Journal title

Investigation of nickel toxicity effect on different aspects of photosynthesis and growth in maize seedlings

fatemeh Ghasemi

To assess nickel-induced toxicity in plants, Zea mays seeds after germination were cultured on hydroponic nutrient solution with nickel concentrations of 0, 50, 100 and 200 micro molar for a period of two weeks. Then its effect on the growth, Hill reaction and photosynthetic pigment's content were investigated. The fresh and dry weight of leaves and roots increased in 50 &muM nickel but decreased in 100 and 200 &muM. The decline in length of root and shoot were observed by increasing Ni concentration.According to results, root and shoot showed differential growth response to varried concentrations of nickel. Ni concentrations up to 100 &muM caused incrtease in the content of chlorophyll a, but it was decreased at 200 &muM Ni. No significant changes in chlorophyll b and carotinoids content observed. The rate of Hill reaction as an ability of chlorophyll a in the reaction center of PSII680 to split water, decreased by increasing Ni concentration.

Inductive Effect of IDE1 on Differentiation of Human Induced Pluripotent Stem Cells (hiPSCs) Into Definitive Endoderm Cells by Using PCL Electrospun Scaffold

Today, induced pluripotent cells (iPS) have been recognized as a new and good cell source for cell therapy. In this study, we examined whether human iPS cells, cultured on scaffolds, can differentiate into definitive endodermal cells, as precursor for hepatocytes, pancreatic and lung cells. Embryoid bodies (EBs) composed of iPS cells then EBs were seeded on electrospinning nanofiber scaffold (PCL). The cells were differentiated into definitive endoderm by using IDE1(induced definitive endoderm). Expression of definitive endoderm markers including Sox17, FoxA2 and Gsc were confirmed by Immunocytochemistry attaining and RT-PCR analysis. In the present study, cells morphology and cells viability were evaluated by using a scanning electron microscopy and MTT assay respectively.The results of this study demonstrated the positive effect of 3D cultures, by using suitable factors, on definitive endoderm differentiation.definitive endoderm by using IDE1(induced definitive endoderm). Expression of definitive endoderm markers including Sox17, FoxA2 and Gsc were confirmed by Immunocytochemistry attaining and RT-PCR analysis. In the present study, cells morphology and cells viability were evaluated by using a scanning electron microscopy and MTT assay respectively.The results of this study demonstrated the positive effect of 3D cultures, by using suitable factors, on definitive endoderm differentiation.

Study of germination ecology of mesquite (Prosopis farcta)

Fariba Meighani

Abstract
Mesquite is one of the invasive, problematic and noxious weeds and special warm and dry areas. This plant in recent years due to high resistance to drought stress level in the vast agricultural lands and orchards spread. Management so it is very important. The following studies were conducted in plant protection of weed research Department Research Institute of during the years 2010: 1- Effect of constant temperature on germination that including 5, 10, 15, 18, 20, 25, 30, 35 and 40° C independent dark and independent light conditions 2- Effect of temperature fluctuations on seed germination: 0/10, 10/20 and 20/30° C 3- Effect of planting depth seed on seed germhnation. All experiments were conducted with 4 replications. mesquite seeds showed no dormancy when detachment from mother plant. Seed germination was strongly influenced by temperature. Light did not play a crucial role on seed germination of this weed. Therefore mesquite seeds were not photoblastic and temperature fluctuations did not increase seed germination of mesquite. The above characteristics are very important in making mesquite an invasive weed. Having precise information of these traits enables us to a better management and control of this troublesome weed.
Keyword: Prosopis farcta, seed germination, seed dormancy, constant and fluctuating temperature, planting depth.

