scholarly journals Effects of Co 60 Gamma Irradiation on Corn Pollen

1969 ◽  
Vol 50 (1) ◽  
pp. 10-17
Author(s):  
Vicente Rodríguez ◽  
D. B. Linden

Corn tassels were irradiated using Co 60 gamma rays at dose levels from 250 to 20,000 r. Twenty-four and forty-eight hours after irradiation the pollen was collected from the tassels and used to fertilize ears. The quantity of good seeds per ear, the germination percentage of these good seeds, and the seedling height 7 and 14 days later of the plants from these germinated seeds were recorded. No seeds were obtained beyond 4,000 r. There was little effect from pollen used 24 hours after treatment compared ivith pollen used 48 hours after treatment for any of the characters measured. There was a general dose response for number of good seeds per ear, and also in the percentage of germination of those seeds classified as good. The higher doses reduced both numbers of good seeds and their germination. There was no evident dose response of seedling height, if the seed did germinate it grew about as well as any at the dose levels measured.

2010 ◽  
pp. 23-25
Author(s):  
Delia Marcu ◽  
Constantin Cosma

In order to study the effects of gamma rays on germination indices i.e. germination index (GI), total germination (GT) and thegermination energy (GE), of maize hybrid, Turda Star current experiment was conducted. Dry seeds of Turda Star maize hybrid wereirradiated with 2, 5, 15, 30 and 50 Gy, using a 60Co-gamma radiation source.Results showed that gamma irradiation affected all the above mentioned parameters except germination percentage. Totalgermination and germination energy was significantly affected at higher doses of gamma rays. However, increasing doses of gammarays did not have significant effects on seed germination percentage. The other growth parameters showed declining tendency withincreasing doses of gamma irradiation.


2012 ◽  
Vol 41 (1) ◽  
pp. 1-5 ◽  
Author(s):  
MMA Albokari ◽  
SM Alzahrani ◽  
AS Alsalman

Seeds of four local wheat (Triticum aestivum L.) cultivars, namely Hinta, Khaliji, Lokaimy and Qasime collected from different regions of Saudi Arabia were exposed to different doses of gamma rays 50-500 Gy to determine suitable doses for induction of mutation. It was observed that seedling height decreased with the increased dose of radiation in all cultivars. Radiosensitive curve originated from seedling height data resulted in 179, 225, 249 and 256 Gys as LD50 values for the cultivars Hinta, Khaliji, Qasime and Lokaimy, respectively. Based on LD50, as to minimize DNA damage and reduce undesirable mutations, radiation doses which lie between 200 and 250 Gy can be considered suitable for induction of mutation in cultivars Lokaimy, Khaliji and Qasime while between 150 and 200 Gy for cultivar Hinta DOI: http://dx.doi.org/10.3329/bjb.v41i1.11075 Bangladesh J. Bot. 41(1): 1-5, 2012 (June)


1963 ◽  
Vol 42 (2_Suppl) ◽  
pp. S17-S30
Author(s):  
Fred A. Kind ◽  
Ralph I. Dorfman

ABSTRACT Thirty-seven steroids have been studied as orally effective inhibitors of ovulation in the mated oestrus rabbit. Norethisterone served as the reference standard and a dose response curve was established between the 0.31 and 1.25 mg dose levels. Nine highly active anti-ovulatory compounds are described listed in a decreasing order of potency with norethisterone having the arbitrary value of one: 6-chloro-Δ6-dehydro-17α-acetoxyprogesterone (35), 6α-methyl-Δ1-dehydro-17α-acetoxyprogesterone (≥ 10), 6-fluoro-Δ6-dehydro-17α-acetoxyprogesterone(9), 6-methyl-Δ6-dehydro-17α-acetoxyprogesterone (5), Δ6-dehydro-17α-acetoxyprogesterone (≥ 3), 6α-methyl-17α-acetoxyprogesterone (2.6), 6-chloro-Δ1,6-bisdehydro-17α-acetoxyprogesterone (≥ 2), 2-hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one (≥ 2), and 6α-fluoro-16α-methyl-17α-acetoxyprogesterone (≥ 1.25). The anti-ovulatory activity of a compound was not related necessarily to the progestational activity of a compound nor to the anti-gonadotrophic activity as measured in parabiotic rats. 6-Chloro-Δ60dehydro-17-acetoxyprogesterone was as effective by gavage as previously shown by subcutaneous injection. 2-Hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one was at least 2.5 times more active by gavage than by injection. While 17α-acetoxyprogesterone was a very weak anti-ovulatory steroid, modifications of the structure by addition of methyl or halogen at the 6α position with or without unsaturation greatly increased the activity. 6-Chloro-Δ6-dehydro-27α-acetoxyprogesterone was the most active compound in this series showing a relative potency of 3500 times that of the parent compound 17α-acetoxyprogesterone.


