PLANT AND ECOSYSTEM
Year:2006 | Volume:2 | Issue:8|Papers Count:9

Pesticides are essential in agricultural practices but due to their biocidal activity and potential risk to consumer, the control of pesticide residues in foods is The major source of concern for the population. This paper is conducted to evaluate tetradifon, deltametrin, and pymetrozin pesticide residues on cucumbers. For this purpose cucumber samples from 6 sites were collected after application of pesticides emulusions in autumn 1380 and summer 1381. In lab, the cucumber samples were analysed for the 3 pesticides by gas chromatography. The results showed that concentrations of pymetrozin and tetradifon pesticides in the collected cucumber samples of some sites were above the MRLs (maximum residue level). The results of Duncan s multiple range comparsions showed that, pymethrozin residue had significant differences (0.05) in Absard and Damavand road sites in summer and autumn.Advantages of the application of pesticides in agriculture in producing better crops must be weighed against the possible health hazard arising from the toxic pesticide residues in food.

In this study 35 Rosa damascena Mill. Genotypes was evaluated based on flower yield and components phenological and morphological characteristics. The trial was carried out in the fields of Fadak Botanical Garden in Dezful (affiliated to Research Institute of Forest and Rengelands) Iran. The experiment was conducted under design in randomized complete blocksdesign with three replicates during 2005-2006. Genotypes showed significant differences for flower number, per plant, flower number per m2 flower yield per plant petal number flower fresh weight flower dry weight flower diameter plant height canopy leaflet area leaflet fresh weight leaflet dry weight and leaflet area/weight ratio (P<0.01), and flower dry matter percentage (P<0.05). The comparison of means was done using Duncan s test. The Comparison classified the genotypes in different groups. In correlation analysis showed significant relations between traits important in genotypes (P<0.01), positively correlated (r=0.97) flower yield with flower number per plant, flower number per plant with flower number m2 (r=1.00) and plant height with canopy (r=0.67). The evaluation from obtained results showed variety in flower yield and components between genotypes exsiting in country. The measure flower yield per plant and flower number per plant in the study showed positive correlation and relative significant. It can be used as important traits in evaluation of criterions and selection of genotypes.

In order to study the effect of water deficit on drought resistance indices of Brassica napus cultivars. (an experiment was carried out in split plot design on the basis of randomized complete block design with 4 replications. Irrigation at two level normal irrigation (after 80 mm evaporated water from class A evaporation pan) and deficit irrigation (stop irrigation after steam elongation stage) as main factor and Rapeseed cultivars at 10 levels include: Hyola 401, Option 500, Hyola 308 Quantum, Eagle, Comet, Amica, Goliath, Heros, Sarigol was considered as sub factor.The average amount of two years seed yield showed that Heros with 4013.5 Kg/ha, Goliath with 3916.0 Kg/ha, comet with 3812.0 kg/ha, and Hayola 401, with 3793.0 Kg/ha, had maximum amount of seed yield in water deficit condition and Amica with 5348.0 kg/ha, Hyola 401 with 5035.0 kg/h had maximum amount of seed yield in non water deficit condition.The result of compairing average amount of seed yield cultivars Comet with 0.4011, Heros with 0.4076, Quantum with 0.4815 and Eagle with 0.6886 showed minimum amount of Stress Susceptibility Index (SSI) and maximum amount of Ralative stress tolerance Index (Tol) belong to Amica with 1565.0 kg/ha, Hyola 401 with 1241.5 and Option 500 with 1116.5 kg/ha. Results of mean productivity (MP) shwoed that Maximum amount of this Index with 782.50, 620.75 and 577.75 Kg/ha belongs to Amica Hyola 408 Option500 and Sarigol the result of this experiment showed complete similarity and correlation between Geometric Mean Productivity (GMP) and Stress Tolerance Index (STI) for screening high seed yield in water deficit and non - water deficit conditions.Maximum amount of GMP and STI belongs to Amica with 4497.942 and 1.10152, Hyola 401 with 4370.386 and 0.9584, Goliant with 4361.97 and 0.8755 and minimum amounts of them obtained from Option 500 with 3732.230, 0.6989. and Hyola 308 with 3429.362 and 0.5901.Therefor SSI was not suitable for screening cultivars with high amounts of seed yield in water and non water deficit. MP and Tol Indices interuduced Cultivars with high seed yield in non water deficit condition successfully. And GMP and STI Indexes had maximum efficiency for selection of caltivars which had maximum seed yield in both conditions, water deficit and non -water deficit.

