نشریه خشک بوم
سال ششم شماره 2 (پاییز و زمستان 1395)

In order to selecting of salinity tolerant variety (ies) of Canola in saline conditions and determination of the salinity response, 60 canola varieties were evaluated during two years. In the first year we reduced the number of varieties in the way of logic reduction by Augment experiment. Total of 41genotypes were eliminated and 19 of them were evaluated in the second year. So, the salinity response of selected varieties was investigated in this paper. The experiment was conducted as a split plot design with randomized complete block design in three replications. The salinity of irrigated waters (2 and 11 dS/m) were as main plot and varieties were placed in subplots. Based on the results of the experiment, the average of grain yield was 2419.8 and 1456.5 kg.ha-1 in high and low salinity conditions respectively, so that there was significant differences between them at 1% level of probability. In the low saline condition, the varieties of Hyola401, Opera, Option500, Sarigol, Hyola420, SYN and Option501 were produced higher grain yield rather than others. Also in the high saline condition, the varieties of Hyola420, Hyola401, Option501, RGS, Mozart, SYN, and Rindow had higher grain yield rather than others. Evaluated of the grain yield in both low and high saline condition showed that the varieties of Hyola420, Hyola401, Option501, Opera, RGS, Option500, Mozart, SYN, and Sarigol were produced highest average yields of 2871.4, 2814.4, 2400.7, 2394.7, 2347.4, 2338.5, 2295.4, 2288.5 and 2178.8 kg.ha-1, respectively.

In this study, annual changes in number of dusty days in Iran over the period of 1965–2005 (41 years) wre investigated. Mann-kendall test, spearmans-Rho test and Autocorrelation test were applied to quantify the trend. Mann-kendall and spearman's test showed similarity in the results, in compared with Autocorrelation test. This study reveals that the all studied stations showed a trend, but among them, only 26 trends were significant statistically, at Mann-Kendall test (16 stations had decreased and 10 stations had increased trend). Spearman’s Rho was significant for trends at 27 stations (17 stations with a decrease and 10 stations with an increase in trend). The autocorrelation test results shows, 33 stations had significant positive or negative trends. The most decreasing and lowest slope was in Abadan and Tabriz stations with values -1.92 and -0.1, respectively. The most increasing and lowest slope was in Iran shahr and Gorgan stations with values 1.97 and 0.8 respectively.

Vegetation cover establishment in marl geological formations due to some physical and chemical characteristics in most arid and semi-arid land associated with numerous limitations. For a proper understanding of the status of ecosystems, arid areas need to recognize the dynamic relationship between vegetation and geomorphology. This study included the relationship between land surface properties and morphometric characteristics of streams with distribution of vegetation in marl lands. In this study, according to the Hydrgeomorphic classification, streams morphometric properties and vegetation characteristics to evaluate the impact of morphometric characteristics on vegetation distribution along homogeneous waterways units were measured. Also vegetation cover, surface gravel density and the roughness of microtopography by linear transect was measured. Soil sample were taken and transferred to the laboratory for determination soil characteristics. Streams morphometric characteristics and land surfaces properties relationship with vegetation cover (%) were analyzed by statistical tests.The results showed that there is direct significant relationship between surface gravel density and vegetation cover in marl plain. The results showed that significant role of some channel plan characteristics on the vegetation cover (%) and distribution of different plant types. CCA analysis is not suitable to analyze the relationship between plant species and morphometric characteristics of streams in this area. In conclusion, our results showed that the role of surface gravel density and streams morphometric properties on vegetation cover (%) and distribution of vegetation type in marl geological formations, but the prediction of plant species distribution using CCA analysis, with emphasis on morphometric characteristics of streams in the study area is very difficult.

Sand arrow is one of the most important accumulation land forms in Najjar abad Erg in the Northeastern of toroud village. In this research emphasized on the affiliation between morphometrical and morphological characteristics of species of Alhagi mannifera and Seidlitzia florida sand arrow using regression and multiregression. morphometrical parameters of species including plant height, canopy diameter and morphometrical parameters of sand arrow including length, maximum width of the arrow and volume. Result of correlation analysis indicates different performance between morphometrical and morphological characteristics of Species. In Seidlitzia Florida Species there are high correlation between plant height and length of the sand arrow (0.670) and also canopy diameter and maximum width of the arrow (0.753) respectively, but this correlation in Alhagi mannifera is (0.504) and (0.680) respectively. Result of linear multiregression indicate more correlation between morphological characteristic of Sand arrow and plant height and canopy diameter in Seidlitzia florida Species (0.879, 0.831,0.661) in comparison with Alhagi manniferaSpecies (0.769,0.683,0.523). Results indicate that Seidlitzia florida Species have more prefect mechanism on trapping of sand and formation of Sand arrow. The results of this research will be fruitful in systemic management approach of desert regions, and also can be fruitful for quicksand stabilization projects.

