Year:2004 | Volume:17 | Issue:(64 IN NATURAL RECOURCES)|Papers Count:14

Blakeslea trispora, a filamentous fungus, was cultured both in a 15lit stirred tank and 75lit airlift bioreactor. Different rates of aeration and agitation were investigated in related bioreactors in order to find the more appropriate culture conditions for better production of ß-carotene. The results showed that the ß-carotene production by Blakeslea trispora is highly dependent on the degree of aeration of culture medium. ß-carotene yield was enhanced up to 120mg/L when the aeration and agitation rate was increased in stirred bioreactor, up to 2vvm and 400rpm, respectively. However, under similar aeration condition, the production of the desired product was about 0.7 times more in airlift than the stirred bioreactor.

In order to survey effects some environmental factor on growth G. corticata in fiberglass tanks, was chosen four season of year and studied pH, temperature and salinity density 500 gr/m.2. On this way pH, temperature and salinity measured on daily, biometry was done every week once too, Seasons of Spring and Autumn have maximum growth rate percentage and net productivity by 3/74 ± 0/31 ,38/3 ± 5/4 and 3/17 ± Oil ,27/6 ± 3/57 , respectively. In this survey range of temperature was 23 .c to 32°C for Spring and 23°C to 30oC for Autumn. Optimum growth and increased weight acquired in 28 °C . Salinity not showed different range and recorded in 36-40 ppt for the all season. At the other hand pH not showed different range and calculated in 8/14 ± 0104 to 8/78 ± 0105 for the all seasons, so growth rate weight not related to different range of pH and salinity.

order to reclamation of plantation purposes in arid lands, it is necessary to select suitable plant species. Success in reclamation depends on identifying the necessities of mentioned plants, on the other hand these species with their special characteristics have special effects on their surrounding environment and it should be considered. The main objective of this study was to investigate the effects of Haloxylon aphyllum and Calligonum comosum on sand dunes physico - chemical properties and also establishment in Kashan. At the first stage two main areas of established plants (Mulched and no Mulched) were selected. Then according to status of plant cover 8, 100 square plots were established and in each plot some parameters such as plant diversity and percentage were estimated. At the second stage soil sample were taken from beneath bushes, between bushes and control area from two depths, 0-10 cm and> 10 cm. Soil samples were analyzed in laboratory and necessary comparisons were carefully made using some computer software such as Mstatc, SAS and Minitab. The results showed that there are significant differences between treatments. These species increased content of organic matter and N.P.K amounts in sand dunes. Organic matter improves soil structure in long term providing suitable conditions for microorganisms activities and increase pedolozation process.

E. gunnii is a fast-growing forest species from Myrtaceae family. It is a native of Tasmania, where altitude and temperature is lower than the other parts of Australia. It prefers light textured, well drained, moist and neutral to slightly acidic soils. This tree is much desired for its silvery-bluish color leaves and year round fine aromatic fragrance and high resistance to cold and freezing climate. It is an important species for forest plantation on coastal plains of Caspian Sea of Iran. Traditional asexual propagation methods are not effective due to difficulties in production or proliferation of adventitious roots. Unique traits of elite genotypes can be transmitted through in vitro micro propagation. Various types of explants were examined in different experiments, including shoot tips, axillary buds, lignotuber and epitomic shoots. Several experiments were carried out to determine the best disinfectant chemical, appropriate conditions and materials to prevent phenolic compound exudation, explant characteristics, media type and cytokinin auxin ratio. Epitomic shoot explants in DEU medium at 0.5 mg L-1 of Kinetin with 0.01 mg L-1 of NAA gave better rate of adventitious shoot production with fewer calluses. The highest adventitious root obtained with a mixture of NAA and IBA at 0.5 mg L-1 each. Micro propagation of plantlets were successfully hardened and adapted either in the propagator or in the greenhouse with survival rate of 75.2 %.

