Efficiency of screening criteria for drought tolerance in chickpea

Crop drought tolerance improvement is one of the most challenging objectives of plant breeding programs. Developing an efficient screening technology and access to genetic variation for the traits contributing toward drought tolerance are major steps in this direction. To go in this quest, an experiment was conducted under controlled condition in a greenhouse. Nine Kabuli chickpea genotypes were grown under well-watered condition (85–90% field capacity (FC)) until start of flowering. Then, the following water treatments were imposed: well-watered, intermediate (55–60% FC), and severe (25–30% FC) drought stress. Physiological and agronomical traits were compared under different water treatments. Drought stress and genotypes interaction was significant in all measured traits, indicating that various genotypes responded differently to drought stress. Among measured traits, electrolyte leakage, stomatal conductance, yield components, and harvest index exhibited the highest variations. Yield components and stomatal conductance showed maximum reduction under drought stress and in susceptible known genotype, ILC3279, reduction reached up to 95%. Principal component analysis indicated that relative water content, photochemical efficiency of photosystem II, and stomatal conductance are the physiological traits with greater contribution toward drought tolerance. Therefore, these traits should be evaluated ahead of many other traits in making selections for drought-tolerant chickpea genotypes.     

Effect of photoperiod and feeding frequency on growth and feed utilization of fingerlings Persian sturgeon (Acipenser persicus)

The effects of photoperiod (12L:12D and 18L:6D) and feeding frequency (three, four and five evenly spaced daily feedings) of 10% biomass per day during light hours on growth and stress response of Persian sturgeon (Acipenser persicus) fingerlings were evaluated. The interaction between photoperiod and feeding frequency was not significant (P>0.05). Faster growth was observed in fish exposed to an 18L:6D photoperiod (P<0.01). The feed conversion efficiency (FCE) was also better with an 18L:6D photoperiod (P<0.05). Fish fed four and five meals per day grew similarly (P>0.05) and faster than when fed only three meals (P<0.01). The FCE with four or five meals per day was better than with three meals (P<0.05). At harvest, the proximate composition was similar in all treatments (P>0.05). Stress indicators (cortisol, glucose and haematocrit) did not differ between photoperiods (P<0.05). The results showed that 0.9–8.0 g Persian sturgeon fingerlings should be reared with an 18L:6D photoperiod and fed four times per day to obtain good growth and FCE.     

Effects of Mg-Al Layered Double Hydroxide on Nitrate Leaching and Nitrogen Uptake by Maize in a Calcareous Soil

The potential use of a layered double hydroxide (magnesium aluminum nitrate (Mg-Al)-LDH) to suppress the leaching of nitrate from a calcareous sandy loam soil and to enhance the nitrogen utilization efficiency of maize was assessed. The results of column studies showed that nitrate leaching efficiently decreased by 24, 46, and 76% compared to control when 2.5, 5, and 10 g LDH kg^–1 soil were applied, respectively. Nitrate leaching was also reduced by use of LDH in pot experiments. The hindrance effect of LDH in using ammonium nitrate was higher than urea. Application of 2.5, 5, and 10 g LDH kg^–1 soil increased mean nitrogen uptake of maize by 14, 20, and 44% over the control. The studied LDH has a potential to be used as a nitrate-selective exchanger to reduce risks of nitrate leaching. However, the use of Mg-Al-LDH (4:1) can be limited because of its relatively high solubility in soil.     

Hygroscopic thickness swelling rate of composites from sawdust and recycled plastics

The thickness swelling rates of compression molded wood plastic composites (WPCs) prepared from 50% by weight sawdust and 50% by weight virgin and/or recycled plastics (HDPE and PP) were studied. Thickness swelling rates of the manufactured WPCs were evaluated by immersing them in water at room temperature and monitoring thickness changes for several weeks. A swelling model developed by Shi and Gardner (Composites Part A, 37:1276–1285, 2006) was used to study the thickness swelling process of WPCs. The parameter K _SR of the model can be used to quantify the swelling rate. The results indicated that composites containing PP had lower equilibrium thickness swelling and also shorter equilibrium time (time to reach equilibrium thickness swelling). The swelling model developed was a good predictor of the hygroscopic swelling process of wood plastic composites. Composites containing PP (virgin and recycled) had higher K _SR than those containing HDPE. The minimum and maximum K _SR values were observed in composites made of virgin HDPE and a mixture of recycled plastics, respectively. With increasing recycled plastic content K _SR linearly decreased.     

Pedological Investigation of a Litho-Toposequence in a Semi-Arid Region of Southwestern Iran

Eurasian Soil Science - A litho-toposequence of soils in a semi-arid region in southwestern Iran was investigated for their pedological properties. Nine representative pedons on different...     

Effects of different salinity and temperatures on the growth,survival, haematocrit and blood biochemistry of Goldfish (Carassius auratus)

The aim of the present study was to investigate the effects of different salinities (0‰, 6‰ and 12‰) and temperatures (23, 27 and 31 °C) on the food consumption, growth, blood biochemistry and haematocrit of Goldfish. After 45 days of exposure to different salinities and temperatures, Goldfish showed a good adaptation to these salinities and temperatures in terms of blood biochemistry (glucose and triglyceride) and haematocrit. Salinities (0‰ and 6‰) and temperatures (23 and 27 °C) did not affect the weight gain, specific growth rate, final biomass and feed conversion rates, but these parameters were significant (P<0.05) at 12‰ salinity and 31 °C temperature. Plasma total protein levels decreased with the increase in salinity (P<0.05), while they were independent of temperature. In conclusion, Carassius auratus, a freshwater stenohaline fish, showed good growth in saline waters with maximum 12‰ salinity and 31 °C temperature.     

The Influence of Cadmium Toxicity on Some Physiological Parameters as Affected by Iron in Rice (Oryza Sativa L.) Plant

The effects of interaction between cadmium chloride (CdCl₂) and iron (Fe)- ethylenediaminetetraacetic acid (EDTA) were studied in rice plant. The seedlings of rice were treated with 0, 50, and 100 μM CdCl₂ supplemented with 5, 10 and 20 ppm Fe as Fe-EDTA for 30 days. Plants were grown under controlled condition. In all the plants treated with CdCl_2, growth parameters [relative leaf growth rate (RLGR), specific leaf area (SLA), and leaf water content area (LWCA)], soluble, and unsoluble sugars contents decreased. Addition of Fe-EDTA moderated cadmium effects. Under CdCl₂ stress without Fe, malondialdehyde (MDA) content, proline content, catalase (CAT) and peroxidase (POD) activity increased, however, in solutions containing both CdCl₂ and Fe-EDTA, MDA content, proline content and activities of antioxidant enzymes decreased. In 50 μM CdCl₂, total protein content increased but in 100 μM decreased. With increasing Fe in solutions containing CdCl₂, protein content decreased. The results indicated that with increasing Fe-EDTA in CdCl₂ treated plants, the effects of toxicity of Cd decreased.