JWSS - Journal of Water and Soil Science

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To carry out this study, total DNA was extracted from eggs and from second stage juveniles of several populations of Meloidogyne javanica and Meloidogyne incognita, using phenol / chloroform method. Following extraction, DNA was electrophoresed on 1% agarose gel to determine its quality and quantity. A specific primer pair (C₂F₃ / 1108 23 and 20 nucleotides, respectively) was used to discriminate M. javanica from M. incognita populations using polymerase chain reaction (PCR). Primer annealing sites were located in the 3′ portion of mitochondrial gene encoding cytochrome oxidase subunit II (COII) and in the 16S rRNA gene. Following PCR amplification, electrophoresis of amplified DNA showed 1.7 kb fragment in populations of both species. Digestion of 1.7 kb amplified product with HinfI restriction endonuclease resulted in the generation of two DNA fragments of 0.7 and 1.0 kb in M. javanica and three DNA fragments of 0.3, 0.4 and 1.0 kb in M. incognita. There were no differences in the digestion patterns among various populations of each species examined.

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Northern watershed of Kouhrang River with the area of 68437 hectares is located in northwestern Chahar Mahal and Bakhtiary province within 49ْ 54ً to 50ْ 9ً E longitude and 32ْ 83ً to 32ْ 36ً N latitude.Making a balance and equilibrium between the number of ranchers, the rangeland production potential and appropriate flock size in each utilization unit is a necessary task. It is a matter of importance to determine suitable ranch size based on pastoral household but suitable household livelihood as well. The main goal of this study is to determine utilization unit size based on ecologic and socioeconomic factors for each household. Along with detecting the ranch allotments, the range capacity and its productivity potential were studied. Then, based on expenses and the revenues resulting from herdship,(on ranges), the suitable flock size for fulfillment of the household expenses regarding the range utilization periods, the suitable range size per household was determined. 10 vegetation types with 0.91 AUM per hectares grazing capacity were detected in studied area. There are 46 range allotments and some parts of other 6 range allotments in studied area with average area at 1510 hectares. Average pastoral household is 36.8 per unit range allotments. Pastoral households share at rangelands is 41 hectares now. The minimum and suitable ranch area for each pastoral household which can provide annual needs and costs is 520 hectares and 142 animal unit at a mix flock at 3 to 2 ratio of sheep to goat for a 100 – dayes grazing season. The result of this study showed that production potential at each range unit is influenced by flock size, household share on farming lands, and the household numbers on each ranch unit. Ranch unit and the livelihood level, have significant influence at 5% level on suitable ranch size per household.

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  A labyrinth spillway is an overflow spillway to regulate and control flow in canals, rivers and reservoirs. The main hypothesis for the development of such a spillway is to increase the discharge per unit width of structure for a given headwater. This type of structure is often an efficient alternative to a gated-spillway type where either the increase of the flood-passage capacity or the control of the water surface upstream is concerned. This study was aimed to investigate the hydraulic performance of labyrinth spillways of general trapezoidal planform with simple curved apexes. In the experimental work, twelve spillway models with double cycles were considered using three different curved apexes (R/w= 0.15, 0.2, 0.25), each with four different crest heights (w/P= 1.5, 2, 3, 4). Based on the cited recommendations, the length magnification was set to a constant ratio of (l/w= 3) the crest shape was to be of a semi-circular form with simple radius (r= 15 mm) and the spillway walls were vertical with the thickness of T= 2r. An intensive experiment was carried out over a wide range of flows, providing 720 flow data ranging from free flow to submerged flow conditions. 1D flow equation was presented using combined mathematical and dimensional analysis. A coefficient of discharge, C_d, was introduced to represent the influence of the effective geometric and hydraulic parameters on the flow capacity over the spillway. Modular limit was also controlled to see whether the flow over the spillway would be submerged. The results of the study indicate that the modified curved planform of the spillway apexes with consistent divergence in the downstream channel introduces a significant improvement in the flow efficiency over the labyrinth spillways. Spillways with narrower curved apexes (i.e. R/w≤ 0.2), and with the vertical-aspect ratio of (2≤w/P<3) provide more stable and higher hydraulic performance than any other labyrinth planforms over a wide range of flows (i.e. 0.10/P<0.6). In terms of the flow capacity, the proposed spillway model is shown to be more efficient than other zig-zag planforms (i.e. triangular and trapezoidal shapes) with an identical crest length.

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One of the properties of systemically acquired resistance in plants is their concomitance with the biochemical changes including enhancement of activities of defense-related enzymes. The leaf extract of Reynoutria sachalinensis (F. Schmidt) Nakai is known to be an effective compound for the control of a few plant diseases particularly powdery mildew of cucurbits (caused by fungal pathogen Podosphaera fusca), by inducing host defense responses. In the present investigation, the effects of this extract on some defense responses of cucumber plants were studied via in vivo tests. Changes of defense responses in the extract treated-cucumber plants, with or without pathogen inoculation, were studied and compared with those of non-treated control plants. Results indicated that specific activity of peroxidase increased significantly in treated tissues. Enhancement of enzyme activity showed the same patterns in both the pathogen inoculated- and non-inoculated-plants thus the pathogen attack did not affect the enzyme activity. Specific activity of phenylalanine ammonia-lyase in the non-inoculated extract treated-plants showed a transient fast increase during 24 hours after the treatment, whereas in the inoculated ones, it showed a permanent slow increase probably due to the interaction between extract treatment and pathogen attack. Phenolic content of extract treated-plant tissues, despite small fluctuations, did not show any definite pattern of changes.