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61.
The effects of wheat, potato, sunflower, and rape residues and calcite were evaluated in soil that received sodic water. These materials were added to a sandy‐loam soil at a rate of 5%, after which the treated soils were incubated for 1 month at field‐capacity moisture and a temperature of 25°C–30°C. Column leaching experiments using treated soils were then conducted under saturated conditions using water with three sodium‐adsorption ratios (SAR) (0, 10, 40) with a constant ionic strength (50 mmol L–1). The results indicated that the application of plant residues to soils caused an increase in cation‐exchange capacity and exchangeable cations. Leaching experiments indicated that the addition of plant amendments led to increased Na+ leaching and decrease in exchangeable‐sodium percentage (ESP). The ESP of the control soil, after leaching with solutions with an SAR of 10 and 40, increased significantly, but the level of sodification in soils treated with plant residue was lower. Such decreases of soil ESP were greatly affected by the type of plant residues, with the order of: potato‐treated soil > sunflower‐treated soil > rape‐treated soil > wheat‐treated soil > calcite‐treated soil > control soil.  相似文献   
62.
The biological effects of two important medicinal plants, Artemisia annua L. and Achillea millefolium (L.) (viz, mortality, growth, and feeding indices as well as enzyme and non-enzymatic activities) were studied on small white Pieris rapae L a deleterious pest of cruciferous plants under controlled conditions (16:8 h L:D at 25 ± 1 °C and 65 ± 5% RH). The LC50 and LC25 values were 9.387% and 3.645% for A. annua L. and 4.19% and 1.69% for A. millefolium (L.), respectively. At the lowest concentration (0.625%), the deterrency was 29.826% and 44.185% for A. annua L. and A. millefolium (L.), respectively. Feeding indices were variously affected with changes in a number of parameters and an increase in larval and pupal duration. The activity level of alkaline phosphatase increased sharply while alanin and aspartate aminotransferases showed a sharp decrease. For non-enzymatic compounds, the amount of glucose and uric acid increased, but total protein and cholesterol decreased. These results indicate that these two medicinal plants might possess potential secondary metabolites that may be useful for controlling potential insect pests.  相似文献   
63.
Laboratory and field experiments were conducted to determine the influence of different priming techniques on the germination characteristics and competition of weeds in sugar beet in 2008–2009. Three priming times and four priming methods were used in a laboratory study, and four priming treatments and four redroot pigweed densities (0, 4, 8 and 12 plants m?2) were used in a field study. Sugar beet seeds were treated with polyethylene glycol (PEG 8000), NaCl (1.5 N) and HCl (0.1 N) for 2, 4 and 6 h. Seed characteristics were significantly affected by HCl (0.1 N) treatment for 6 h. In this treatment, the germination percentage was 25 and 9% higher than control and NaCl (1.5 N) treatments after a similar time. An intermediate and low effect has been shown with NaCl (1.5 N) and PEG 8000 seed priming, respectively. Sugar beet root yield was reduced by 13, 54 and 89% compared with control treatment (without weed) at redroot pigweed densities of 4, 8 and 12 plants m?2, respectively. Sugar beet seeds primed with HCl (0.1 N) for 6 h gave a higher root yield than unprimed seeeds and the other primed seeds treatments. Overall, the results showed that weed control can significantly increase sugar beet yield and the seed priming technique can be used for weed control.  相似文献   
64.
Yield loss in potato damaged by hail is mainly caused by reduced leaf area and plant stand. A 2-year field experiment was conducted to investigate the effect of simulated hail damage on potato yield. The treatments were six levels of defoliation (control, 20, 40, 60, 80 and 100%) and five defoliation times (2, 5, 8, 11 and 14 weeks after emergence). The experiment was set up in a randomized block design with four replications, and the treatments were arranged as a factorial. From the perspective of yield loss, the most important time of defoliation, for mild and intense defoliation, respectively, were 8–11 and 5–11 weeks after emergence. The period between 5 and 8 weeks includes the stages of tuber initiation and tuber growth; the stages most sensitive to removal of aerial parts. Regardless of defoliation intensity, the production of small potatoes mostly occurred when defoliation occurred at 2 and 5 weeks. Plants were able to recover from any level of defoliation if it occurred at an early stage. In summary, yield reduction was little influenced by intensity of defoliation, but the timing of defoliation was evidently the most important factor.  相似文献   
65.
