Vegetation cover of arid and desert areas is mainly formed from halophyte plant species. These species are important in terms of feed resources for domestic animals such as sheep, goat and camel in desert areas and also for soil conservation. Because of there is not available information about nutritive value of these annual species, an experiment was conducted to determine the nutritive value of five annual halophyte species including Gamantus gamacarpus, Petrosimonia gluaca, Salsola crassa. Halotis occulta and Halocaris sulphaiea. Chemical composition: digestibility (by in-vivo method, pepsin- serolas), preference value (by cafeteria fashion) and voluntary intake were measured by using some Baluchi male sheep. Dry matter digestibility, digestibility of organic matter and digestibility of organic matter in dry matter were statistically different among treatments (p<0.05) and H.su, H. oc and p. gl showed higher digestibility relative to the other species. The amount of crude protein, fat and crude fiber of species was between 6 to 11.6, 4.2 to 6.8 and 8.5 to 20.4 percent, respectively. The voluntary intake of animals were different, so that the highest daily consulJ1ptiqr) of animal was 362 gram from H.su and the lowest was 215 gram from H.oc. The preference value of H.oc with 18.09 percent was significantly (p<0.05) lower than the other species.

This study was conducted in order to survey factors affecting distribution of vegetation types and the relationship between vegetation and soil characteristics in Sirjan playa, Southwestern Kerman province. The study area was one of the most ancient catchments in central Iranian plateau including formations from Precambrian to Holocene, an area of about 274194 ha. After identifying playa area by aerial photographs and topography maps, vegetation was studied using plotting method along transect. In addition, for pedological study, profiles were dug in each vegetation type. Soil characteristics such as texture, acidity, electrical conductivity, organic matter, lime, gypsum, sodium, potassium, calcium, sulfate and bicarbonate were measured. Results showed that from center of playa toward heights, in all aspects of playa, water table depth increased and electrical conductivity decreased. The amount of anions and cations of soil varied, and ratio of anion/cation was obtained. In addition, soil texture became lighter and stability of soil structure improved. This variation caused different vegetation types from margins of playa to heights of 1650-1710m. Vegetation types established from center to outer of playa were as follows: Halocnemum, strobilaceum-Halostachys, belangriana, Tamarix passerinoides, Seidlitzia rosmarinus-Salsola sp., Seidlitzia rosmarinusArtemisia sieberi. After humid margins, vegetation types such as Artemisia sieberi-Zygophyllum eurypterum and Artemisia sp.-Astragalus sp. were established respectively. Therefore, in this region, two factors such as salinity and water ground table were the most important factors affecting on establishment of vegetation types.

Salsola sp. known as shoor or shooreh in most parts of the country, are annual or perennial plants from Chenopodiaceae family. In desert regions, especially in northern margins of Iranian central desert Salsola sp. is available and extended from 1000 m above sea level altitudes. These plants are resistant to drought conditions and tolerate relative salinity of soils. In Semnan province, 13 species of this genus were collected and determined among which six were annual and seven perennial. The most important genera of Sal sola in this region based on their role in supplying forage and in green cover composition of ranges, were S. arbuscoliformis, S. rigida cf Orientalis and S. arbuscula. Although some annual species like S. kali have shown special abilities in forage production under harsh conditions in many parts of the world, this study was carried out to determine Salsola characteristics in Iran. In ranges of arid regions, especially in winter grazing ranges of Semnan province, Salsola sp. is an important component of green cover. Animal husbanderers, especially nomads believe that Sa/sola plays a role by providing salt for domestic animals in addition to its essential role as a forage in grazing cycle from ranges. Usually in ranges with Salsola, a part of grazing time that ordinarily is at the end of the day will be devoted to these ranges. Domestic animals would graze and take needed salts from these plants so that there is no need for putting salt stones in the area. This part of grazing is effective in health of livestock nutrition and helps the shepherd to lead the herds toward watering places. Protein and dry matter production of some Salsola sp. is considerable and can be compared with Medicago sativa.

Field experiment was conducted in 2002 at Shirvan area to evaluate multispecies competition of weeds with winter wheat (Triticum aestivum) and its effects on wheat yield and its components. Sampling was done by a quadrate (50cm × 50cm), randomly. To determine effective weeds on wheat yield, l/W and l/LnW regression models showed better fit to data. Results showed that despite presence of Avena ludoviciana, Erysimum cheiranthoides, Polygonum avicular, Rapistrum rugosum, Chenopodium album, Salsola kali, and Sonchus sp. in the field, only Avena ludoviciana, Salsola kali, and Rapistrum rugosum had significant reduction effects on wheat yield and reduced number of fertile tiller and number of seed per m2but had no effect on 1000-seedweight and harvest index.

In this investigation a karyological study ofl Salsola abarghuensis from north of Abarkuh playa is presented. The work deals with number, size and chromosome morphology.The results showed that the chromosome number in this species is 2n=18. From 9 pairs of chromosomes, 5 pairs are metacentric, 3 pairs are submetacentric and 1 pair is subacrocentric, the average of chromosome length is 0.97 micron, the longest 1.17 micron and the shortest 0.64 micron.

Karyotyp of eight species of Salsola was studied using mitotic cell of root tip meristems, studied species were Snitraria, Scrassa, Sdendroides, Stomentosa, Srichteri, Srigida, S.Kali, S.incanescens. Considering the chromosome numbers, they were classified to four groups: 2n=2x=18 (4 species), 2n=4x=36 (2 species), 2n=6x=54 (l species) and 2n=8x=72 (l species). In addition, genome analysis including total lengh of chromosomes, long and short arm length, long to short arm length ratio, were determined. Using levan's method, the karyotypic characteristics of the species were identified.