1970 ◽  
Vol 64 (2) ◽  
pp. 265-272 ◽  
Author(s):  
A. A. van der Gugten ◽  
M. Sala ◽  
H. G. Kwa

ABSTRACT Eight female and eight male rats were castrated at the age of 8 to 10 weeks. Four spayed and four orchidectomized rats received one oestrone/cholesterol pellet (200 μg oestrone) on the day of operation (day 0), a second pellet on day 11 and a third on day 23. The remaining animals received four oestrone/cholesterol pellets at these times. The fluctuations in the prolactin levels in the circulation induced by the oestrogen challenges in these animals were followed during 31 days by radioimmunoassays performed on days 3, 7, 9, 14, 15, 17, 23, 24, 25, 28 and 31. The results suggested that the homoeostatic mechanism regulating plasma levels of prolactin was capable of withstanding the three time-spaced oestrogen challenges only in the spayed animals receiving the lower doses of oestrogen, since it allowed the mean values of the prolactin levels to remain fairly constant during the first 4 weeks. The levels in this group rose to much higher levels only on day 31. The higher doses of oestrone in the spayed rats and both dose levels of oestrone in the orchidectomized animals apparently resulted in a primary break-down of the homoeostatic mechanism, since the prolactin levels in the animals of these groups rose to much higher levels either on day 7 or on day 9. This was followed by a period during which the prolactin levels appeared to be more or less under control, until a second and probably definitive failure of the homoeostatic mechanism allowed the mean levels to rise sharply again.


2017 ◽  
Vol 4 (04) ◽  
Author(s):  
ANURADHA PATEL ◽  
POONAM VERMA ◽  
SHARDA CHOUDHARY ◽  
ARVIND KUMAR VERMA

Fenugreek (Trigonella foenum-graecumL.) is an annual crop, mainly used as a spiceand leafy vegetable crop in many parts of the world. Classical breeding in fenugreek is restricted due to its low genetic variability and small flower size which hamper manual emasculation and pollination. Mutation breeding is an effective way to enrich genetic variability in crop plants. An experiment was conducted to determine the lethal dose of the physical mutagen gamma rays in fenugreek. The dry seeds of fenugreek were exposed to different doses of gamma rays i.e. 150Gy, 200Gy, 250Gy, 300Gy and 350Gy. These irradiated seeds were sown in the Petri plates with non-irradiated seeds (control). As the dose of gamma rays increased, there was a decrease in germination percentage, seedling survival, root length, shoot length and vigour index. Among five doses of gamma rays, the maximum seed germination was observed at lowest dose 150Gy (93%), followed by 200Gy (83%), 250Gy (76%), 300Gy (76%) and 350Gy (64%). The seedling survival was decreased from 90% (in control) to 56% in 350Gy dose of gamma rays. The gamma rays dose of 150Gy gave stimulatory effect on seedlings growth. The growth parameters were dose dependent, as the dose of gamma rays increased from 200Gy to 350Gy. The gamma rays dose of 350Gy showed 64% seeds germination and 56% of seedlings survival. Therefore, it is concluded that the LD50 dose for fenugreek is close to 350Gy. This information would be highly useful for initiating mutation breeding programme in fenugreek


2012 ◽  
Vol 5 (1) ◽  
pp. 25-31 ◽  
Author(s):  
M. S. Rahman ◽  
J. I. Lee ◽  
J. L. Kim ◽  
G. Cho

The dosimetric properties of the newly developed thermoluminescence (TL) material (LiF:Mg,Cu,Si) at Korea Atomic Energy Research Institute (KAERI) were investigated. The energy response of the detector was performed for photon energies from 20 to 662 keV. The dose response for this TL material (LiF:Mg,Cu,Si) was linear up to 10 Gy and a sub-linear response was observed for higher doses. The reusability of this newly developed TL detector sufficiently satisfied IEC standards. Detection threshold of LiF:Mg,Cu,Si TL material was investigated and found to be 930 nGy by Harshaw 4500 TLD reader. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.11935        J. Sci. Res. 5 (1), 25-31  (2013) 


