Effect of Two Nitrogen Forms on the Growth and Iron Nutrition of Pea Cultivated in Presence of Bicarbonate

ABSTRACT

Two cultivars of pea: ‘PS210713’ (‘PS’), sensitive to iron deficiency, and ‘Marveille de Kelvedon’ (‘MK’), tolerant, were cultivated in controlled climatic conditions during one month, on a nutrient solution containing either nitrate (NO₃ ^?, 4 mM) or ammonium (NH₄ ⁺, 4 mM) and in the presence of bicarbonate (10 mM). The effects of these nitrogen forms on the growth and the mineral nutrition, and especially iron nutrition are analyzed.

The reduction of growth by bicarbonate was approximately 30% in case of NO₃ ^? nutrition in the two cultivars, whereas in ammoniacal treatment the reduction is only 6% and 18% respectively in ‘PS’ and ‘MK’ cultivars.

In presence of bicarbonate, the plant growth is not stimulated by NO₃ ^?relatively to its growth on ammoniacal medium, as often noticed when plants are cultivated on medium without bicarbonate: In presence of this compound, the biomass production of plant pea, was not influenced by the nitrogen forms. The nitric source led to a ferric chlorosis in the sensitive cultivar plants whereas any chlorosis was noted when ammoniacal source was applied. On the other hand, nitric nitrogen form decreased the nitrogen feeding of plants and increased the potassium one, while the effect of the ammoniacal nitrogen form on these nutrients was quite the inverse. In addition, the later increased the allocation of iron towards shoots. Besides, with this nitrogen source there was not accumulation of nitrate in the plant tissues. In nitric feeding case, the nitrate is mainly accumulated in the roots of the two cultivars. It is noticeable that the sensitive cultivar (‘PS’) accumulates three times more nitrate than the tolerant one (‘MK’).

On the level of the whole plant, the iron and phosphorus nutrition seems unaltered by the nitrogen form.     

Retention of xenon in quartz and Earth's missing xenon

The reactivity of xenon with terrestrial oxides was investigated by in situ synchrotron x-ray diffraction. At high temperature (T > 500 kelvin), some silicon was reduced, and the pressure stability of quartz was expanded, attesting to the substitution of some xenon for silicon. When the quartz was quenched, xenon diffused out and only a few weight percent remained trapped in samples. These results show that xenon can be covalently bonded to oxygen in quartz in the lower continental crust, providing an answer to the missing xenon problem; synthesis paths of rare gas compounds are also opened.     

Photosynthetic responses to phosphorus nutrition in two-year-old maritime pine seedlings

We analyzed processes limiting photosynthesis in two-year-old, container-grown Pinus pinaster Ait. seedlings subjected to phosphorus (P) deficiency. After withholding P for 3 months, seedlings were supplied P at four relative addition rates (0, 0.005, 0.01 and 0.02 day(-1)) in a nutrient recycling system. At Weeks 12 and 22, responses of photosynthesis to CO(2) and irradiance were measured and the following parameters derived: maximal velocity of carboxylation by Rubisco, V(m); apparent quantum efficiency of electron transport, alpha maximal electron transport rate, J(m); stomatal conductance and relative stomatal limitation of photosynthesis. At Week 22, these measurements were combined with concurrent measurements of chlorophyll fluorescence to determine the quantum yield of PSII, and a theoretical partitioning of total light-driven linear electron flow between fractions used to regenerate carboxylated and oxygenated RuBP. After 12 weeks of treatment, needle P concentrations ranged from 0.04 to 0.15 x 10(-2) g g(DW) (-1), and then remained constant until Week 22. Values of J(m), alpha and V(m) increased with increasing needle P concentration (from 30 to 133 &mgr;mol m(-2) s(-1), 0.02 to 0.25 mol mol(-1) and 13 to 78 &mgr;mol CO(2) m(-2) s(-1) at the lowest and highest needle P concentrations, respectively). Under ambient conditions, net assimilation rates in P-deficient seedlings were limited by V(m) under saturating irradiance, and by J(m) under limiting irradiance, but not by triose-P regeneration. There was no detectable change in the partitioning of total light-driven linear electron flow between the fractions used for carboxylation and oxygenation. Predawn photochemical efficiency of PSII was significantly reduced in seedlings with low P concentrations. Although stomatal conductance tended to decrease with decreasing needle P concentration, relative stomatal limitation was not significantly affected. At Week 22, there was an attenuation of the effects of P nutrition on V(m) and an increase in alpha and J(m) that was probably related to cessation of growth and the seasonal decline in natural irradiance.     

Early heat acclimation during incubation improves Japanese quail performance under summer conditions

Effects of exposing quail eggs to high temperature on the heat tolerance ability and productivity of birds were investigated. Four groups of 600 fertile eggs were randomly selected; the first group was incubated under 37.5 °C and the hatched chicks were reared under a gradual decrease in temperature from 35 to 24 °C (Control). The second group was exposed to 39.1 °C for 2 h/day during 4–14 days of embryogenesis and the hatched chicks were reared under a gradual decrease in temperature from 35 to 24 °C. The third group was incubated under 37.5 °C and the hatched chicks were exposed to 39?±?1 °C for 2 h/day during 4–14 days of age. The fourth group was exposed to 39?±?1 °C for 2 h during 4–14 days of embryogenesis and the hatched chicks were exposed to 39?±?1 °C for 2 h/day during 4–14 days of age. The temperature applied changed (P?<?0.01) embryo weight and incubation period. Birds exposed to high temperature during brooding had superior growth performance, dressed carcass, body temperature and health traits. Birds subjected to 39?±?1 °C during brooding exhibited decreased feed consumption and body weight gain. Finally, this work suggests that thermal acclimation during embryogenesis might offer a practical method for easing heat stress.