Short-term effects of grazing systems and grazing intensities on standing crop and forage intake of Bromus tomentellus were studied in Homand Abesard rangelands research Station in 2001 . The rotation and continious grazing systems and heavy, medium and light grazing intensities were investigated by a split- split plot design. The results showed that the rotation grazing system had more effects on decreasion of standing crop and increasing of forage in taking of Bromus tomentellus in comparison of continious grazing system. There were no significant difference between light and moderate intensities of rotation system ,but they differed with heavy treatment significantly .In continious grazing system ,the difference of grazing intensities were significant

To evaluate the variation and deterioration of accessions of Dactylis glomerata seeds, which have been collected in Natural Resources Gene Bank, research programs were carried out using 31 collected accessions. All of accessions were independently examined in complete randomized design with three replications in two different situations, named as germinator and glasshouse conditions. The test in germinator condition included, Germination Percentage (G.P), speed of germination and vigor and the test in glasshouse, included G.P, speed of germination, plant height, number of tillers and root length in 40 days after planting. Significant difference was found among accessions examined in this experiment. Variation between accessions in measured characters was found to be significant in one or both of environments. The results of correlation coefficient study were shown that, 1000 seed weight could affect G.P and preliminary growth of plants in both environments. It was found that speed of germination, could be very good indicator of seed vigor. This result was endorsed by regression model. Negative correlation was found between reduction of G.P, speed of germination and seed vigor in germinator condition and G.P, speed of germination and plant height in glasshouse. Therefore, seed deterioration not only could cause reduction of G.P, but also is able to decrease the speed of germination and seed vigor. In all of the Dactylis glomerata accessions, reduction of G.P, highly affected by origin of accessions. It was not possible to differentiate between the effect of maintaining condition and origin of seed collection. Therefore, it suggests that, for better managing the Gene Bank, accessions, but not species, have to be considered as regeneration unites of collected seeds.

The extent of area is about 1000 hectars. This is a part of Binalood in north-western of Mashhad .The average maximum temperature is 34.6°c in July and minimum temprature is 34.6°c in January .A floristic study was done for the area plants and then biological forms and plants chorotype were identified .In this research 45 family, 195 genera and 266 species were identified. The largest plant family is Asteraceae with 34 genera and 51 species and largest genera is astragalus of papilionaceae with 6 species. Chief biological forms are: Therophytes ,Hemi cryptophytes and Cryptophytes. The most of plants chorotype with 52.3% is related to Irano -Turanian

The effects of age and growth phase on micropropagation of Prunus avium was investigated. Axillary and apical buds of 4 genotypes of Prunus avium collected in winter from north forests of Iran and cultured on DKW medium supplemented with different concentrations of BA and IBA. All of the trees were in adult phase at approximate ages of 45, 100, 100 and 150 years. Shoot proliferation and elongation, vitrification and rooting were investigated. Genotype of the trees strongly influenced shooting and rooting ability and vitrification of the explants, while age of the plants did not play an important role. The best hormone concentration for shooting was I to 2 mg/L BA. The oldest tree showed the highest multiplication rate. Lower concentrations of BA were more suitable for shoot elongation. Genotype 3 (100-year-old tree) showed the highest rooting percentage. Genotype 4 showed the lowest percentage of vitrification and the lowest number of vitrified shoot was observed on DKW medium .Although there are significant differences between different genotypes but it seems that this propagation method can be used for all different genotypes of adult and juvenile Prunus avium plants.

The objective of this project was to study the effects of salinity and dryness on germination and seedling establishment of two species namely Elymus junceus and Kochia prostrate under glasshouse condition. For this purpose, two separate trials were established using a split plot design. The different levels of salinity and irrigation duration were assigned as main plots and sub plots respectively. The first trail was conducted on a salty soil with four different salinity levels as 0.0,6.78, 13.26, 18.4 milimol/cm and the second one was conducted on a unsalted soil comprising 25% manure, 25% sand and 50% field soil. In the first trial normal water was used for irrigation but for artificial ones the irrigation water was treated with NaCl and CaCl2 the same level of salinity in the first trial. The irritation interval was 10, 15 and 20 days. The effects of salinity on germination were determined in the first 14 days and later on the drought treatments in both trials were studied on seedlings. Three characters namely: germination percent taye, seedling growing and seedling weights were measured. The results showed that salinity and dryness decreased seedling growing and seedling weight in two species. Elymus junceus was more resistance to salinity and dryness effects than the other one. In 13.26, 18.4 milmoh/cm salinity levels no seeds germinated. In conclusion two species germinated in normal soil.

