Growth and nutrient and nitrate accumulation of lettuce under different regimes of nitrogen fertilization

Abstract

For plant growth and composition, the effects of fertilizers including blood meal (BLO), cottonseed meal (CSM), dehydrated cow manure (COW), and urea (UREA) factored with lettuce (Lactuca sativa L.) of different morphological phenotypes including iceberg, romaine, loose head, and loose leaf were studied in a greenhouse. Lettuce growth increased with increasing nitrogen (N) applications from 0 to 800?mg N/pot (kg), but the top application of BLO, CSM, or UREA suppressed yields. Lettuce grown with BLO, CSM, or UREA had higher concentrations of N than with COW. Nitrate-N concentration in leaves of all varieties exceeded some standards at high application of organic fertilizer or urea except for COW. In general, increasing N application resulted in higher concentration of NH₄-N in lettuce with increases in applications of fertilizers. Organic fertilizers and urea were equally effective in supporting growth and affecting nutrient accumulation in lettuce if sufficient N was supplied.     

Improving chilling tolerance of rice seedling by seed priming with salicylic acid

This study was carried out in the Seed Research Laboratory of the Department of Crop Science, Ferdowsi University of Mashhad, Iran, in summer 2011. Rice (cv. Khazar) seeds were soaked in 0, 20, 50, and 100 mg l^?1 salicylic acid (SA) aerated solutions for 24 h and then dried back to original moisture content and were sown in three temperatures (28°C as normal and 12°C and 8°C as chilling temperature conditions). In the first step, both treated and untreated seeds were sown at the optimum temperature (28°C). Then, to apply chilling temperature, 15 days after sowing, one set of the seeds was exposed to 12°C and 8°C under controlled conditions. Results showed that all seedlings raised from seeds primed with SA solutions produced a higher root and shoot length, final emergence percentage, and relative water content and also lower mean emergence time and time to 50% emergence (E50) in comparison with untreated seeds. Antioxidant enzyme system efficiently responded to the stress conditions and the priming treatment. Also seedling raised from primed seeds showed higher antioxidant activity at each temperature compared with control.     

Phenotypic and genetic parameter estimates for reproductive traits in Zandi sheep

This study reports on the phenotypic and genetic (co)variance components for reproductive traits in Zandi sheep, using between 1,859 and 2,588 records obtained from 577 ewes. The data were collected from the Khojir Breeding Station of Zandi sheep in Tehran, Iran from 1994 to 2008. The basic traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), and litter mean weight per lamb weaned (LMWLW), and the composite traits were total litter weight at birth (TLWB) and total litter weight at weaning (TLWW). Genetic analyses were carried out using the restricted maximum likelihood method that was explored by fitting the additive direct genetic effects and permanent environmental effects of the ewes as random effects and the ewe age at lambing and lambing year as fixed effects for all of the investigated traits. Akaike’s information criterion was used to choose the most appropriate model. LSB, LSW, LMWLB, LMWLW, TLWB, and TLWW direct heritability estimates were 0.07, 0.05, 0.12, 0.10, 0.08, and 0.14, respectively. The estimated fractions of variance due to the permanent environmental effects of the ewe ranged from 0.03 for LMWLB to 0.08 for LMWLW and TLWW. Corresponding repeatability estimates ranged from 0.10 for LSW to 0.22 for TLWW. Direct genetic correlations varied from ?0.61 for LSB–LMWLB to 0.88 for LSB–LSW and LSB–TLWB. Results indicate that genetic change depends not only on the heritability of traits, but also on the observed phenotypic variation; therefore, improvement of non-genetic factors should be included in the breeding programs.     

Pregnancy in the Caspian Miniature Horse Using Frozen Semen Cryopreserved with the EquiPRO CryoGuard Freeze Medium and Customized Freezing Protocols

The primary goal of this project was to establish a protocol to freeze the sperm of the Caspian miniature horse in an attempt to start an intensive artificial insemination program to effectively increase the population of this breed, which has been listed as “Critical Rare Breed” by the American Livestock Breed Conservancy and is in danger of extinction. Commercially available equine freezing medium (EquiPRO CyoGuard Complete egg-yolk extender) was used for the initial setup of two different freeze protocols: slow and fast. The fast-freeze protocol had slightly better postthaw results and was used for a fertility demonstration. Five mares of proven fertility, aged 3 to 12 years, were used in the fertility trials, two of which resulted in pregnancy. This is the first report of pregnancy in the Caspian miniature horse using frozen semen, and the results seem to be a promising start to an extensive program to help this endangered breed, although further research on freezing protocols and conditions for this process are necessary to further improve the survival of semen and pregnancy rate.     

