Analysis of spatial and temporal risk of agricultural loss due to flooding in paddy farms

Evaluating agricultural loss due to flooding is essential for defining an appropriate risk level in flood management projects. This research introduces a method for computing annual damage risk for rice fields with respect to both spatial and temporal pattern of floods, while considering the effect of crop growth stages on the total damage. For finding the spatial pattern of floods, HEC-RAS was employed to derive selected physical parameters of floods of interest and then a physical loss function was used to calculate the unconditional loss over flood prone areas. A time-dependent loss function was introduced for rice to determine the effect of growth on damages derived through the physical loss function. Due to the seasonal nature of agricultural risk, frequency analysis was performed for seasonal discharges for each growth stage of rice. A method was introduced to use the concept of Expected Annual Damage in agricultural fields. A method called “AGEAD” was introduced for evaluating short-term risk for agricultural activities considering their inherent spatial and temporal characteristics. Results showed that damages evaluated by employing AGEAD were completely different from what was obtained by applying a flood of defined return period, i.e. from the results of long-term risk evaluation. While it is common to attribute a unique predicted loss to all flood prone areas, AGEAD application showed that different zones in flooded paddy fields were subjected to different amount of damages from 100 to 0%.     

Investigation formaize inbred lines resistance to <Emphasis Type="Italic">Maize Rough Dwarf Virus</Emphasis>(MRDV)

Maize rough dwarf virus (MRDV) is the most important disease affecting maize growth in Iran. In the present study, the putative resistance capacity of 35 maize inbred lines against the causal agents of MRDVwas studied under natural field infection in 2010 and 2011. The viral transmitter was a plant hopper known as Laodelphax steriatellus. Early sowing provided suitable temperatures for vector propagation and transmission and therefore natural infection under field conditions. Sowing single rows of SC704 as vector spreader between every five rows of inbred lines caused adequate vector propagation and viral transmission. This shows that viral infection was sufficient and possible resistance was linked to viral resistance, not failure, in vector transmission. In principal component biplot, plant height vector had wide angles with the vectors for disease severity index and MRDV incidence that showed the negative association of plant height with MRDV disease. The percentage of natural infection to MRDV in susceptible control(SC704) was about 64%. The genotypes A679, K3547/3, K3545/6, K3653/2, and B84 were more susceptible to MRDV. Only the line K3640/3 had low disease incidence and severity and it can be considered as resistant for possible use in genetic studies. Results showed that an early sowing of maize in temperate regions increases the chance of transmitting viruses via their vector.     

Ileal relaxation induced by Mentha longifolia (L.) leaf extract in rat

The effect of Mentha longifolia (L.) leaf hydroalcoholic extract (MLE) was examined on rat ileal smooth muscle contractions. Last portion of ileum from male adult Wistar rat was mounted in an organ bath containing Tyrode solution. The tissue was contracted by carbachol (CCh, 10 microM), KCl (60 mM) and BaC12 (4 mM) and then MLE (0.0625-1 mg mL(-1)) was added to the bath cumulatively. The effect of MLE on KCl-induced contraction was examined after tissue incubation with propranolol (1 microM), naloxone (1 microM) and N omega-nitro-L-arginine methyl ester (L-NAME, 100 microM). The effect of MLE on CaCl2-induced ileal contraction in Ca(2+)-free with high potassium Tyrode solution was also evaluated. The role of potassium channels was examined by ileum incubation (5 mim) with tetraethylammonium (TEA, 1 mM). The results showed that KCl-, CCh and BaCl2-induced ileal contractions were inhibited (p < 0.001) by cumulative concentrations of MLE with the same potency. In addition, MLE (0.25-1 mg mL(-1)) inhibited (p < 0.01) ileal contractions induced by CaCl2 (0.45-2.7 mM) in a concentration-related manner. The antispasmodic effect of MLE was affected neither by propranolol, L-NAME nor by naloxone. The MLE concentration-response curve was shifted to the right (p < 0.05) by tissue incubation with TEA. From results it may be suggested that Mentha longifolia hydroalcoholic leaf extract induces its spasmolytic activity mainly through disturbance in calcium mobilization and partly by potassium channels activation. Present results show that Mentha longifolia leaf extract exerts relaxant effects on intestinal smooth muscle, consistent with the traditional use of the plant to treat gastrointestinal disorders such as diarrhea and colic.     