In order to Study of genetic variation among 20 local and foreign accessions of annual ryegrass (Lolium multiform ),an experiment was conducted using a complete block design with Three replications in Alborz Research Center, Karaj, Iran. during 2000 and 2001. Forage dry matter yield, basal cover, ear emergence date, pollination date, stem number per plant, stem height and persistency were assessed for 5 and 2 cuts during 2000 and 2001, respectively. The data were collected and analyzed for total annual dry matter yield and average values of each morphological trait. The data were also analyzed as split plot in time over two years. Phenotypic correlations among characteristics were determined for all pair-wise combinations. Using principal component analysis and cluster analysis the accessions were classified based on 7 characters. The results showed significant differences among accessions for all of characters for individual year and combined over two years. There was a positive and significant correlation between dry matter yield with both plant height and persistency. Basal cover was negatively correlated with persistency and positively correlated with stem number. Using principal component analysis, the first three components determined 83% of the total variation. Annual dry matter yield, plant height and persistency was the most important traits in the first component. Ear emergence date and pollination date were the important traits in the second components. The 20 accessions were grouped into 4 clusters based on multivariate analysis of 7 classification variables. Accessions in cluster I averaged well above the overall mean for forage production, plant height and persistency. The accessions in cluster 2 had higher stem number and basal cover and, that increased their productivities. The accessions in cluster 3 were the late maturity groups and they ranked second for dry matter yield. Cluster 4 characterized by early maturity, lower dry matter yield, and low persistency.

The sangdeh rocky forest where is located at southern part of Sari city ( center of Mazandaran province) is one of the special ecosystems of the high altitude forests of Caspian region due to its special ecological characteristics and [its unique vegetation type such as Betula pendula Roth. communities. The plant diversity at this ecosystem, creates a unique biological environment and feature on the north slopes of Alborz mountain chains. The vegetation was studied to identify and introduce the flora, determine chronologically the plant elements and define their structure. As a result, 181 species, 129 genera and 52 families were determined. The most important families were Rosaceae, Asteraceae, Poaceae, lamiaceae and caryophyllaceous wich contain 41 percent of the total species Hemi cryptophytes, Phanerophytes and Cryptophytes were the most important structure groups of the local biological spectrum according to Raunkiaer Method, whereas according to Suzuki and Arakane Method caespitose Hemi cryptophytes, Rhizom-Geophytes and broad leaved decidous shrubs were the most important life forms. The chorological study and identifying the chorotypes according to Zohary Method, showed that in that part of the Caspian (Hyrcanian) forests, most of the species belonged to Hyrcanian phytogeographical region whereas the least species belonged to phytogeographical Regions= Irano Turanian and Irano turanian-Hyrcanian. Only 33 species were endemic of Iran which contain 1.9 percent of the total endemic species of the country’s flora.

Considering appropriate adaptability of different wild species of pistacia in different arid and semi-arid environment of the country as well as its high value from the point of view of rezin and other chemical production, oil, and pharmacological consumption of their seeds, founding their habitats in the different areas of Markazi province (as a sub-project of the national project under the title of The study of pistacia distribution and related influencing factors in Iran) seems to be important. In this project first of all, the basic information including topographical, soil, climate, geologyl, and landuse map of Nazar Kardeh mountain in Saveh Town ship with 1/50000 scale were prepared and digitized. In order to study the phonological characteristics of the species. The parameters, such as the number of trees in the samples, trees height, trees width diameters, the time of flowering, the time of leaf appearance, the amount of seeds and its color, ... were recorded in sampling areas. After establishing the DEM of the areas, aspect and slope map were also produced using dfdx and dfdy filter using Ilwis Academic program package. On the basis of this investigation the following results were obtained. The distribution limits are located between 1080 to 1293 above sea level. The density of trees are 30 - 50 individuals per ha. The average height of the trees is 3.27 m, and the maximum height is 5 m. The average height of the tree trunk is about 1. 18m.The average tree crown height is 2.10 m. The mean tree trunk diameter (diameter at breast hight) is 7.3 cm. The average hight of the large and small crown are in order 2.1 m and 3.16m