Fate of Graywater Constituents After Long-Term Application for Landscape Irrigation

While interest in and adoption of graywater reuse for irrigation has rapidly grown in recent years, little is known about the long-term effects of graywater irrigation. Concerns exist in relation to the presence of pathogenic organisms, fate of personal care products, and accumulation of salts. The purpose of this research was to evaluate the long-term effects of graywater irrigation to soil quality under real conditions where homeowners may not always apply graywater in a highly controlled manner. Four households from different climatic and geological conditions were selected for sampling (AZ, CA, CO, and TX) where graywater was applied for irrigation for a minimum of 5?years. Soil samples were collected in areas irrigated with graywater and areas irrigated with freshwater within the same yard. Soil cores were taken at depths of 0?C15, 15?C30, and 30?C100?cm and analyzed separately for surfactants, antimicrobials, sodium adsorption ratio (SAR), electrical conductivity (EC), extractable boron, fecal indicator organisms (E. coli, enterococci, and Clostridium perfringens), and soil dehydrogenase activity. In surface soil samples (0?C15?cm), the average total surfactant concentration (over all sites) was higher in graywater-irrigated soil (0.078?±?0.033) compared to freshwater-irrigated soil (0.030?±?0.025?mg?kg^?1). This difference was not found to be significant (P?>?0.05). Triclosan and triclocarban were detected in surface soil samples at some locations (3.8?C6.3 and 3.5?C9.1???g?kg^?1, respectively), but not in samples deeper than 15?cm. Among the sampling locations, the TX household appeared to be most impacted by graywater, as evidenced by elevated SAR, potentially toxic levels of B, and relatively high numbers of E. coli and enterococci due to 30?years of graywater application for irrigation.     

Evaluation of the relationship between endometriosis and omega-3 and omega-6 polyunsaturated fatty acids

Background: Endometriosis is a common chronic inflammation causing major problems including infertility. The role of omega-3 and omega-6 fatty acids as their potential anti-inflammatory effects in endometriosis needs to be further explored. The objective of this study was to compare serum phospholipid fatty acid profile in endometriosis patients with controls, and to explore the correlation of this profile with the severity of the disease. Methods: Sixty-four endometriosis patients and 74 control women, in reproductive age, participated in this study. Among the endometriosis patients, 19 cases were in stage I, 27 cases in stage II, 8 cases in stage III, and 10 cases in stage IV. Each patient underwent laparoscopy. Before surgery, 5 ml of blood was obtained. After extraction of the total lipids, serum total phospholipid fraction was isolated by thin layer chromatography. Fatty acid composition of the phospholipid fraction was determined by gas chromatography and the resulted profile was compared in endometriosis patients and controls. The profile was also compared in the endometriosis group based on the severity of disease. Results: Stearic acid was significantly lower in the endometriosis group as compared to controls (P= 0.030). No other fatty acid compositions were significantly different between patients and controls. Serum ratio of eicosapentaenoic acid (EPA) to arachidonic acid (AA) was in reasonable correlation with the severity of endometriosis (r = 0.34, P = 0.006). Conclusion: According to these findings, levels of fatty acids in serum total phospholipids seem not to be a marker for endometriosis, but the EPA to AA ratio was a relevant factor indicating severity of illness.Key Words: Endometriosis, Phospholipids, Omega-3 fatty acids     

A portable scanning system for evaluation of spray deposit distribution

Preventing over- or under-spray applications on intended targets require a system to rapidly measure spray coverage and provide spray quality feedback information. A portable scanning system was developed that could quickly evaluate spray deposit distribution and coverage area on deposit collectors such as water sensitive paper or Kromekote^® card. The system is integrated with a handheld business card scanner, deposit collectors, a laptop computer, and a custom-designed software package entitled “DepositScan”. The software is composed of a set of custom plug-ins that are used by an image-processing program (ImageJ) to produce a number of measurements suitable for describing spray deposit distribution. The program worked with the handheld business card scanner to scan spray deposits on the collectors. After scanning the collectors, individual droplet sizes, their distributions, total droplet number, droplet density, amount of spray deposits, and percentage of spray coverage are displayed on the computer screen and saved in a spreadsheet. Spots smaller than 23.9 μm are ignored by DepositScan when 2400 dpi resolution was used. Observations of nominal size spots through a stereoscopic microscope verified the accuracy of the system, and demonstrated that because of pixel limitations, the accuracy of any image-processing program using the pixel recognition technique would decrease as the spot sizes decrease. The portable scanning system offers a convenient solution for on-the-spot evaluation of spray quality under various working conditions.     