     

Preparation of Polyurethane Silicon Oxide Nanomaterials as a Binder in Leather Finishing

Leather finishing processes using toxic organic solvent based produce volatile organic compounds (VOC), chronic exposure to this chemicals effect on workers' health causing many diseases especially lung cancer. So, polyurethane waterbased was synthesized for application in leather finishing instead of organic solvent based because it’s economic and safety for industry and workers. Preparation of water-based polyurethane (PU) depends on the reaction of polyethylene glycol (PEG, 300) with isophorone diisocyanate (IPDI) and the reaction of IPDI-1,4-butanediol (BDO) together with dimethylolpropionic acid (DMPA), was synthesized by poly-addition polymerization reaction. PU was then modified with different amounts of silicon dioxide nanoparticles (1-5 % SiO₂), used as a binder in leather finishing. Leather coated was characterized physically, chemically and thermally by FTIR, GPC, DLS, TEM, SEM and TGA. The results revel that, water vapor permeability (WVP) of leather coated with PU modified with SiO₂ showed improvement due to the existence of SiO₂ particles which increases the interspaces of the polyurethane coating. SEM showed that when the amount of SiO₂ nanoparticles increases, there is uniform nanoparticles accumulated can be observed. EDX prove the presence of Si and O₂ elements and the formation of SiO₂ nanoparticles. Mechanical properties discussed that tensile strength; tear strength and elongation at break % increase with increase SiO₂ concentration until 3 % SiO₂ nanoparticles. TGA showed an improvement of thermal stability of coated leather modified with SiO₂. Therefore, this study succeeded in preparation of safe, ecofriendly of water-based polyurethane binders which modified with SiO₂ for using in leather finishing.     

Biochemical and histological effects of gibberellic acid on Locusta migratoria migratoria fifth instar larvae

Experiments were conducted to assess the effect of gibberellic acid (GA₃), a plant growth regulator, on Locusta migratoria migratoria fifth instar larvae. Newly emerged larvae were exposed to various concentrations of GA₃ administered by topical application or by forced ingestion. Results showed that treated insects exhibited toxic symptoms with a dose-dependent mortality. GA₃ toxicity was also demonstrated by perturbation of the moult processes. In fact, we noted that treated insects present exuviations difficulties due to the impossibility to reject the old integuments causing mortality in the 5th instar larvae. Histological study of proventriculus revealed alterations in the epithelial cells and absence of apolysis phenomenon. Data also showed that GA₃ induced significant quantitative variation of haemolymph metabolites. These changes result in a significant decrease in the total concentration of proteins and carbohydrates and an increase in the total concentration of haemolymph lipids.     

Adaption of a formula for simulating bedload transport in the Nile River,Egypt

Journal of Soils and Sediments - Bedload transport discharge is important in river engineering and morphodynamics. The Meyer-Peter and Müller (MPM) equation for determining bedload transport...     

Chemical composition, iron bioavailability, and antioxidant activity of Kappaphycus alvarezzi (Doty)

Kappaphycus alvarezzi, an edible seaweed from the west coast of India, was analyzed for its chemical composition. It was found that K. alvarezzi is rich in protein (16.24% w/w) and contains a high amount of fiber (29.40% w/w) and carbohydrates (27.4% w/w). K. alvarezzi showed vitamin A activity of 865 mug retinal equivalents/100 g of sample. It contained a higher quantity of unsaturated fatty acids (44.50% of the total), in which relative percentage of oleic acid was 11%, cis-heptadecanoic acid 13.50%, and linoleic acid 2.3% and 37.0% of saturated fatty acids (mainly heptadecanoic acid). K. alvarezziwas also found to be good source of minerals, viz 0.16% of calcium, 0.033% of iron, and 0.016% of zinc, which are essential for various vital biological activities. Bioavailability of iron by in vitro methods showed a higher efficiency in intestinal conditions than in stomach conditions. Ascorbic acid influenced higher bioavailability of iron. Successive extracts of n-hexane, acetone, ethyl acetate, ethanol, and direct extractables of chloroform/methanol (1:1 and 2:1) were screened for antioxidant activity using a beta-carotene linoleic acid model system (B-CLAMS), DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) model system and hydroxyl radical scavenging activity. The chloroform/methanol (2:1) extract has shown 82.5% scavenging activity at 1000 ppm. Acetone fraction extracts at the 1000 ppm level showed 63.31% antioxidant activity in beta-carotene linoleic acid system. The acetone extract showed 46.04% scavenging activity at 1000 ppm concentration. In the case of hydroxyl radical scavenging activity, all the extracts showed better activity at the concentrations of 25 and 50 ppm, where at the 50 ppm level ethyl acetate extract showed 76.0%, acetone 75.12%, and hexane 71.15% activity, respectively. Results of this study suggest the utility of K. alvarezzi (Eucheuma) for various nutritional products, including antioxidant for use as health food or nutraceutical supplement.