A pot experiment was conducted for the study of the effects of NaCl on the accumulation of some mineral and organic matter in Dill (Anethum graveolens L.). A completely randomized design was arranged with five salinity levels (0, 25, 50, 75 and 100 mM. NaCl) and four replications. Seed culturing was done in greenhouse and Plants irrigation with the help of Hoagland nutrition solution. Total dry weight stem and root length total leaf chlorophyll, total soluble sugar and Na+ K+ and Cl- were measured at the final leaf growth stage. Results showed that total chlorophyll, dry weight K+ in leaves, stem and root length significantly decreased with increasing salinity levels, while total soluble sugar increased. In addition the significant increase of Na+ and Cl- accumulation in the leaves Particularly at high Salinity levels lead to nutrient deficiency and ionic toxicity.

Mycorrhizal colonization improve and increase the uptake of nutrients. In this research the effect of VAM (Vesicular- Arbuscular mycorrhiza) colonization on uptake of potassium and magnesium was studied. In this experiment natural soil containing spores of Glomus spp was used. Mycorrhizal spores were exposed to 4 concentrations of K solution i. e. 240 (soil K content) 360 and 480 mg/L and 3 concentrations of Mg i.e. 4.8 (soil Mg content), 7.2 and 9.6 meq/L concurrently. Plants were watered every 4 days for 16 days with 50 ml distilled water. A pot with sterilized soil was used as negative control. To study the mycorrhizal colonization very thin longitudinal sections of plant roots (>1mm in diam.) were prepared manually and stained with lactophenol-cottonblue. Mycorrhizal percentage was determined by the grid-line intersect method.To measure Mg and K content atomic absorption method has been used. Mycorrhizal colonization increased Mg uptake but decreased K uptake. The maximum Mg content and minimum K content were observed in root and shoot when K (360 mg/L) and Mg (7.2 meq/L) were added to the pots concurrently. Regarding to interaction between VAM and these elements by regulation of Mg and K in rhizosphere would increase mycorrhizal colonization in plants can be increased and through this way plant nutrient status aiming resistance against stresses of environment can be changed.

In order to study the effect of deficit irrigation, estimate of yield function, improvement of water use efficiency and obtain the optimum yield of cotton, an experiment based on Randomized Complete Block Design (RCBD) consist of 6 water treatments with 4 replicates on cotton (Sahel var) was conducted in Baye Kola Agricultural Research Station in Mazndaran Province for 2 years (2002, 2003). Analysis of variance and comparing 2 years experiments showed that the effect of irrigation treatment on cotton yield at 1% probability level was significant. The irrigation treatments were conducted based on 0, 25, 50, 75, 100 and 125 percent of water requirements. Io treatment (zero percent of water requirement) and I3 (75% of water requirement) with the 1679 and 3099 Kg/ha yield had the minimum and maximum yield respectively. However water use efficiency in Io and I1 treatments were the maximum values. It is observed that in I3 treatment with 25% reduction of water requirement there is no yield reduction and in I2 treatment with 50% water requirement reduction (comparing with perfect water use I4 treatment) about 15% yield reduction was obtained. According to the results of this research it is not necessary to irrigate the cotton with perfect water requirement and 50% of water requirement is sufficient.

Dearth of water content in soil erosion of water and soil and destruction of soil structure are the major problems of shires of Iran. These are the results of perfect and strong plow of soil. In this study, tillage systems such as Conventional tillage, Reduced tillage and Minimum tillage compared and evaluated from the stand points of yield component (uniform surface and vertical seed distribution, percentage and velocity of emergence), Com Index and Field Capacity. The statistical design is Randomized Complete Block design with four replicates.Analysis of com index numbers in depth of 5 cm showed significant difference so the maximum value of com index was for reduced tillage treatment and the minimum value was for the other treatments. Also, Analysis of com index numbers in depths of 10 & 20 cm showed significant difference at level of 1%, so the minimum value of com index was for conventional tillage treatment and the maximum value was for the other treatments. Analysis of the horizontal and vertical seed distribution and velocity of emergence factors, showed no significant difference. At the stand points of percentage of emergence there was significant difference at level of 5%, so the maximum value was for minimum tillage treatment. At the stand points of required time of preparation of seed bed in hectare, minimum and maximum time were for minimum tillage treatment (4.5 hours) and conventional tillage treatment (7.5 hours), respectively.Accordingly the most suitable of tillage system is minimum tillage system, because of excluding above analysis, it could be indicated to high traffic of conventional tillage system in farm!

In order to determine physiological differentiations of the spring safflower genotypes a trial was conducted in Karaj Research Institute for Seed and Plant improvement in 2003. In this experiment 7 safflower varieties and lines were compared in a randomized complete Block Design with four replications. Some important traits such as: biomass harvest index, day to booting, day to flowering, day to 50% of flowering and day to maturity were recorded during the growth period. Statistical analysis (ANOVA)shown minimum of day to 50% of flowering day to end of flowering and day to maturity 68 83 and 102 days related to I.L.111 respectively. The maximum of biomass related to I.L.111 to 59.8 g/plant and high rate of harvest index to 28.5% related to I.L.111. As a conclusion the new and advanced line (I.L.111) can be introduced for Karaj and similar regions, as suitable and new spring safflower variety.