Association of Mycobacterium avium subspecies paratuberculosis infection with milk production and calving interval in Iranian Holsteins

There are inconsistent results for the association of Mycobacterium avium subspecies paratuberculosis (MAP) infection with production and reproduction in dairy cows. Determination of these associations in each region is essential to encourage participation of dairy cattle producers in disease control programs. This study was conducted in Shiraz, southern Iran, to quantify the association of subclinical MAP infection with 305-day milk production and calving interval in Iranian Holsteins. A total of 21 dairy herds were selected for the study and in each herd, quarter milk samples were collected from ten to 12 dairy cows for PCR analysis. Data about parity, calving interval, length of lactation period, total milk production and 305-day milk production were also provided for each animal. Overall, 252 individual milk samples were collected. Herd- and individual-level prevalence of MAP infection were 23.8% (95% CI, 6.2–41.4%) and 3.2% (95% CI, 1.3–5.1%), respectively based on IS900 nested PCR. The results for 305-day milk production revealed a 248 kg reduction in positive cows compared with negative ones (P = 0.009). When cows from positive herds were compared with cows from negative herds, a 335-kg reduction in 305-day milk production (P = 0.005) and a 30-day increase in calving interval (P = 0.057) were observed in the former group. These findings support the previous results that paratuberculosis infection is negatively associated with the performance of the animals.     

Growth performance and plasma metabolites in juvenile Siberian sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> (Brandt, 1869) subjected to various feeding strategies at different sizes

The effect of various feeding strategies was evaluated on growth performance and biochemical parameters in two sizes of Siberian sturgeon (465.75?±?11.18 and 250.40?±?12 g) during 45 days. Fish were distributed into six experimental treatments including large fish with satiation feeding (LA), small fish with satiation feeding (SA), large fish with 50% satiation feeding (LR), small fish with 50% satiation feeding (SR), large starved fish (LS), and small starved fish (SS). Differences in final weight between LA and LR treatments were not noticeable, whereas SA and SR treatments showed significant differences. Growth parameters were more affected in small fish. In condition factor and weight gain in starved treatments, a considerable reduction occurred by interaction between feeding strategies and fish size, so the lowest values were obtained in SS treatment. Glucose levels significantly decreased in small fish during the starvation. Interaction between feeding strategy and fish size indicated the highest and lowest albumin level in SA and SS treatment, respectively. Cholesterol, triglyceride, total protein, and globulin showed no significant differences. It can be deduced that small fish are more sensitive to starvation than the large fish. Since glucose and albumin showed significant decrease in starved small fish, these parameters can help to monitor nutritional status and feeding practices. It was indicated that in both sizes of Siberian sturgeon, feeding 50% satiation reduced the food cost without negative impact on physiological condition, and it can be considered as an appropriate strategy to face unfavorable circumstances.     

The Potential of Green Manure Mixtures to Provide Nutrients to a Subsequent Lettuce Crop

The objectives of this greenhouse experiment were to quantify the benefits of green manure (GM) diversity and to assess effect of GM on a succeeding lettuce crop. Species included barley (B), field pea (P), sunn hemp (S), and buckwheat (U). Treatments included single plantings of B and P and mixtures of B and P (BP), B, P, and S (BPS), and B, P, S, and U (BPSU). The pea GM had the highest shoot concentration of potassium, calcium, magnesium, manganese, zinc, and iron. Roots had higher concentrations of nutrients than shoots. Accumulation of nutrients in legumes was higher than in barley. The CO₂ flux from the soil suggests that the most intensive mineralization period occurred within two weeks after incorporation of GMs. The mixtures and single planting of P mixtures had a significant benefit over single planting of B regarding fresh and dry weight of the lettuce.