Iran Agricultural Research
Volume:31 Issue: 1, Summer and Autumn 2012

Measurement of soil saturated hydraulic conductivity, Ks, is normally affected by flow patterns such as macro pore; however, most current techniques do not differentiate flow types, causing major problems in describing water and chemical flows within the soil matrix. This study compares eight models for scaling Ks and predicted matrix and macro pore Ks, using a database composed of 50 datasets. The database includes data regarding Ks, soil bulk density, particle size distribution, with textures ranging from sandy loam to clay. The results showed that among the models tested, the Saxton and Kozeny Carman models performed best for estimating soil Ks using scaling techniques. In contrast, Campbell and Cosby models were not suitable for similar Ks scaling method. Generally, Saxton, Kozeny Carman, Poulsen Saxton, Vereecken, and the Brakensiek models gave the best estimation of soil Ks. Furthermore, all models had smaller estimation deviations for loam soils than for clay loam soils. The results also showed that a sample with the average characteristics of all samples should be taken as a reference point when scaling Ks is used. Overally, the Saxton and Kozeny Carman models are recommended for scaling Ks. The performance of a simple fractal model was not suitable neither for matrix nor for macro pore hydraulic conductivity.

In order to determine the responses of morphological characteristics, yield and yield components of rapeseed (Brassica napus L.) to plant density and weed interference duration, a factorial experiment was conducted using a randomized complete block design with 3 replications at the Rice Research Institute of Iran (RRII) in Rasht, in the 2008 growing season. The factors comprised plant density at 2 levels (80 and 57 plants m2) and weed interference duration at 7 levels (including weed competition with canola until the end of crop emergence, 2, 4, 8 leaf stages, and formation of flower buds). After the above mentioned growth stages, weeds of each treatment were removed manually until harvest. Two check treatments including weedy and weed free were also selected as control. The traits evaluated in this research were plant height, number of secondary branches plant1, height of the lowest pod bearing branch, pod length, pod number plant1, grain number pod1, 1000 grain weight and grain yield. The results indicated that plant density, weed interference duration and their interaction had significant effects on all traits except pod length. In addition, the 1000 seed weight showed significant response to separate effect of each factor, but was not influenced by their interaction. The highest value of grain yield was related to a density of 80 plants m2 on total weed free check (full season weed free) and the lowest value of this trait was obtained from a density of 57 plants m2 on weedy check (fullseason weed infested) treatment.

The present study examined the effects of Vitacel raw fiber on great sturgeon (Huso huso) immunocompetent cell population size including lymphocyte and neutrophil populations and lysozyme activity after oral administration of the feed and Vitacel at 1.3% of the feed for 90 days. Generally, a significant increase was seen in the neutrophil count of fish receiving Vitacel as compared to the control group 90 days post treatment (P<0.05). Also, lysozyme activity in fish that received Vitacel was significantly higher than the control group 90 days post treatment (P<0.05). The results suggest that Vitacel may effectively promote immune responses in great sturgeon (Huso huso).

During the years 2007 and 2008, samples of winter jasmine (Jasminum nudiflorum) with symptoms of galls on shoots were collected from Shiraz, Fars province, Iran. Gram and oxidase negative, aerobic bacterium that produced fluorescent pigment on Kingۥs B medium was isolated from galls of infected trees. All isolates produced a hypersensitive reaction in tobacco. They were negative in arginine dihydrolase, gelatin hydrolysis, and potato rot slices. The strains were catalase positive, produced H2S from cysteine and were able to grow at 37ْ C. Isolates were variable in levan production. All of the isolates were identified as Pseudomonas savastanoi based on morphological, physiological and biochemical characteristics, pathogenicity and with specific primer pairs iaaLf and iaaLr. In addition, the bacterium was detected directly by PCR in the gall from naturally infected winter jasmine plants.

The aim of this study was to determine the most suitable shaking frequency and amplitude for shake harvesting Esfahan''s edible fig (Ficus carica cv. Sabz). A hand held limb shaker with adjustable shaking frequency and amplitude was used for this study. A 3x3 factorial experiment with three levels of oscillating frequency (10, 12 and 14 Hz) and three levels of shaking amplitude (20, 32.5 and 45 mm) was conducted to investigate the effects of shaking frequency and amplitude on fruit detachment. Analysis of variance and mean comparison of fruit detachment data showed that the effects of shaking amplitude and shaking frequency on fruit detachment were significant. The percentage of unripe fruit detachment significantly increased at higher levels of shaking amplitude and frequency. Complete ripe fruit detachment (100%) and relatively high unripe fruit detachment (16.9%) was obtained at a shaking amplitude of 45 mm and frequency of 14 Hz, but a shaking amplitude of 45 mm and shaking frequency of 10 Hz with high ripe fruit detachment (93.3%) and acceptable unripe fruit detachment (9.4%) is recommended. Harvesting rate during 5s of shaking was measured which showed that the optimum time needed to harvest a limb is only 4s. Comparison of mean values of cumulative fruit removal of 60% (T60) and 90% (T90) at frequency amplitude combinations indicated that the shaking duration necessary for 60% and 90% fruit removal both followed a decreasing trend by increasing the shaking amplitude and frequency. This study suggests the feasibility of utilizing limb shakers as a practical approach for selective harvesting of ripe fruits.

In recent years, several oconjugation protocols have been developed to improve the functional properties of the enzyme lysozyme. In this study, the optimum conditions of lysozyme – oxidized inulin conjugation and functional properties of the modified lysozyme were investigated. Initially, inulin (MW about 25 kDa) was oxidized by periodate to provide the reactive carbonyl groups to attach to amino groups of lysozyme for Maillard reaction and was then conjugated to the enzyme at a molar ratio of oxidized inulin to enzyme of 5:1. A number of studies were conducted to investigate the optimization of lysozyme – Inulin conjugation consisting of different pH levels (3, 7, and 9), different temperatures (40, 60, and 80°C), and different reaction times. The degree of modification was determined by SDS-PAGE and sugar analysis of the product. The best condition for conjugation was determined to be 60°C at pH 7.0 for one week. The results showed that under these conditions, the inulin-lysozyme conjugate had 58% of the lytic activity of the native enzyme and had better emulsifying properties and heat stability than native lysozyme. Moreover, there was significantly higher protein solubility at pH 7.0 and 9.0 at different temperatures than heated lysozyme. Taken together, the results of this study indicated that lysozyme modification by oxidized inulin results in a new product with improved functional properties which may be employed for different industrial purposes.