Spiny bollworm, Earias insulana Boisduval. (Lep.: Noctuidae), causes huge losses to cotton crops each year. As a relatively hardy species of insect, E. insulana tolerates a wide range of environmental conditions and so is prevalent in many regions of the world. Effect of sex pheromone traps to control spiny bollworm by mass trapping method was studied. Investigation of monthly changes in captures in relation to temperature carried out during 2012 in the Darab region of the Fars Province of Iran. The experiment was carried out in randomised complete blocks design with four treatments and four replications. The treatments used application of the sex pheromone trap at the rates of 16, 20, 24 and 30 traps/ha. The captured male moths were collected and counted every three days. Analysis of the variance of results showed significant differences between time and trap number in the trapping values of E. insulana. Moth populations were observed in the second week of September. The highest and lowest captured insects per hectare were 30 and 16 traps/ha, respectively. The peak captured E. insulana adult males in the sampling period was on 18 November. These results enable forecasting of seasonal E. insulana population peaks, providing additional information vital for the development of a successful, integrated pest-management programme for spiny bollworm.  相似文献   
66.
Thyme (Thymus vulgaris) is a subshrub from the lamiaceae family with plants that are rich in essential oils and antioxidative phenolic substances. The aim of the study was to investigate the effect of dietary thyme and fish oil supplementation on the semen characteristics of miniature Caspian horse. Sixteen stallions were randomly allocated into four groups and received four different diets: unsupplemented control diet, supplemented with fish oil at 2.5% dry matter intake (DMI), supplemented with fish oil (2.5% DMI), and thyme (0.02% DMI), and supplemented with thyme (0.02% DMI). All experimental diets were formulated according to National Research Council (1998). Semen was collected at 0, 30, 60, and 90 days. The semen samples were cooled and preserved at 5°C. Cooled diluted semen samples were evaluated in vitro by microscopic assessments of chilled sperm motility, acrosomal and other abnormalities (head, midpieces, and tail), viability (evaluated by Eosin–nigrosin), and plasma membrane integrity (evaluated by hypo osmolarity swelling test), and the level of malondialdehyde (MDA) was determined during cool storage 0, 24, and 48 hours after collection. The results showed that total and progressive sperm motility and plasma membrane integrity and functionality in all groups were significantly decreased with increasing storage time. On the other hand, the level of MDA in all groups was significantly increased with increasing storage time. Also, the results showed that most sperm quality parameters in this study were significantly higher in fish oil–thyme and fish oil group compared with thyme and control groups after 24 and 48 hours of storage at 5°C. We concluded that dietary supplementation of fish oil and thyme can improve sperm quality in miniature Caspian stallions during storage in cool condition via increasing total and progressive motility and plasma membrane integrity and functionality. More advances in vitro evaluations and artificial insemination are required to reveal the exact effects of thyme on miniature Caspian stallion sperm quality and its fertilizing ability.  相似文献   
67.
