فصلنامه گیاه و زیست بوم
پیاپی 4-5 (زمستان 1384 و بهار 1385)

Plants have ability to resist against cold stress that happens from beginning of coldseason (fall) and during winter. Plants resistance decreases during growth period that causes intensive damages to plants in case of late-cold stress. Plants have different mechanisms such as enzymatic resistance to overcome late-cold stress. In this study the Peroxidase was selected because of its sensitivity to cold. The main goal of this study was isolating of resistant stands of Eucalyptus viminalis to late- cold stress by analyzing of enzymatic responses to late- cold stress. Sampling was done from 8 stands of Eucalyptus viminalis which planted in adaptation plots (3 from Saravan plot and 5 from Anbaran mahale plot in Astara) in the end of Farvardin. Samples treated in -5, -10 and -21 oC. Quantitative and qualitative of Peroxidase activity were done by spectrophotometer and PAGE method, respectively. Increased activity of Peroxidase in resistant stands was detected by appearance of new enzymatic bands in low molecular weight region in compared to control. Results indicated that the S3 stand in Sarvaran was the most resistant one.

One of the most important Factors in cereal yield is quantity of seeder depth which couldaffect on growth and crop yield. In this study, the row corn planter (TAKA) includes fiveplanter units evaluates at three levels of seeder depth (5, 6 & 7 cm) and at three levels ofvelocity (5, 7 & 9 Km/h) from the stand points of yield component. This planter is moreconventional than the others and is used by regional farmers. For evaluation of yieldcomponents like uniform surface and vertical seed distribution, percentage and velocity ofemergence, used to factorial statistical design with tree replicate and averages of treatments evaluate by Duncan test. Analysis of the vertical seed distribution and the percentage of emergence showed nosignificant difference. Analysis of the horizontal seed distribution, from the stand point ofseeder depth showed no significant difference but from velocity factors was significant, so the maximum value of horizontal index was for treatments to velocity of 7 Km/h. Difference of the treatments from the stand points of percentage of emergence, at level of 5٪ was significant. The analysis of Duncan test showed the treatments to velocity of 7 Km/h and depth of 6 cm were the maximum value of percentage of emergence and the treatments to velocity of 9 Km/h and depth of 6 cm were the minimum value of percentage of emergence. Accordingly, the most adequate of working velocity and depth of corn planter is proposed 7 Km/h and 6cm, respectively.

In order to study and compare The yield and yield components of cotton varities in Varamin region this farm experiment was carried out in the framework of a randomized model with four repetitions by the Varamin catton investigation were: Varamin commercial variety, Pak variety as well as Sindoz, Asj2, Siokra and Chirpan varieties. The resulth of this experiment showed that there were some meaningful differences between the weights of 100 grains, the percent of the measure and the weight of cotton pods: Chipran variety with the average of 18/12 grams showed the most weighty of the 100 grains weight, Siokra with the 40/02 percent had the most measure and the Varamin variety with the average of 6, 089 carried the most weight of the single cotton pods. The other results in all treatment indicated that there were no significant differences between cotton like yield, early percent, the number of cotton pods of each crucible and the number of grain in each cotton pod. The regression analysis also indicated that the cotton like yield of all treatments did have meaningful relationship with early percent, but the height of crucible had no significant correlation with cotton pod’s weights. According to the above-mentioned cases, the morphological specifications and better quality the Varamin variety was recommended as the first, followed by Asj2 and 818-312 as the most profitable for cultivation of cotton varities in Varamin region.

The under study area lies between saghghez and Baneh cities of kordistanprovince, from 46 03 45 to 45 5000 eastren longitude and also from 3612 20 to 36 03 00northern latitude. The area of this region is about 16369, 3 hectars that is limited toSiveh-Soor elevations in north, Khan defile and pirbolagh mountain in south, leysmountain in west and Mirdeh village in East. The highest level of this region is knownVazaneh mountain (2715 meters above sea the level) and the lowest level lies aroundsaheb village. The average annual rainfull in this region is estimated between 350 to650 mm and the proportion moisture varies between 14 to 95 percent. In the view ofmorphology, this area is mostly formed of classtic and volcanic rocks that contains theuniform mountainous topography and some low-elevated hills with even erosion levelsThis area has cold and snowy winters and temporate summers. This factor beside theother variables, influences on the vegetation and causes the generation of specific andnative plants that are unique in their category. The plants of this area which grow inspring, are completely natural and they supply a part of food needs of the people inthis area, and are also the source of economic income for the around villages in severalmonths. The other plant diversity of this area is the diversity in range type, that isdistinguishedsix different rang types in the present investigation that is localdistribution, harvesting rate in hectar and ability in forage supply have been the majoraims of this investigation.