2014 ◽  
Vol 39 (3) ◽  
pp. 124
Author(s):  
Y. Lusiyanti ◽  
Z. Alatas ◽  
M. Lubis ◽  
V.A. Suvifan ◽  
D. Ramadhani ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1638
Author(s):  
Seong-Min Kim ◽  
Yeong Deuk Jo ◽  
Jae-In Chun ◽  
Jin-Baek Kim ◽  
Jin-Ho Kang

Compared to the studies on acute irradiation of seeds, fewer studies have reported on the chronic irradiation of seedlings, especially in fruit-bearing vegetables. We examined the effects of chronic gamma irradiation on tomato (Solanum lycopersicum ‘Micro-Tom’) seedlings exposed to gamma rays (50, 100, 150, and 200 Gy) for 4 weeks. As the total dose of gamma rays increased, leaf length, trichome density, and seed number were reduced in the irradiated seedlings (M1). Additionally, a change in fruit shape was observed. Chronic gamma irradiation reduced the expression of two trichome-related genes and affected the expression levels of 11 reactive oxygen species (ROS)-related genes. We examined the transmittance of these effects using M2 plants. The trichome density and fruit shape were similar between M2 and control plants; however, a reduction in leaf length and seed number was detected in M2 plants. Interestingly, changes in the expression of four ROS-related genes (ZAT10, Mn-SOD, POD3, and RBOH1) found in M1 were detected in M2 plants. Thus, the changes in phenotype and gene expression induced by chronic gamma irradiation were transmitted to the next generation. Additionally, we found novel mutants from M2 plants, suggesting that chronic gamma irradiation may be considered in tomato mutation breeding.


2015 ◽  
Vol 35 ◽  
pp. 1-5 ◽  
Author(s):  
S. Umavathi ◽  
L. Mullainathan

The present study was conducted in order to determine the effect of gamma rays and EMS on seed germination, Seedling height and root length in chick pea to identify the lethal dose (LD50). In this regard, the healthy seeds of chick pea was subjected to different doses/concentrations of gamma rays (20, 30, 40, 50 and 60kR) and EMS (10, 20, 30, 40 and 50mM) for inducing mutation. The effect of gamma rays and EMS was determined by measuring the seed germination, seedling height and root length under the conditions of the M1 generation. The results shows that, the seed germination, seedling height and root length were significantly decreased with increasing doses/concentrations. The LD50 values were observed based on the growth reduction of seedlings after treatments with mutagen. The effective doses/concentrations which caused 50% growth reduction were observed in 40kR in gamma rays and 30mM in EMS.


2015 ◽  
Vol 5 (4) ◽  
pp. 9-15
Author(s):  
Thanh Long Nguyen ◽  
Quang Luan Le

The mixtures β-glucan extracted from the yeast cell wall were irradiated under gamma rays from a Co-60 source at doses of 100, 200 and 300 kGy in order to prepare water-soluble β-glucan. Yields of the water soluble β-glucan produced are 25.9, 49.1, 66.71%, and their molecular weights (Mw) are 30.5, 24.9 and 10.8 kDa, respectively. There are no any new peak in the IR spectra of the irradiated β-glucan samples, but the intensity ratio between the peaks at wavenumber of 1156 cm-1 (assigned to C-O-C bond) and of 1040 cm-1 (assigned to C-C bond) in glycosidic linkages was reduced with irradiation dose. These results revealed that gamma irradiation did not cause any change in the β-glucan structure except the scissions of glycosidic linkages. In this study, immuno stimulation of the irradiated b-glucan was also investigated for the Swiss mice. After 28 days supplying with the irradiated b-glucan, not only cellular indexes (white blood cell, neutrophils and lymphocytes counts), but also humoral  immunity indexes (IgA and IgM) of the mice significantly increased and the highest effects was obtained for the mice supplied with the oligoβ-glucan prepared by gamma irradiation at 200 kGy. Thus, the water soluble oligoβ-glucan with Mw ~ 24.9 kDa prepared by gamma radiation much stimulated the natural immune system (non-specific immunity) in mice including both the cellular and humoral immunities. Particularly, the irradiated b-glucan is a very promising product for preparation of functional foods aiming at cancer prevention.


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