy) of gamma rays from radioactive cobalt on chickpea plant growth, protein content of leaves and grains harvested from irradiated seeds grown in pots indicated that 20 Gy enhanced plant growth by 146.35% compared to plants grown from non irradiated seeds. Root nodules number was also 260.80% higher under 20 Gy level of irradiation compared to plants developed from non irradiated seeds. The 20 Gy dose also improved nodule weight by 300%, protein content of the leaves and grains by 189.81 and 93.16%, respectively.

Effect of gamma irradiation on physicochemical properties, proximate composition, vitamins and antinutritional factors of the tribal pulse Vigna unguiculata subsp. unguiculata

SummaryEffect of gamma irradiation on Vigna unguiculata subsp. unguiculata seeds (maroon‐coloured seed coat) at various doses (2, 5, 10, 15 and 25 kGy) on the physicochemical properties, proximate composition, vitamins (niacin and ascorbic acid) and antinutritional factors were analysed. No significant changes were recorded in the physicochemical properties of irradiated seeds. Gamma irradiation resulted in a significant increase in crude protein, while the crude lipid, crude fibre and ash contents resulted in a dose‐dependent decrease. Gamma‐irradiated seeds presented a significant decrease in the ascorbic acid and niacin content. Irradiation processing significantly reduced the level of L‐DOPA, phytic acid, hydrogen cyanide, trypsin inhibitor activity, oligosaccharides and lectins. The total free phenolics, tannins and in vitro protein digestibility on irradiation showed a significant dose‐dependent increase. Gamma irradiation seems to be a good procedure to improve the quality of legume seeds from the nutritional point of view.

A fresh method of DNA transformation to the seeds irradiated by 60Co without the use of antibiotic selection

To find out a simpler method that can directly transfer the aim gene into plant genomes, the purple medic seeds irradiated by 60 Co with 0.375 Gy were transformed by linear DNA containing a β-glucuronidase (GUS) gene (as an aim gene), a betaine aldehyde dehydrogenase (BADH) gene (as a selectable marker) and two pairs of both CaMV35S promoter and Nos terminator. Subsequently, the seeds were planted and grown in perlite media watered with NaCl solution as a kind of selective compound. The results showed that, positive frequency of PCR identification by the GUS gene or the BADH gene was higher than 53.2 and 89.5% in T 0 and T 1 generations, while GUS staining rate was higher than 50%; whereas five T 1 plants assayed by southern hybridization all showed positive reaction. In conclusion, by this method, transgenic plants may be easily obtained with the antibiotic markers for free; moreover, the plant regeneration-system must not be erected by directly transforming the seeds. Key words : DNA transformation, irradiated seeds, purple medic, salt screening.