PLANT AND ECOSYSTEM
Year:2008 | Volume:3 | Issue:12|Papers Count:8

Many investigations concerning the residue of insecticides on foodstuff have been conducted in the developed countries during the last two decades, but unfortunately in our country, despite consumption of insecticides, there have only a few studies on this field. In most rice fields in mazandaran Province, Diazinon is applied to control Chilo suppressalis. Taking into consideration the application of these insecticides in the rice fields in the north region of our country, this investigation was carried out on the rice plant and rice granules in order to get the necessary information from the concentration of insecticides residual, when the rice consumed, 125 samples were provided in 5 areas of Amol county in 2007. The results showed Diazinon in the sampling stations 1 and 4 until 2 weeks after poisaning and in station 2 and 3 until one month after poisoning and in station 5 until Second month after application. The greatest amount of Diazinon poisons in station 1 was 1.14 ppm.This study cleared that the physical and chemical properties of the studied insecticides, such as fumigation quality, ecological conditions and type of soil, caused the decrease and finally disappearence of insecticides during the period of plant growth.

According to the conducted samplings through 1997-2006 in different regions of Golestan province on the base of collecting the whiteflies’ pupae (Homoptera: Aleyrodidae) from the host plants, 24 species including, Acaudaleyrodes rachipora Singh, Aleurocanthus woglumi Ashby, Aleurocanthus zizyphi Priesner & Hosny, Aleurolobus marlatti Quaintance, Aleurolobus moundi David & Subramaniam, Aleurolobus selangorensis Corbett, Aleurotrixus floccosus Maskell, Aleyrodes proletella Linnaeus, Aleyrodes singularis Danzig, Bemisia afer Priesner & Hosny, Bemisia confusa Danzig, Bemisia mesasiatica Danzig, Bemisia salicaria Danzig, Bemisia silvatica Danzig, Bemisia tabaci Gennadius, Bulgarialeurodes cotesii Maskell, Dialeurolobus rhamni Bink-Moenen, Paraleyrodes minei Iaccarino, Siphoninus phillyreae Haliday, Trialeurodes abutiloneus Haldeman, Trialeurodes packardi Morrill, Trialeurodes ricini Misra, Trialeurodes vaporariorum Westwood, and Trialeurodes variabilis Quaintance were determined. The identified aleyrodids belong to 11 genera, 5 tribes, and two subfamilies including, Aleyrodinae and Aleyrodicinae. Among the identified specimens, 2 genera including, Aleurotrixus Quaintance & Baker and Paraleyrodes Quaintance together with 4 species including, A. floccosus, D. rhamni, P. minei, and T. abutiloneus are newly recorded from Iran.

Heavy metals can be absorbed in marine sediment, and damaged marine ecosystem in a long time, therefore, it is necessary to measure amount in different times.Their Accordingly, the present study determined the concentration of Cu, Pb, Zn, Mn, Fe, Ca and O.M (Organic Matter) in a sediment core from Costal line of Boshehr in Persian Gulf.At first, the particles which are smaller than 63 microns were seprated and dried at 700c for 24 hours, then digested with the mixture of three solutions of HNO3, HCl & HclO4.Concentrations of heavy metals were determined by Atomic Absorbtion machine, and the results showed that the mean of Pb, Ni and Ca concentration is higher than the sediments of the world and the crust of the Earth.The mean of Cu, Zn, Mn, Fe & Al concentration is lower than the standard.The High amount of Ca is related to geological characteristics of the area. O.M has high amount at this area, and the results showed that the organic matters possess little amount of lithogenic source. The results showed that sediments of Persian Gulf were polluted by Pb & Ni when they were sampled in 2000.

In order to study the effect of base nitrogen levels on yield components of Rapeseed cultiva experiment carried out in factorial design on the base of randomized complete blocks with 4 replications from 2003 to 2005 that base nitrogen fertilizer was at 3 levels (0, 50 and 100 Kg/ha pure nitrogen) and Rapeseed cultivars at 6 levels Talaye, SLM046, Okapi, Regent*Cobra, Licord and Orient considered.Multiple variance analysis for 2 years showed that the effect of base nitrogen, cultivars and interaction effect between base nitrogen and cultivars on pods per plant, seed number per pod and 1000 seed weight had significant effect and the effect of base nitrogen on seed number per pod did not show any difference at 5% level.The compairing results of two years examination showed that after base nitrogen increased to 100Kh/ha, the average amount of pod number per each plant increased to 109.9 and cultivar regent*cobra with 132.9 (in average 3 levels of Base nitrogen) and application of 100 Kg/ha base nitrogen in Regent*cobra with 176.3 showed maximum amount of pod number per plant. Multiple Mean comparison of interaction effect between base nitrogen levels and cultivars showed that application of 100Kg/ha base nitrogen in Okapi with 69.27 gained maximum seed per each pod.Maximum amounts of 1000 seed weight conducted in application of 100 Kg/ha base nitrogen in Regent*Cobra and non application of nitrogen with 3.91 g.

