scholarly journals The ameliorative effect of selenium on Azolla caroliniana grown under UV-B stress

2015 ◽  
Vol 95 (1) ◽  
pp. 20-26 ◽  
Author(s):  
E.M. Mostafa ◽  
A.M.A. Hassan

Exposure ofAzollaplants to UV-B radiation for 6 h resulted in a decrease in biomass and relative growth rate (RGR), which coincided with an increase in doubling time (DT) as compared with the control. Also, the protein content decreased. On the other hand, hydrogen peroxyde (H2O2) and malondialdehyde (MDA) accumulated significantly in UV-treatedAzollaplants. Conversely, the addition of selenium (Se) at 1 ppm resulted in a significant increase in biomass and protein content of untreated and UV-treatedAzollaplants, and a significant reduction in both H2O2and MDA. Moreover, the addition of Se to UV-treated and untreatedAzollaplants resulted in a significant increase in total ascorbate and total glutathione (GSH) contents compared with the control and UV-stressedAzollaplants. Also, glutathione redox potential (GSH/TG) increased significantly in UV-treatedAzollaplants in the presence of Se. There also was a significant increase (38%) in ascorbate peroxidase (APX) activity in UV-treated plants compared with the control. APX activity in the presence of Se did not change significantly compared with the control. Glutathione reductase (GR) activity increased significantly in UV-treatedAzolla, while glutathione peroxidase (GSH-PX) activity did not. On the other hand, both GSH-PX and GR activity in untreated and UV-treatedAzollaplants were significantly enhanced by the application of Se to the nutrient media at a concentration of 1 ppm. Therefore, we can conclude that Se protectsAzollaplants from UV-B stress.

2007 ◽  
Vol 62 (3-4) ◽  
pp. 246-252 ◽  
Author(s):  
Mohamed M. Ibrahim ◽  
Eazaz M. Mostafa

Abstract Changes in growth and ultrastructure of Azolla caroliniana in response to elevated UV-B radiation were investigated. Exposure of plants to UV-B radiation for 1, 8, 16, 24 and 48 h exhibited a significant decrease in biomass and relative growth rate. This decrease resulted in an increase in doubling time over the control. Also, Chl a and b contents were significantly decreased especially after 16 h. The reduction was accompanied by a decrease in 5-aminolaevulinic acid content (precursor of chlorophyll). On the other hand, contents of carotenoid and UV-absorbing phenolic compounds (flavonoids and anthocyanins) were increased.


2021 ◽  
Vol 22 (1) ◽  
pp. 131-142
Author(s):  
Mohammad Ebrahim Ahmed ◽  
Hussain Yawr Hussain

Thirty-six local dose have been used and were divided in to three groups sacording to weight, in each group twelve dose. In the first group the weights of the dose were higher than ( 2.5 kgs) and less than (3 kgs). The second groups was higher than 3 kgs) and less than (3.5 kgs). The third group was higher than (3.5 kgs) and less than (4 kgs). The aim of this study was to obtain the effect of doe weight on her reproductive efficiency (gestation period, litter size, litter weight at birth and weaning, growth rate of offspring preweaning, conception rate and preweaning mortility).  The weight of the doe had no significant effect upon the gestation period and this period was 30.9, 31.2, 31.3 days for the three groups respectively, on the other hand the litter size was affected significantly by doe weight and litter size was at birth and preaweaning (5.1 , 5.8 and 6.2), (4.5, 5.3 and 5.7) for the three groups respectively. The offspring weight at birth and weaning was affected significantly by doe weight and this weight was (40.1 , 48.2 and 53.3 gms), (203.6, 227.5 and 233.8 gms) for the three groups respectively while the conception rate was not affected by doe weight. The mortility percentage in the prewaning period was not significantly by doe weight


2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Oladosu O. Oladimeji ◽  
Olayanju O. Oladimeji

This research paper's main objective is to quantify and analyze the research output of data mining in West Africa, including (1) growth in publications as measured by the Relative Growth Rate (RGR) and Doubling Time (Dt), (2) productivity and quantification of research output for different institutions of the region (West Africa).


2019 ◽  
Vol 9 (1) ◽  
pp. 85-89
Author(s):  
Nutan Gaud ◽  
M. P. Singh ◽  
Bhoopendra Singh

The present study aims to analysis authorship pattern and collaboration coefficient of library professional’s competency publications research from 1999-2018. The data has been downloaded by Scopus database. A total number of published articles during the period of study was 433 in the particular database on the topic of ‘professional’s competency’. The study examine various scientometric parameter such as authorship pattern, year wise distribution of publication, determine the annual growth rate and compound annual growth rate of publication, relative growth rate and doubling time of publication and so many. After the analysis, it is found that the highest 11.78% of an article published in the year 2015. The highest growth rate in 2000 and the lowest in 1999. The United States published highest 174 article and secured first place in top five countries wish distribution of the publication. Majority of the article is published by single authors is 171 articles during the period of study.