This study was conducted to identify appropriate sites for shrimp farming development in North costal of the province of Boushehr using Geographical Information Systems (GIS). Base layers (thematic maps) were grouped into four main land use requisites for aquaculture, namely, potential for pond construction (slope, land use type, soil depth, elevation), soil quality (soil type, texture, and pH), water availability (distance to sea, and water source), infrastructure and socio-economical status (population density, distance to roads, local markets, and hatcheries). A constraint layer was used to exclude areas from suitability maps that were not allowed to implement shrimp farming. A series of GIS models were developed to identify and prioritize the most suitable areas for shrimp farming. This study shows that the land evaluation model is useful for identifying suitable areas for shrimp farming and for allocating land for an efficient increase in income, effective conservation, and sustainable land management. It was estimated that about 1.7%(1083 ha) of the total land area were highly suitable and, 41.6% (26759 ha) were suitable in the northern costal of Bushehr for shrimp farming. Curve Relative Operating Characteristic (ROC) method was used to asseessof the accurany of model. Amount of ROC method was 0.734. Field results show that since existing shrimp farms cover only (3800 ha) of land, the potential for development of shrimp farms should take into 86% (24042 ha), consideration further political and environmental issues.

In this study¡ to evaluate the effects of drought stress on transgenic tobacco (Nicotinia tabacum L. cv. Wisconsin) containing P5CS gene and non transgenic plants under in vitro culture, these plants were grown on MS media containing 0¡ 5¡ 10¡ 20 and 30% PEG for 28 days. To select the drought tolerant and sensitive plants and also the mechanisms of drought tolerance in transgenic tobacco plants parameters such as wet and dry weight and photosynthetic pigments content (chlorophyll a¡ b¡ total chlorophyll and carotenoid), soluble sugars and total soluble protein content were measured 28 days after PEG treatment. Results indicated that reduction of wet and dry weights and photosynthetic pigments content in transgenic plants were lower than the non transgenic plants. Soluble carbohydrates in both plants in 10 and 20% concentrations, significantly increased. Total soluble protein content were decreased in non transgenic plants in 30% PEG, and remained unchanged in transgenic plants. SDS-PAGE results in leaves showed different protein patterns between transgenic and non transgenic plants and also between treated and non treated plants for example, protein bands about 35 and 45 KD, Proline as a key osmoregulating solute in plants play an overriding role in osmotic pressure adjustment of the cell under water stress condition. Thus transgenic plants containing P5CS gene might be resistant against drought stress.

A large part of the Iran is located in the arid and semi-arid region. Most natural water body and reservoirs in these areas are faced with the problem of evaporation and drought. Underground dams for storage water in the ground, one of the best ways to conserve water in dry areas considered it comes. In this study, we tried using multi-criteria decision-making models to rank suitable sites for construction of underground dams in the Keriyan region in Hormozgan province. For this purpose, at first with field visits, 10 locations were determined suitable for underground dam construction. Then, based on the expert opinions (through questionnaires) and a scientific literature review of 10 criteria, including water quantity, water quality, along the axis of the dam, the dam axis depth, reservoir storage coefficient, volume of reservoir, lithology of the dam axis, slope, water requirement (drinking, agriculture and industry), access (roads, villages and Quarries) prioritization for suitable sites were used. In the following three decision models include TOPSIS, ELECTRE 3 and the Analytical Network process was used. To choose the best ranking and performance models was used nonparametric Spearman correlation coefficient techniques. The results showed that Analytical Network process model with Spearman correlation coefficient 0.91 and 3.33 variance and standard deviation 1.8 was chosen as the best model, And the Bondar underground dam site as well as the best site for the construction of an underground barrier was determined.

In order to investigate effect of humic acid pre-treatment on germination of Purple coneflower (Echinacea purpurea) plant under drought and salinity conditions, two experiments were conducted in labratory of Horticultural sciences at Gorgan University of Agricultural Sciences and Natural Resources (GUASNR) in 2015, in completely randomized design with four levels of humic acid (0, 250, 500 and 1000 mg.l1-) and five levels (0, -1, -2, -3 and -5 bar) drought and salinity stress in three replications. NaCl and PEG were used for salinity and drought stresses, respectively. Results showed that germination and speed percentages, root and shoot length, root wet weight and seed vigor were, significantly decreased by increasing drought and salinity stresses and were zero in drought and salinity level of -4 bar. Impact of humic acid was significant on the mentioned traits until level -3 bar too. The effect of reciprocal humic acid and drought stress were significant in drought stress just in germination percentage and root wet weight, but in salinity stress were significant in total traits. It can be concluded that germination of purple cornflower seeds has more resistant in drought stress conditions than salinity stress conditions. Pretreatment seed of Purple coneflower with humic acid in saline and dry zones can increase germination resistance.