modern research physics

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This experiment was performed to determine the suitable quantity of highly unsaturated fatty acids (HUFA) for survival and growth of female broodstock of White leg shrimp (Litopenaeus vannamei) during a 2- months culture period (from Apr 3 to Jun 4, 2008). Brood feed was similar in all treatmints containing and Isonitrogeneous (31.5 % protein): but the only difference between dry diets of the test was varying levels of HUFA (1, 2 and 3%). This research tested the effect of dietary HUFA on the survival ratio (SVR) and the body weight (%WG) and body length (% L), compared to those fed on fresh meals (Prenereis worm, melalis and cuttlefish). The survival ratio didn’t differ significantly between all diets (P>0.05). The (% L) in control diet was significantly higher than other treatments (P<0.05) and then1% HUFA diet was significantly higher. The (%WG) in 1% HUFA diet was significantly higher comared to other treatments (P<0.05).

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The effects of cadmium and iron interaction on some physiological parameters in rice (Oryza sativa L.cv.fajr) plant were studied. The four days old seedlings were transferred to pots containing sand, irrigated with Hoagland solution in growth chamber. The 15 days old plants were treated with 0, 50 and 100 &muM  CdCl2 supplemented with 5, 10 and 20 ppm Fe as Fe-EDTA. Plants were grown under controlled condition and harvested after 30 days for measurements of some biochemical and physiological parameters. Treatments were conducted with four replications. Under Cd stress, growth of plant decreased. In plants treated with CdCl2, relative growth rate, net assimilation rate and photosynthetic rate were decreased. Addition of Fe-EDTA (10 and 20 ppm) moderated cadmium effects. Under Cd stress without Fe, respiration rate and CO2  compenstation point increased, however, in solutions containing both CdCl2 and Fe-EDTA, respirations rate and CO2  compenstation point decreased. In plants treated with CdCl2, catalase activity increased. However, after increasing Fe in solution containing CdCl2, catalase activity decreased. Therefor, the results indicated that in CdCl2 treated plants with increasing Fe-EDTA, the toxic effects of Cd decreased.

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Oil pollutions as a consequence of increasing consumption of petroleum, have a tremendous effect on water and soil ecosystems and their microflora. In this study the diversity in physiological parameters, including growth rate, photosynthesis, chlorophyll-a and phycobiliproteins content, between cyanobacterial strains flora isolated from oil-polluted and non-polluted areas, were assessed. To this end, strains were isolated and purified. The experiments were carried out on logarithmic phase cultures of the isolates in suitable liquid media. The chlorophyll and phycobiliproteins contents were determined using a colorimetric method. Photosynthesis was measured by Oxyview apparatus. Growth rates were calculated based on dry weights. Under laboratory conditions, the photosynthesis activity and the chlorophyll content of isolates from oil-polluted sites were significantly lower than non-polluted isolates. On the other hand, the growth rate average of strains from oil-polluted sites was significantly higher than non-polluted strains. Also despite the higher phycobiliproteins content in non-polluted isolates, there was no significant difference in any of these pigments between the two groups. Altogether the results showed that in response to petroleum stress, the cyanobacteria restore the decrease in their chlorophyll content and photosynthesis activity by increasing their biomass. In fact the response is the reflects of restructuring cyanobacterial flora from sensitive autotrophic species to oil-pollution resistant mixotrophic species in the polluted ecosystems that in addition to photosynthesis are able to use crude oil as an energy source for their growth requirements, hence overcome the energy loss due to reduction of photosynthesis and even increase growth rate than non-oil-pollution isolates.

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Acid rain, which is a wet form of gaseous air pollutants, is formed when air pollutants such as SO₂, NO₂, CO₂ in atmosphere combine with water vapor of clouds. With the addition of concentration of these pollutants the amount of acid rain is increases. Acid rain that is the mixture of sulphuric acid, nitric acid and carbonic acid lead to change in the soil like the decrease in pH, nutrient liberation, the increase of releasing in toxic metals and the decline in fertility of soil that these cases results negative effects on plants. In present work wheat plants irrigated  and leaf spraied with  four treatments of acid rain which contain sulphuric acid and nitric acid with  pH= 2.5, 3.5, 4.5, 5.6 for a period of 32 days, whereas, control plants irrigated and leaf spraied by normal water at  pH= 7.4 . According to the results control plants in whole of growth and physiological indexes were better than treatments of  acid rain at pH= 2.5 and 3.5, also plants of acid rain treatment at pH= 4.5 and 5.6, were lower in other factors except photosynthetic rate, pigment content and carbohydrate content than control plants. Also acid rain at pH= 2.5 and 3.5 causes white spot in both surface of  leaf and tip and border atrophy.

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In the larviculture the use of high quality dietary components is critical for rearing fish. Artemia nauplii and decapsulated cyst have very wide usage on aquaculture industry. In most of fish species, especially in fresh water fish’s larvae stage, Artemia nauplii and decapsulated cyst have very important effects on growth rate and survival. In this study, effect or different initial feeding upon the second growth rate of trout larvae stage was studied. To this end, the new absorbed yolk sack trout larvae were used. All larvae in five feeding treatments(artemia nauplii, decapsulated cyst, commer-cial diet mixed with decapsulated cyst, commercial diet mixed with nauplii, commercial diet) for 20 day with intensity 6 larvae per litter at tanks 35-liter were reared. Then experiment extended in these treatments with the commercial diet (only) for 20 days more. Larvae fed with the artemia nauplii in the first experiment had the highest growth and the difference was significant compared with the other treatments (p<0.05). In the second experiment, after 20 day in the all treatments, the growth rate, survival, SGR, FCR, condition factor, feed intake rate, Gross efficiency were measured. Results showed that in the second 20-day period, the larvae fed with commercial diet mixed with decapsulated cyst treatment in first experiment, had a significant difference with the other treatments (p<0.05).The fish that were fed with decapsulated cyst mixed with commercial diet had the highest growth rate rather than the other treatments.

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In a green house pot experiment, the effects of salinity and increasing levels of potassium supply on factors determining dry matter production of two barley cultivars(Reyhan and Afzal) were investigated, with regard to yield (Number of tillers and ears, dry weight of ears, straw, roots, thousand grain weight and leaf area). The plants were grown under four levels of potassium (K1= 0,K2=./25, K3 =./5 and K4=1 gr. K/Kg. soil) and 40mM NaCl in a randomized complete blocks design with four replication. The results indicated that by using of NaCl, the number of ears, dry weight of ears, thousand grain weight, biomass and leaf area increased, whereas dry weight of roots ,the number of tillers per plant ,duration of grain filling and maturity period in both cultivars decreased. Increasing of potassium supply significantly increased dry weight of shoots during vegetative growth, but during reproductive- and maturity growth had no marked influence on dry weight production. By increasing the levels of potassium accompanied with salinity no effects on above mentioned parameters were observed. This may be due to a high availability of potassium in the soil , which led to an increase in dry weight of the plant shoots.