In order to evaluate the effect of nitrogen and phosphorous usage on sweet corn an experimental split plot form accomplished in randomized complete block design with four replications in Isfarvarin city, Qazvin province in 2005.Nitrogen factor in three levels was put in mainplot inclouding:0, 200, 400 kg/h from urea fertilizer source (0, 92, 184 kg/h pure N)Phosphorouse factor in four levels was put in subplot inclouding:0, 100,200, 300 kg/h from super phosphate triple fertilizer source (46, 92, 138 kg/h P2O5).The results showed N factor had significant effect on number of grain in ear, grain number per row, plant height, nut number, ear length, ear diameter, ear weight, ear wood weight, economic yield and 1000 grain weight. Phosphorous factor also had significant effect on plant height, ear diameter, ear weight, economic yield and 1000 grain weight sweet corn.Among the N levels, the use of 200 kg/h with grain yield 6959 kg/h (with%14wet) had significant advantage.(in comparison with using 400kg/h and without N use with grain yield average of 6365kg/h and 5694kg/h).Among the P levels, the use of 200kg/h P with 6773kg/h was in superior group and the interaction of using 200kg/h had the most yield among the interactions.The interaction of using N and P in harvesting stage had significant effect on growth indexes (LAI, CGR, TDW), ear weight, 1000grain weight and grain yield. N2P2 (N=200kg/h, P=200kg/h) was the best factor of interaction. Regarding the results of N=200kg/h and P=200kg/h increasing the crop growth rate, leaf area index and photosynthesis had leaded to increase the yield.

Pleurotus ostreatus called oyster mushroom belongs to edible mushrooms. This research had been studied the effects of electromagnetic field (B=0.25, 1.2, 3.3 mT (DC) ) for 8 and 4 hours on Pleurotus ostreatus in 50 days period. Sexual reproduction stimulation studied by the pins which produce macroscopic observation. Nutritional value had been tested via measuring soluble proteins by Lowry method and profile of proteins studied by SDS-PAGE. The obtained results by using SPSS and Excel softwares and Duncan test showed the increase of protein amount comparing to control sample in all mediums except the B=1.2mT(DC), t=4h treatment. These tests showed sexual reproduction stimulation by B=3.3mT (DC), t=8h magnetic treatment comparing to control sample. Gel electrophoresis study showed omiting some of the protein bands in some mediums and increase, increasing the new bands in many treatments.

Soil cyanobacteria seems potent organisms considering pharmaceutical characteristics. Antifungal, antiviral and antibacterial abilities have been shown and recently two special substances with anticancer and HSVII abilities have been discovered in these organisms. Nostoc sp; may be considered from salt adjustment and viability at high temperatures point of view. Soil collection had been done during one year. Soil samples had been cultured and after isolation and identification of cyanobacteria, this strain had been selected and cultured in BG-11 medium under 2 micromol quanta.m-2.s-1 white continuous illumination and 450C temperature. Salt treatment was 1% NaCl and had been done under limited carbon dioxide condition. Growth was evaluated using optical density (OD750). Pigments were extracted and assayed as methanolic extract. Ammonium liberation was assayed on different days at 1% salt concentration conditions. Salinity and temperature stresses had been analyzed by pigment content flactuations. Results showed that this strain may be viable at 45oC. The highest rate of ammonium liberation was related to 1% salinity at second day. The highest rate of pigment content was related to carotenoide at invivo and chlorophyll (a) and carotenoide at invitro condition. The highest amount of chlorophyll had been shown in third day and carotenoides at the first day after inoculation. As a conclusion, these strain seemed viable in saline soils and temperate humid conditions.

This research was carried out to determine the more salinity tolerant species of Agropyron desertorom, Bromus tomentellus, Secale montanum. Two genotyps were selected for each species. The experiment was conducted based on a factorial design including five salinity levels of 0,100, 200, 300 and 400 mM Nacl and Cacl2 treatments. The research was performed for germination characterisrics in laboratory conditions. Data were recorded and analyzed for seed percentage and speed of germination, length of root and shoot, length of plantlet, ratio of S/R, vigour index and plantlet dry weight were evaluated.According to the results in the higher stress values showed that speed of germination in all of the species had significant decrease (P<0.01). Also, Secale had the highest percentage rate and speed of germination between grasses. In the other hand, vigour and plantlet dry weight characteristics under salinity different levels showed significant differents (P<0.01). Agropyron had the higher vigour index than the other species, but in the study of plantlet dry weight characteristic, Agropyron had the minimum weights.