森林生态蓄水功能的经济评价(个案研究:伊朗扎格罗斯森林)(英文)

森林生态服务直接或间接地造福人类。本文利用模拟模型和地理信息系统作为工具,分析生态因子对生态系统服务功能的作用,评估了伊朗西部扎格罗斯森林对Bazoft河流域水源保护的经济价值。应用HEC-HMS模型中的曲线数字法对降雨量-径流进行了模拟。该模型需要输入土地覆被、土壤、短期降雨和流出数据。用观测数据并分阶段校对对拟合模型的功效进行了修订。测定了森林在4种设定的土地覆盖方案中保水性和减少地表径流量的作用以及土地用途改变对该区降雨量-径流行为的影响。结果表明:方案一假定该流域全被森林覆盖,总的流出量将最小,降雨初期损失将增加。用重置成本法估算了森林水文功能之保水性经济价值。评估结果表明,每公顷Bazoft河流域的森林可以蓄存84.8立方米水,年产值0.5 US$/m3。因此,每公顷BazoR河流域的森林保水性经济评价值是43US$。说明覆被森林有利于该流域经济发展,该研究有助于决策者选择适当的、经济可行的发展策略。     

Salinity stress on various physiological and biochemical attributes of two distinct maize (Zea mays L.) genotypes

Present study investigates the effect of salinity stress on physiological and biochemical characteristics of two maize genotypes cultivated under controlled growth conditions. The selected maize genotypes being salt-tolerant and salt-sensitive were respectively designated as Sahwal-2002 and Sadaf. The experiment was conducted in triplicates, two varieties, three priming treatments and two salinity levels, in the Government College University, Faisalabad. The antioxidants activity was measured by comparing the tolerance in response to acute and prolonged salinity treatment. The difference of genotype with salinity tolerance as well as seed priming with phenylalanine were not dependent on antioxidant activity when salt exposure was prolonged. The results show that an indirect relationship was present for PAL seed priming and oxidative damage due to salt. The antioxidant enzymes present in plant effectively reduced the oxidative damage of salt and thus, increased the overall crop yield.     

Seed retention of ten common weed species at oat harvest reveals the potential for harvest weed seed control

We assessed the seed production and shedding pattern of 10 common weed species in two oat fields in Denmark. The aim was to evaluate the possibility of harvesting retained seeds on weeds at crop harvest by a combine harvester based on estimation of weed seed retention. Before flowering, ten plants of each weed species were selected and surrounded by a seed trap comprising of a porous net. When the plants started shedding seeds, the seeds were collected from the traps and counted weekly until oat harvest. Just before oat harvest, the retained seeds on the plants were counted and the ratio of harvestable seeds and shed seeds during the growing season was determined. The seed production and shedding patterns varied between the 2 years. Across both years, Anagallis arvensis L., Capsella bursa-pastoris L. Medik, Chenopodium album L., Geranium molle L., Persicaria maculosa Gray, Polygonum aviculare L., Silene noctiflora L., Sonchus arvensis L., Veronica persica Poir. and Viola arvensis Murray retained on average 61.6%, 52.7%, 67.2%, 58.4%, 32.05%, 59.5%, 95.7%, 23.5%, 51.7% and 33.9%, respectively, of their produced seeds at crop harvest. Silene noctiflora was classified as a good target for harvest weed seed control; C. bursa-pastoris, C. album, G. molle, P. maculosa, S. arvensis and V. arvensis were classified as intermediate targets; and A. arvensis, P. aviculare and V. persica were classified as poor targets.     