2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Moussa Side ◽  
Eby Yoboué Gnamma Honorine Alla ◽  
Behiri Innocent Kakou ◽  
Béatrice Abouo Adepo-Gourene

The growth and size at first sexual maturity of the species Ethmalosa fimbriata were studied in two sites in the Ebrié lagoon: Bietri, a highly anthropized environment and Vitré 2, a reference site. Growth parameters estimated from size frequencies showed that growth in both size and weight was faster in females than in males regardless of habitat. On the other hand, specimens from Biétri bay have a slower growth rate than those from Vitré 2. In Bietri bay, individuals are characterized by early sexual maturity. They reach sexual maturity at the age of 0.55 years (about 7 months), corresponding to a size of 6.13 cm for males and 8.42 cm for females; whereas in Vitré 2, they reach sexual maturity at the age of 0.82 years (about 10 months) corresponding to a size of 10.22 cm and 12.94 cm for males and females respectively. These results show that in a highly antropic environment, the growth of Ethmalosa fimbriata is affected and individuals reproduce earlier.


1987 ◽  
Vol 65 (8) ◽  
pp. 1638-1642 ◽  
Author(s):  
L. A. C. J. Voesenek ◽  
C. W. P. M. Blom

Root development and architecture were studied in three Rumex species growing in a perforated soil system in the greenhouse. Distinct differences in vertical root distribution under drained conditions were found among the three species. Rumex acetosa and R. palustris had a relatively superficial root pattern, whereas in R. crispus much of the root growth was concentrated in lower soil layers. In the upper soil layer the relative growth rate of the roots of R. palustris was significantly larger than that of the other species. A relation between the characteristic rooting patterns under drained conditions and the Rumex zonation in the field is discussed.


2008 ◽  
Vol 600-603 ◽  
pp. 227-230 ◽  
Author(s):  
Yoshimine Kato ◽  
Kazuo Sakumoto

SiC growth on as-received and striated Si(001) substrates was studied. SiC films were grown by pulsed-jet chemical vapor deposition using monomethylsilane as a gas source at 780°C. Two kinds of Si surfaces were prepared. One was an as-received Si(001) surface and the other was an striated (scratched) Si(001) surface. It was found that nucleation rate of SiC is quite different between these two kinds of surfaces. The film growth rate was very low for the as-received Si(001) surface compared with the striated surface, and after 8 hours of growth hardly any film was grown and only square-shaped islands were observed. On the other hand, for the undulant substrate about 100nm thick 3C-SiC film was grown after 8 hours of deposition. This film growth rate difference appears to be due to the difference in density of nucleation sites. For the as-received Si(001) surface, nucleation site density appears to be quite small due to the atomically flat surface. On the other hand, for the undulant surface, nucleation site density was large enough for the film to grow faster.


2013 ◽  
Vol 740-742 ◽  
pp. 205-208
Author(s):  
Galyna Melnychuk ◽  
Siva Prasad Kotamraju ◽  
Yaroslav Koshka

In order to understand the influence of the Cl/Si ratio on the morphology of the low-temperature chloro-carbon epitaxial growth, HCl was added during the SiCl4/CH3Cl growth at 1300°C. Use of higher Cl/Si ratio allowed only modest improvements of the growth rate without morphology degradation, which did not go far beyond what has been achieved previously by optimizing the value of the input C/Si ratio. On the other hand, when the epitaxial growth process operated at too low or too high values of the input C/Si ratio, i.e., outside of the window of good epilayer morphology, any additional increase of the Cl/Si ratio caused improvement of the epilayer morphology. It was established that this improvement was due to a change of the effective C/Si ratio towards its intermediate values, which corresponded to more favorable growth conditions.


2019 ◽  
Vol 4 (1) ◽  
pp. 1-4
Author(s):  
MA Ebrahiem

The study aimed to investigate the impact of supplementary feeding on the young camels calve growth rate and daily gain. A total of 16 heads of young male camel calves from the Arabic camel breeds were selected and div ided into four equal groups (1, 2,3,4). Four heads of camel calves in each group, their body weight ranged from 176 - 220 kg. Experimental animal in group one was control supplemented nothings jus t depend on the natural range land, group two was feed on watermelon seeds, group three was allowanced concentrated diet composed of ground nut cake and the animals in group four intake mixture diet consist of watermelon seeds and ground nut cake 50% for e ach. The body weight of the experimental animal was determined biweekly using table balance. The random complete experimental design was used and the Analysis of variance and Tukey test were applied for data analysis and means separation. The results indic ated that the average Body weights of the camel calves were 174.75±3.3, 275.93± 9.0, 241.50± 8.5 and 236.50±8.2 Kg, in group one, two, three and four respectively. The higher body weight was recorded in group two (275.93±9 Kg) in which the animals feed on watermelon seeds and followed by group three and four (241.50± 8.5 and 236.50±8.2) respectively. On the other hand the less camel calves body weight was obtained in group one (control) that experimental animals not intake supplementary feeding. Highly diff erences (P ≤ 0.01) were obtained in the body weight between the groups. The daily gain of the first group, second, third and fourth were 214±12g, 624±28g, 542±19g and 528±12g, respectively, while no significant differences (P ≥ 0.01) between diets groundnut cake 242 kg and mixture diet 237 kg. The protein content was higher in ground nut cake 41% when compared to the protein content in watermelon seeds 36%, on the other hand the percentage of fat was highest in watermelon seeds 27.8% compared to ground nut ca ke 13.4%.


Sign in / Sign up

Export Citation Format

Share Document