The Study of vegetation of a region is very important for best operation of its naturalresources. The Ain-al-Kosh (Ghala) protected region with an area about 2500 hectar is located in 10 Km from south – southwest of Kermanshah. It is situated between longitudes 46° 56 to 47° 3 and altitudes 34°15 to 34° 19. Its maximal altitude is 1733 m. The Collected plants were recognized and determinated families, genre and species ofthem by using of different Flora books and other references. Flora of this region included 105 species from 74 genre belonging to 21 families. Among the families, Asteraceae with %19, 82 Papilionaceae with %18/92 and Poaceae with %15, 32 have the highest contribution. Life forms of the area based on Raunkiaer system are as follows: Therophytes (66 species, 62/86%), Hemicryptophytes (26 species, 24, 76%), Chamaphytes (7 species, 6, 67%), Geophytes (6 species, 5, 71%). Investigation on geographical distribution patterns of plants species showed 43, 4 percent (46 species) of the species belong to Irano Touranian zone. The Other species can be observed in the other zone too. High percentage of Irano Touranian elements can express this fact that this region belongs to Irano Touranian zone.

Tourism is not only a factor of reinforcing cultures, but also a step toward economic andsocial reformation and progress. Tourism restoration can eliminate our country from singleproduct economy in completely competitive modern world, and the cues for this elimination are identifying potentialities of tourist attraction environments and place, and edited plannings for optimum utilization of these environments. Iran is one of the 5 countries with most ecological variation that consequently has naturalvariation, and unique perspectives of its own. One of these precious tourist attracting places is Talesh area. There are a lot of distinguished situations and natural beauties in this area which look interesting to tourists. There are also thick forests with the most beautiful Rush trees which ease the path of tourism and especially ecotourism development due to the increasing number of people who love nature and runaway from urban areas. It was attempted in this study to investigate the role of forest resources to ecotouristic plannings along with introducing tourist and ecotourit attractions of Talesh area. The purposes of this paper are as follows: Surveying the features and identifying the specific environmental values and forest resources of the region.

Selenium is an essential element for animals and human. This element may have anessential role in plant growth, but this has not yet been substantiated. The nutritionalminimum level for animals and human is about 0,1-5 mg kg-1 of selenium in dry fodder/food and intake below that may cause severe deficiency in them. The objectives of this study were to determine the effects of selenium on selenium concentration plants. For this purpose, soil samples were taken from 10 points 0-30 cm depth of surface soil of Lavark experiment station located in Najaf Abad, Isfahan. The study was carried out in a greenhouse using a factorial experiment design in a completely randomized plot with three replications. The treatments were 5 levels of 0, 5, 10, 20 and 40 g Se ha-1, plant including Fescue (Festuca arundinacea). Soil samples were supplied with cow manure at the rate of 0 and 100 kg ha-1. Applied selenium fertilizer rates effects (40>20>10>5>0 g ha-1) were significant on selenium concentrations in all cuts, but they diminished with increasing of cuts. Selenium concentrations were significantly affected by the cow manure treatments (100>0 Mg ha-1) in all the cuts. Cow manure caused diminishing in selenium concentrations of plant and this trend increased with increasing of cuts. The results of this study showed that in absence of organic matter content, selenium fertilizer could effectively increase the selenium concentration and plant uptake of selenium.

Wetting pattern of root zone of plants (diameter and depth of wetted soil) and trend of advanced wetting front under a trickle is a function of soil properties, discharge and duration of applied water. With respect to numerous effective factors on wetting pattern of root zone of plants and trend of advanced wetting front under drip irrigation, and capability of artificial neural networks, it seems that with collection of information for a relative extensive range of effective parameters, shape and trend of advanced wetting front in soil could be predicted. In this research, in 1383 from cropping soil of Zayanderod river banks of Isfahan for combining various variables (such as sandy loam textured soil and applied discharges of 2, 4, 8 and 12 lit/h with 48 lit of irrigation water), first shape and trend of advanced wetting front was measured with a physical model. Then, using Matlab ver 7 software, an artificial neural network named ANN-SL was designed to predict shape and trend of advanced wetting front under a trickle. The results showed that for this sandy loam soil and each of the four applied discharges, the ANNSL has the ability to predict trend of wetting front. In the designed network, RMSE wasestimated as 0٫2602 and the coefficient of determination was R2=0٫991. Small RMSE and large R2 values of network shows proper match between trend of observed and predicted wetting fronts. The sensitivity analysis on parameters entered in ANN-SL showed that with omission of irrigation water amount and time of irrigation, the performance of this neural network is weakened. The omission of physical properties of soil have lesser effect on neural network performance (p<0٫05). With regard to the results, the error of ANN-SL network is equal to 1٪ which is not important in applied cases. Thus, using ANN-SL is recommended for prediction of trend of advanced wetting front under trickle irrigation in similar conditions.