Plasma and urine pharmacokinetics of intravenously administered flunixin in greyhound dogs

Medication control in greyhound racing requires information from administration studies that measure drug levels in the urine as well as plasma, with time points that extend into the terminal phase of excretion. To characterize the plasma and the urinary pharmacokinetics of flunixin and enable regulatory advice for greyhound racing in respect of both medication and residue control limits, flunixin meglumine was administered intravenously on one occasion to six different greyhounds at the label dose of 1 mg/kg and the levels of flunixin were measured in plasma for up to 96 hr and in urine for up to 120 hr. Using the standard methodology for medication control, the irrelevant plasma concentration was determined as 1 ng/ml and the irrelevant urine concentration was determined as 30 ng/ml. This information can be used by regulators to determine a screening limit, detection time and a residue limit. The greyhounds with the highest average urine pH had far greater flunixin exposure compared with the greyhounds that had the lowest. This is entirely consistent with the extent of ionization predicted by the Henderson–Hasselbalch equation. This variability in the urine pharmacokinetics reduces with time, and at 72 hr postadministration, in the terminal phase, the variability in urine and plasma flunixin concentrations are similar and should not affect medication control.     

Development of a Brucella suis specific hybridisation probe and PCR which distinguishes B. suis from Brucella abortus.

A genomic library was prepared from Brucella suis DNA (MboI digested) and cloned into the BamHI site of pUC18. Colony hybridisation using a probe prepared from purified B. suis DNA labelled with alpha 32P was carried out to identify colonies of interest. About 20 colonies, which gave an intense signal upon hybridisation with whole B. suis genomic DNA as a probe, were selected. Because of the high degree of DNA homology between B. suis and Brucella abortus, a short probe was chosen as it would more likely give species specificity. Of seven fragments selected to probe whole B. suis, B. abortus, and Yersinia enterocolitica DNA, one was found to hybridise with B. suis only. The probe was sequenced in two directions and sense and anti sense primers of 25bp in length were chosen to yield a product of 421bp. After optimisation of the PCR, a product of 420bp was obtained with B. suis template DNA and two bands of 420 and 650bp were detected with B. abortus template DNA. This is the first reported PCR of the Brucella genome where a single pair of primers will discriminate between B. suis and B. abortus. No band was observed when the two primers were used to amplify E. coli, Y. enterocolitica, Enterobacter cloacae, Staphylococcus aureus, Streptococcus uberis, Corynebacterium bovis, or Serratia marcescens template DNA.     

Effect of growth regulators and explant on plant regeneration of Solanum lycopersicum L. var. cerasiforme

Tomato serves as a model to introduce agronomically important genes into dicotyledonous crop plants and to develop edible vaccines and produce cost-effective therapeutics. This study has developed an efficient protocol of shoot organogenesis for Lycopersicon esculentum Mill. through using of different types of explants and growth regulators. Generally, all explants responded significantly to presence of BAP. Best shoot regeneration for leaf (100%) was achieved on MS supplemented with BAP (2 mg/L) + IAA (0.1 mg/L), whereas it was recorded on MS supplemented with BAP (2 mg/L) and BAP (2 mg/L) + IAA (0.5 mg/L) for cotyledons (95%). In addition, hypocotyls (77%) showed the best shoot response on MS supplemented BAP (3 mg/L). Highest number of shoots per explant was 13.33, 12.25, 7.94 respectively for hypocotyls, leaves, cotyledons. The best medium for highest length of shoot was in the presence of BAP (3 and 2 mg/L) + IAA (0.1 mg/L) respectively for hypocotyl (45 mm) and leaf (40.50 mm) explants. This parameter was achieved for cotyledons (13.32 and 12.5 mm) on MS medium supplemented with BAP (3 and 2) mg/L + IAA (0.1 mg/L), respectively. The increasing of BAP concentration up to 3 (mg/L) causes shoot length to continue developing, but it fell down in the presence of BAP (4 mg/L) due to the toxic effect of growth regulators accumulation. Root formation took place within 10–14 days after culturing on the rooting media. Best root induction (100%) was observed on MS medium supplemented with IAA (0.1 and 0.2 mg/L). All rooted shoots acclimated in phytotron and then cultivated in the greenhouse.