Floristic study of forests Kasf (Khorasan Razavi)

Javad Mohammadi

Vegetation of Kasf forest with an area of over 12 ha, located in the east-west direction at a distance of 20 kilometers north of the city of Bardaskan, between 57° and 52' and 30" to 58° and 00' and 00" East longitude and 35° and 22' and 30" to 35° and 30' and 00" North latitude, in a mountainous arid region with a minimum and maximum temperature of -10 and +45° C , respectively and average annual precipitation of 155 mm, at an altitude of about 1600 m above sea level with 15% slope was studied using floristic method 2 years after fire and life forms and geographical distribution of plant species were determined. Sixty nine plant species belonging to 29 families (25 Dicots, 3 monocots and one gymnosperm). The largest families were the mint (Lamiaceae) with 11, Compositeae (Asteraceae) with 9 and carnation family (Caryophyllaceae) with 5 species. The life forms included Therophytes with 36% (25 species), Hemicryptophytes 29% (20 species), Chamaephytes 16% (11 species), Phanerophytes 13% (9 species) and cryptophytes with 6% (4 species). The high percentage of Hemicryptophytes indicated dominance of cold mountainous climate and the presence of Asteraceae species such as harmala (Peganum harmala) showed sever disturbance had taken place in the region and thus, the need for administering greater ecological care and employing more extensive environmental supervision and management was identified.

Performance of dead Fucus serratus biomass in binary Biosorption of Cd (II) and Ni (II) from aqueous solutions

salman ahmady-asbchin

Abstract
Methods of physical and chemical adsorption of heavy metals, has some disadvantages such as high cost and are ineffective at low concentrations. Methods for biological uptake of heavy metals in recent decades were considered. Among the biological adsorbent include: bacteria, fungi and alga, algae have the highest efficiency of metal uptake. This study determined that the main role in the uptake of metals, nickel (II) and cadmium (II) Alginic acid is responsible. Focus serratus brown alga, as adsorbent in this study used a cost-effective biological and biological uptake of cadmium and nickel ions simultaneously in a batch reactor has been studied. Surface structure of algae has been studied. Adsorption kinetics have been studied, the equilibrium time is about 300 minutes, the Langmuir adsorption isotherm using the equation can be interpreted as the maximum adsorption of about 0/85and 0/95mmol/g are, respectively, for cadmium(II) and nickel(II).

Comparison of structural and ultrastructural differences and similarities of hair and feather follicles

A Gharzi

Formation of feather and hair follicles during embryonic stage is nearly similar but whether they possess a similar structure and organization in mature stage as well? The aim of the present research is to study similarities and differences of these two follicles in adult rats and pigeons. To fulfill this task, after removing follicles from the skin, the follicles processed for light and transmission electron microscopy. The results provided here demonstrated that these two follicle types are similar in having the dermal papilla, epidermal matrix and epidermal stem cells. Moreover, the production of hair and feather fibers in them is almost the same. One of differences seen between these follicle is that, unlike the hair follicle in the feather follicle a distinct compartment, called the pulp, is observed at the top of the dermal papilla. At the center of this pulp as well as the dermal papilla a blood vessel exists, a character which never seen in the hair follicle. Another difference observed is related to the thickness of the basement membrane exists at the interface between the papilla and epidermal matrix. This membrane in feather follicle is much thicker than its hair counterpart. In addition, at the basal region of the feather follicle there is a distinct population of stem-like cells which could not be distinguished in the hair follicle. Based on results provided here it seems that the feather in birds and the hair in mammals have been adapted for different biological tasks.

The Effect of acid rain on growth and physiological responses of wheat plant

G Rabani

Acid rain, which is a wet form of gaseous air pollutants, is formed when air pollutants such as SO₂, NO₂, CO₂ in atmosphere combine with water vapor of clouds. With the addition of concentration of these pollutants the amount of acid rain is increases. Acid rain that is the mixture of sulphuric acid, nitric acid and carbonic acid lead to change in the soil like the decrease in pH, nutrient liberation, the increase of releasing in toxic metals and the decline in fertility of soil that these cases results negative effects on plants. In present work wheat plants irrigated and leaf spraied with four treatments of acid rain which contain sulphuric acid and nitric acid with pH= 2.5, 3.5, 4.5, 5.6 for a period of 32 days, whereas, control plants irrigated and leaf spraied by normal water at pH= 7.4 . According to the results control plants in whole of growth and physiological indexes were better than treatments of acid rain at pH= 2.5 and 3.5, also plants of acid rain treatment at pH= 4.5 and 5.6, were lower in other factors except photosynthetic rate, pigment content and carbohydrate content than control plants. Also acid rain at pH= 2.5 and 3.5 causes white spot in both surface of leaf and tip and border atrophy.