Peroxidases (Ec 1.11.1.7) are hemoproteins which are widely used in diagnostic test kits as well as various experimental tests. For this reason, there is a great need to suitable isozymes from differrent plant sources.Turnip (Brassica napus L.) is an annual herb cultivated mainly for its valuable seed oil. It is closely related to horseradish (the only source of commercial peroxidase, HRP), thus it may be an alternative HRP. In this research, plant material (leaves no.5, 6 ,7) were collected and extracted at the rosset stage. Enzyme assay and kinetic studies were performed at 25°C and l=470 nm. The result showed that the maximum activity of the enzyme was at 50°C and pH=6. During 30 min, the enzyme was stable at 25-55°C and pH= 4.5-7.5 with no reduction in its activity, but it was inactive at 60-70°C. The addition of 0.3-0.6 mM various salts including (Na+, K+,Ni2+, Co2+, Ca2+, Ba2+ and Zn2+) revealed that the persence of K+, Na+ and Zn2+ increased the activity of the enzyme while Co2+ and Ni2+ had an inhibition effect. The comparison of different concentrations of NaCN and NaN3 on the enzyme activity showed NaCN is more stronger inhibitor of peroxidase in Brassica napus. In the presence of 0.002 mM NaCN, the enzyme activity reduced to half compared with control.

In order to investigate the agronomic response of canola cultivar Okapi to the application of nitrogen and bio-fertilizers, a split-plot design was conducted based on randomized complete blocks design with four replications. The experimented factors included: Nitrogen fertilizer in three levels (Non application, application of 75 kg N. ha-1 and 150 kg N. ha-1) as main factors and bio-fertilizer in 4 levels (Non inoculation, Azotobacter, Azospirillum and azotobacter +Azospirillum) as sub factors. Investigation the oil seed trait showed that maximum amount was obtained in non application of nitrogen (45.3%) and that lowest one obtained from nitrogen application treatments that were located in the same statistically group. The seed oil yield results revealed that application of nitrogenous fertilizer increased seed oil yield and 75 kg N. ha-1 (922.6 gm-2) and 150 kg N. ha-1 (1029 gm-2) had most seed oil yield. Application of all levels of bio-fertilizers also had superior compare to non application, that could de refers to nitrogen fixation. It seems that we can decrease chemical fertilizers by application of combined bio-fertilizers. Also biological yield were affected by the experimental treatments. So the most biological yield obtained from of 75 kg N. ha-1 and 150 kg N. ha-1 treatments. The combined use of bio-fertilizers had significant superior to other treatments. The results demonstrated that Harvest index was not affected by any of the treatments and treatments located in the same statistically group. This indicates that increase in biological and grain yield follows the same process.

Heavy metals pollution is a big problem for the large parts of the world. Lead is a heavy metal with high toxicity that inhibition of germination and retardation of plant growth are commonly observed due to its toxicity. The very important role of salicylic acid (SA) in response to different stresses, namely, modifications and decreasing the negative effects of stress has been established in different studies. The objective of this research was to evaluate the effect of different concentrations of salicylic acid to enhance the characteristics of Brassica napus L. under lead stress. Factorial experimental design was arranged in a completely randomized block design with three replications. Treatments were combination of 7 levels application of lead (0, 0.25, 0.5, 0.75, 1, 1.5 & 2 mM) and 2 concentrations of salicylic acid (5 & 10 mM). The results revealed that increasing lead concentration reduced root and shoot length, leaf area, and root and shoot dry weight, root and shoot fresh weight, specific leaf area (SLA) and leaf weight ratio (LWR). Application of salicylic acid on the other hand, significantly increased the studied traits, although specific leaf weight (SLW) and leaf water content area (LWCA) were significantly increased with an increase in the concentration of Pb (NO3)2 (P<0.01). Generally salicylic acid applications improved plant growth parameters ofBrassica napus L.

To study the impacts of nitrogen division and time of consumption on the agricultural traits of rapeseed (Okapi variety )an experiment was conducted in the factorial design mold based on complete random blocks with two factors and four replications in the farming year of 90-91 in shibloo- Poldasht. The experiment was carried out in three divisive stages of nitrogen (a1 =50%+50%, a2 = 25%+ 75%, a3+ 75%+25%) and three stages of nitrogen consumption (b1 = stem growth + flowering, b2 + stem growth + clustering, b3 = clustering + flowering) as the first and second stages. Based on the obtained results, the impact of the time of nitrogen consumption were significant on the number of cluster, grain yield, oil and harvest index. It was so that in the treatment of nitrogen consumption as 75 percent in stem growth stage, 25% in flowering stage, the traits of the length of cluster, the number of grains in cluster, the harvest index, grain and oil yield showed the highest amounts, and also the highest grain yield, 3990k.g. per hectare was obtained in this treatment. The least grain treatment, 2790k.g. per hectare was attained in the treatment of nitrogen consumption in 25% stem growth and 75% of flowering stages. Regarding the results of this assessment of the highest amount of nitrogen in stem growth and its least consumption in flowering stage can have significant impact on the economy of nitrogen consumption and reduction of the hazards of erosion.

