PLANT AND ECOSYSTEM
Year:2011 | Volume:6 | Issue:24|Papers Count:9

The epiphytic lichens Flavoparmelia caperata was collected randomly from mountain forest sites Firozja (north of Iran) ,780m altitude and 36o 05' N latitude and 52o 40' E longitude, and Physcia dubia was collected randomly from forest sites Daronkola (north of Iran) ,220m altitude and 36o 21' N latitude and 52o 43'E longitude. The study aimed to indicate the effects of seasonal changes as stress and to compare their antioxidant enzymes activities. The results showed that in winter the activity of catalase, ascorbate peroxidase and peroxidase was significantly more than spring in both species. In spring polyphenol oxidase activity was significantly more than winter in both species. The results showed that seasonal acclimation depended on the changes in antioxidants enzymes activity in lichens.

Mycorrhizal symbiosis and acid phosphatase production in tress are two important characters to determine the mineralization of organic phosphates into inorganic form. Soil samples from rhizosphere and hairy roots were collected from two Makesh and Fandoglo habitats in spring and summer. Mycorrhizal symbiosis, colonization percentage of hazel‎nut and acid phosphatase activity were measured in soil samples.the results indicated that acid phosphatase activity was higher in Makesh habitat than Fandoglo habitat in both seasons.The results showed that hazelnut had mychorrhizal symbiosis with 48 and 17 colonization percentage in spring in Makesh and Fandoglo habitats, respectively. Colonization percentage in summer was 55 and 22 in Makesh and Fandoglo habitats, respectively. The available phosphate in Fandoylo was 2.5 times more than its amount in Makesh habitat. These differences can be related to the more density of tress and higher mycorrhizal colonization in Fandoglo habitat.

Cuminum is one of the most important plants of Iran. In this‎ study,‎‎‎ measuring some components of yield containing some morphological traits such as plant height, plant diameter, etc ‎..., the relationship between these components and grain yield as dependent trait can be clarified. This study conducted with three ecotypes of cuminum named “Khorasani”, “Esfehani” and “Kermani”. The experimental design was a randomized complete block design (RCBD) with three replicates. The results showed a significant relation between 1000 seed weight, plant height and plant diameter as independent variables with grain yield as dependent trait. But, there was no significant relation between number of flower per plant with grain yield. Meanwhile, analysis of variance in the present study showed a significant difference between these ecotypes based on measured traits. Finally in multiple regression using the effect of each trait in grain yield, the model showed a relationship between seed weight, plant height and plant diameter as independent variables by grain yield as dependent variable. But, there was no relation between the number of flowers per plant by yield.

In order to maintain and keep the quality and market acceptance of a fruit ,it is necessary to preserve it in a cold storage. Granny smith apples are a variety of foreign apples which maintain their characteristics in storage. Ethylene is simple gas hydro-carbon with the formula C2H4 which considered as an essential herbal hormone in after harvest matters. In Some physiological forms such as fruit ripening, flower senescence and tensions like Flooding, frost and dryness , Ethylene produced more. The active material for producing Ethylene is the sulfuric amino- acid of methionin. In order to assess the effects of low temperatures on the storage life increase of Granny smith apples, a completely randomized design (CRD) research was performed considering the variables of temperature and time of storage in two different treatments. The quantitative and qualitative characteristics in this research were Ethylene production, firmness, titratable acidity (TA), total solid soluble (TSS), vitamin C and the PH in two different temperature levels of +3.5 and -0.5oC at the beginning, at the end and during 4 month storage period were measured. Measuring the Ethylene level was done by GC. The results indicated that with increase the rate of ethylene production,the soluble solids content increased continuosly during storage and titratable acidity decreased during storage.

In order to investigate the effect of drought stress and delay sowing date on seed quality of advanced Rapeseed cultivars (Brassica napus L.), a field experiment was conducted as factorial split-plot arranged in a randomized complete block design in three replications in 2004/06 in Karaj Seed Improvement Institute in this study consideerd ‎two factors: Irrigation at two levels:80% of evaporation as control (I1), drought stress started from stem elongation stage(I2), and planting date: normal planting date as fall (D1) and delay planting date as winter(D2), as main plots, cultivars were: RGS003(V1), Sarigol (V2), Hyola401 (V3), Hyola420 (V4), Hyola330 (V5), RGS006 (V6), RG4403 (V7), RG405/03 (V8), RGAS0324 (V9), RG405/02 (V10), as sub factors. The results showed that there were significant difference on Vigor, cold test, E.C and ph test (1% level). maximum vigor and tolerance to cold test, E.C and pH belonged to normal irrigation, fall sowing and D1I1 interaction. Also in D1I2 and D2I1 had significant different at three primary characters. Study of Simple cultivars effect show that RGS003, Sarigol, RGS006 and Hyola420 c.v. were the best at vigor, cold, E.C and pH tests respectively. Also at the interaction effects of treatments Hyola401 and Sarigol c.v. in the normal irrigation and fall planting date, have a maximum germination at the vigor and cold test respectively. But result shows that, at the delay and drought stress conditions E.C test results showd that minimum pass through from the seed coat belonged to D1I1V5. Then these seeds at this condition had minimum decline that can recommend them for long time store.