The content and fractionation of seven heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, and Zn) were determined in 28 surface soil samples (0–20 cm) of agricultural topsoil from Isfahan Province in central Iran. The order of abundance of metals in the soils was Fe (1240.4 mg kg?1) > Mn (95.7 mg kg?1) > Pb (51.6 mg kg?1) > Zn (23.8 mg kg?1) > Ni (13.4 mg kg?1) > Cu (7.0 mg kg?1) > Cd (2.8 mg kg?1). Iron, Mn, Ni, Pb, and Zn existed in paddy soils mainly in Fe-Mn oxides (53.6 %, 65.2 %, 40.4 %, 40.8 %, 53.3 %, respectively), whereas Cu and Cd occurred essentially as residual mineral phase (41.4 %) and carbonate (36.1 %), respectively. The mobile and bioavailable fractions of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in paddy soils averaged 48.8, 20.8, 0.79, 29.2, 28.5, 41.1, and 24.8 %, respectively, which suggests that the mobility and bioavailability of the seven metals probably decline in the following order: Cd > Pb > Mn ≥ Ni > Zn > Cu ? Fe, suggesting greater contribution of anthropogenic Cd. As Cd in soil is easily accumulated by plants through the root system, the concentration of Cd in these paddy soils could be a concern to human health.  相似文献   
68.
This study was conducted to evaluate possible alteration in the activity of arginase, an important enzyme of cell proliferation and vascular smooth muscle contraction regulator in diabetics, that may be correlated with low fertility in diabetic patients. In this investigation, 6 apparently healthy adult male dogs were selected and divided in two groups, diabetics and non-diabetics. Diabetes mellitus was induced in one group by intravenous (IV) injection of alloxan (100 mg/kg). Dogs with a fasting blood glucose (FBS) of more than 200 mg/dl were considered to be diabetic. Four weeks following induction of diabetes mellitus, the animals in both groups were anesthetized by an IV injection of sodium thiopental. Livers and whole reproductive systems, including the testes, penis, urethra, and prostate, were dissected. The epididymides, corpus cavernosum, corpus spongiosum, penile urethra, and vas deferens were also dissected and removed from the reproductive system. Arginase activity and total protein were measured by the urea and Lowry's methods respectively in above mentioned sections. Plasma testosterone was determined by the radioimmunoassay method. The results showed significantly (P<0.05) increased arginase specific activity (ASA) in the liver, epididymis, prostate, corpus cavernosum and corpus spongiosum of the diabetic dogs. In the reproductive system of the diabetic dog, the maximum and minimum ASA was seen in the corpus cavernosum and testes, respectively (105.12 +/- 8.76 vs. 25.0 +/- 0.55). No such variation was observed in the ASA of normal dogs (39.0 +/- 5.47 vs. 25.0 +/- 5.47). There was no significant difference in plasma testosterone level between the groups. In conclusion, diabetes increased the ASA in liver, prostate, epididymis, corpora cavernosa, and corpora spongiosum of the male dogs and may contribute to erectile dysfunction or low fertility in diabetics.  相似文献   
69.
Plasma chemistry, lipid metabolism and vitellogenin gene expression of captive Sterlet sturgeon Acipenser ruthenus were studied in different maturity stages. A total of 32 fish were sampled, and maturity stages were identified on the basis of histological criteria and direct observation. Females were classified to four groups: previtellogenic, vitellogenic, post-vitellogenic, and atresia. Blood, gonad and liver tissue samples were taken through non-lethal biopsy. Our results showed that plasma levels of glucose, cholesterol, triacylglycerol, high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, calcium, phosphorus, alkaline phosphatase activity, albumin and total protein increased during ovarian development and were highest at post-vitellogenic stage. The lowest amounts in atresia stage demonstrate that lipid and energy imbalance was related to reabsorption and digestion of the yolk. These results suggested that the VLDL was the main plasma lipoprotein component of Sterlet. We determined that lipoprotein lipase and hepatic lipase activity increased during vitellogenesis process which suggested the role of lipase enzymes in regulating blood lipid metabolism. RT-PCR analysis indicates that Vitellogenin (VTG) mRNA could be detected both in livers and ovaries of female Sterlet. Throughout the study, the expression level of VTG gene showed an increase both in ovaries and in livers reaching its peak at late vitellogenesis stage. This strongly indicated a relation between VTG mRNA and ovarian development.  相似文献   
70.
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