Grain shattering of rapeseed in very sensitive by harvesting time. It increase dramatically by late harvest and early harvest couses to decreas index and yield performance. The goals of the present study were to identify the effect of harvesting date and time in day and night on rapeseed (cv. Okapi) yield, harvest index, some plant character, grain shattering rate and its percentage. The field experiment was conducted as split block design in complete randomized block with three replications in 2006-2007 at the Research Farms of Islamic Azad University, Arak, Iran. The harvesting date treatments consisted of three dates (10th and 26th of June, and 11th of July) and harvesting was taken four times per day and night (6.00am and 12.00pm, 6.00pm and 11.00pm). The results indicate that the grain harvested on 26th June was the most accurate date for rapeseed harvest time in Arak farm’s condition. Harvesting on 26th of June and at 6.00pm was the best term for beginning of harvesting. In this term the grain yield was the highest level up to 3600 kg/ha and the grain shattering percentage was the lowest one, by 14.0%. Any delay in harvesting from 26th June could result in the decrease of the yield and increase of the total grain loss. Harvesting at 11th of July was the critical date for the grain yield loss for two different reasons, first for increase of the shattering from 3.5% to 6.3% before harvesting and the second for grain shattering during the harvesting process in range from 14.8% to 16.3%.

In this study, we present changes of peroxidase (E. C.1.11.1.7) activities in the root of Brassica napusvar. Okapi during rosette stage until ripening of the fruits. Peroxidase activity was determined seasonally over an eight month period. Results showed that total peroxidase activity in the root was highest in mid June and the lowest activities were observed from time of winter dormancy until the beginning of April at which time morphogenic competence of tissues started to increase. Pattern of isoperoxidase bands on poly acrylamide gels (PAGE) showed that there was six inducible isoforms, named as TPA1, TPB1, TPB2, TPC1, TPC2 and TPC3. The isoform TPC3 was purified and partially characterized. Purification of peroxidase from turnip root was achieved by two ammonium sulphate precipitation steps followed by DEAE-sephadex chromatography.The effects of pH and temperature on enzyme activity were determined with guaiacol as electron donor. Highest activity was obtained at pH 6.0-6.5 and at a temperature of 50oC. The enzyme was active at pH values below 7.0 even after 24 h and remained active after heat treatment at 70oC for 30 min. It was inhibited by sodium cyanide rather than sodium azide. Loss of TPC3 peroxidase activity in the extracts of non-senescent root tissues suggests that it might play a role in the senescing process.

Introduction: In recent years, characteristics of Canola and its suitable amenity with all climates and weather conditions invarious points of country, had result in expanding implantation of this plant as a good source of meal oil. This is considered in the general perspectives. Continental amenity of this plant and time difference of its growth period and in its capacity for using agronomy frequency, are the positive points of this plant in Iran. Expanded implantation of this kind with other kinds of corps has started since 1997-98 with the surface of 2893 Hectares. According to the last reports, the implantation of this plant in Iran in 2005-06, was about 119321. The average performance of Canola in that period was about 2035 kilograms a hectare.Materials and methods: The study on Okapi and SLM046 Canola has began since 2000 in research farm of Farokhshahr in the research centre of Chaharmahal Va Bakhtiari. For the possibility of expanding these results to farms, we have tried to set real farm situation for the experiment. These steps were done in 7 periods in 2000-2001 to 2006-2007 continuously. The implantation to cropping the products, has longed about 10 months.

In order to investigate the effect of accelerated ageing (AA) on physiological and biochemical traits of cultivar canola seeds, this study was laid out as a factorial experiments based on a completely randomized design with two factors cultivars (Modena and Okapi), aging level (0, 24 and 72 hours at temperature of 40˚c and relative humidity of saturated) and four replications in the Ferdowsi University of Mashhad at 2019-20. The results showed that the aged seeds of Okapi and Modena cultivars significant decline in germination characteristics. According to the biochemical results, in the treatments of 72 hours of AA compared to the control, oil, total protein and scavenging free radicals of canola seeds, has decreased by 9.89, 4.14 and 28.61 percent, respectively. Likewise, electrical conductivity increased by 84.64 percent. Interestingly, aging affected the content of non-enzymatic antioxidants. Here for example, it reduced flavonoids by 73.79%, proline by 47.18%, and phenol by 17.13% compared to non-aged seeds in Okapi cultivar. On the one hand, Okapi cultivar had great quality characteristics such as oil percentage, activity of antioxidant systems, but on the other hand, it was very sensitive to storage, because, aging caused extremely decline in Okapi cultivar seed quality. So, it is obvious that conditions of seed storage of this cultivar require more attention. In general, controlling storage conditions to minimize canola seed aging and deterioration is critical.