In order to study the effect of different zinc levels sprinkle on seed oil percentage, seed yield and oil yield of Rapeseed (L. napus brassica), a field experiment was conducted using a factorial in randomized complete blocks design with three replications. In this study, two cultivars (Hayola 401: C1 and Hayola 301: C2) and four zinc sulfate rates (Z1: 0, Z2: 2/1000, Z3: 4/1000 and Z4: 6/1000) were considered.The Result showed that the amount of zinc sprinkle levels had significant effect on seed oil percentage, seed yield and oil yield (P£0.01). Also the highest level of seed oil yield that was produced in this study was in Z4C1 with 1516 (Kg/h).

To evaluate the effects of application of Zeolite and different levels of drought stress and vigority of canola seeds, experiment was performed at the research field of Pardise of Aboureihan of Tehran University 2008. Two seeds cultivars autumn canola that were produced in the different conditions of irrigation and different levels of the application Zeolite, was stored in storage for one month and then were used in this experiment. The experiment was based on factorial split plot on a Randomized complete Block Design with three replications, Including without Zeolite application, Zeolite application of 10 ton/ha (Zeolite application of low-level) and Zeolite application of 20 ton/ha (Application of high-level Zeolite) and three levels of the drought stress including, irrigation after 80 millimeter evaporation from class A pan (normal irrigation), irrigation after 120 millimeter evaporation from class A pan (medium drought stress) and irrigation after 160 millimeter evaporation from class A pan (severe drought stress) in factorial based on two varieties of Zarfam and Licord of canola. The results showed that Zeolite application of drought stress Lead to reduced daily green speed and increasing the percentage of the green field, mean daily green and Seedling establishment percentage. Such results also showed that Zeolite application of different irrigation conditions, including normal irrigation and drought stress had no significant effect on the seed oil content. During the study between these two cultivars, Zarfam conditions had higher resistance to drought stress than the other.

To consider and determine the best herbiside treatment to control the weeds in potato fields, an experiment accomplished in Damavand byrandom complete block desingn. Dosages of the treatment were Metribozin 750 gr/ha, Pendimetalin 3 lit/ha and 5 lit/ha, Rihmselphoron 60 and 40 lit/ha with 2.5% sitogit, Paraquat 3 lit/ha and the witnees was without herbiside. Paraquat 3 lit/ha had the most effect on the dried weight of Acroptilon repens (L.) D.C after 15 days. After 30 days the most effect of the herbisides were: Pendimetalin 3 lit/ha on Amaranthus viridis L Metribozin 750 gr/ha on Amaranthus retroflexus L Rihmselphoron 60 and 40 lit/ha with 2.5% sitogit on Chenopodium album L Rihmselphoron 60 and 40 lit/ha with 2.5% sitogit on convulvolus. The most successful treatment of herbisides after 45 days were: Pendimetalin 3 lit/ha on Acroptilon repens (L.) D.C Rihmselphoron 60 and 40 lit/ha with 2.5% sitogit, Paraquat 3 lit/ha on Amaranthus retroflexus L and Amaranthus viridis L, Metribozin 750 gr/ha Chenopodium album L, all of herbisides on convolvulus, Rihmselphoron 60 and 40 lit/ha with 2.5% sitogit, Paraquat 3 lit/ha on Chrozophora tinctoria (L.) Juss. The maximum yield was for Paraquat 3 lit/ha and metribozin 750 gr/ha. The result showed that the best herbiside treatment in Damavand to control the weeds is Metribozin 750 gr/ha.

In order to determine the response of wild rocket (Eruca sativa) to low herbicide dose of 2, 4-D on more and less competitive winter wheat cultivars and yield and yield components of wheat a field experiment was conducted at plant pests and diseases Institute in Karaj ,Iran. The experiment included 2 wheat varieties (Shiraz and Tabassi), 4 herbicide doses (0.0, 0.50, 0.75 and 1.0 lit-1 a.g) and 4 Wild rocket density (0, 25, 50 and 75 plant m-2) in Factorial trials based on randomized block design with 4 replications.Results showed that shiraz in all densities of wild rocket have more yield than Tabassi, and by using competitive varieties of wheat ,the need for application of herbicide decreased. This trial showed that variety of Tabassi as a less competitive variety depended on herbicide to control weed more than on shiraz (more competitive variety).Grain yield of variety of Shiraz in no usage of herbicide were more than Tabassi in high dosage of herbicide, So it was resulted that selection of a good variety of wheat for competition with weeds was more useful than chemical treatments.