IRANIAN JOURNAL OF BIOLOGY
Year:2005 | Volume:17 | Issue:4|Papers Count:9

Oxygen derivatives such as reactive oxygen species (ROS) are considered as the main agents involved in male ill-fertility. ROS excessive generation can propagate lipid per-oxidation (LPO) and inactivate the cells specially sperm cells, having a humble mass of polyunsaturated fatty acids in their membranes. In the present study, the comparison of antioxidant potential of manganese (Mn2+) (with that of zinc, nickle and trolox; a water soluble analogue of vit. E) was conducted in ferrous-ascorbate complex and/or nicotine induced LPO. We used: MDA (an end-product of LPO) detecting technique by spectrophotometric method. The activity of glutathione S-transferase (GST) was also measured by assaying the CDNB-GSH conjugates. The hypo-osmotic swelling test was performed, detecting the membrane integrity. The Student's [-test was the statistical analysis. Our data demonstrated that the addition of trace metal ions (particularly manganese) to the sperm samples, caused a decline in MDA levels and a decreased activity for GST. Manganese exerted better antioxidant results than zinc and nickle. The decreased activity of GST and elevated number of swollen sperm cells and improved motility was equal to a lowered MDA level/LPO rate. Manganese may be used as a potent antioxidant additive to sperm samples to be used for assisted reproduction techniques (ART) like IVF and/or ICSI.

In this study the quantitative changes of the diameter of perikaryon and nucleus of the motor neurons in IXth Lamina (according to Rexed classification method) and number of glial cells within the gray matter of the spinal cord were measured in 2 prenatal groups of mid stage fetus (37d) and late stage fetus (52d) and in 3 postnatal groups of newborn stage (Id) ,sexually adult stage (6mo.) and adult age (>ly/o). Each group consisted of 3 male animals. From all five groups, the tissue sections of 5 micrometer of Cl, C4 , C8 , T4 , T7 , T13 , L4, L7 ,82 and CO1 were prepared and stained with hematoxylin & eosin and thionin . The result indicated that the diameter of perikaryon and nucleus of motor neurons and the number of glial cells increased from mid stage fetus to 6 month old but decreased in adult age.

This study was carried out in the forests of Dodangeh either sides of Shirin Roud river, in 80 km from south of Sari, to determine characteristics and structure of forest vegetation which has never been ecologically studied. Vegetation types of the area were determined through recording different vegetation parameters and tree measurements and by calculating Importance Value (IV) and IV ranks. Furthermore, vegetation profile of the forest along a natural transect of south-north was drawn to reveal floristical and structural characteristics of the forest. Vegetation parameters and tree measurements used in the analysis were recorded in 15 plots of 40*40 m in either east and west of the river. Tree measurements including Diameter at Breast Height (DBH), total height, height of tree to the first branch crown height, crown diameter and form of tree, were recorded for the trees of more than 10 cm of trunk diameter by using measure tape, diameter tape and clinometers. Position of the trees in each plot was determined by recording the distance from a tree to a given x and y coordinates. Based on vegetation structure, altitude and other physiographic characteristics of the study area as well as field investigation, we recognized two elevation units of 790 1100 and 1100-1700 meter above sea level. The dominant forest type in both east and west of the first group was Fagus orientalis-Carpinus betulus-Parrotia persica. In the second group, vegetation types of Fagus orientalis-Carpinus betulus-Alnus subcordata-Tilia platyphyllos and Fagus orientalis-Alnus subcordata-Carpinus betulus were dominant in the east and the west of the river, respectively. Considering IV ranks on all species in all plots, the Fagus orientalis-Carpinus betulus-Acer velutinum forest type was dominant in both aspects of elevation range of 790 to 1700 m. Vegetation profiles of both aspects were also drawn and depicted in the paper. The information obtained on this valuable ecosystem could help better management and sustainable development of the forest area.

The objective of this study was to compare plant biodiversity in A. subcordata and mixed F. coriariifolia - A. insigne plantations of 13 years old. These plantations are 8 km from western Someasara and juxtaposed. For data collecting, random- systematic method was used and nested sampling plots were performed to obtain suitable plot size with respect to species-area curve and 17 and 18 plots were taken from A. subcordata and mixed F. coriariifolia - A. insigne plantations, respectively. Plant species of each plot were collected and identified and their cover percentages were estimated by means of Braun-Blanquet scale. For data analyzing, Shannon-Wiener index (H') and McArthur's Nj as well as Pielou's evenness were used. A total number of 32 and 35 herbaceons species were found in A. subcordata and F. coriariifolia -A. insigne plantations, respectively. The number of woody species (tree and shrub) were 8 and the same plantations. Moreover, diversity measures (H' and N1) and evenness were more in mixed plantations than those in A. subcordata one. There was a significant difference between the two plantations considering diversity and evenness measures (P<0.0001). It was not significant in richness (P=0.315).

Improving the fruit tree germplasm is an important task in Iran in order to use them in the fruit tree breeding program, because Iran is one of the arid and semi-arid regions in the world. However, cultivar introduction and study of stress resistance source in the fruit tree is essential in fruit tree breeding program. This research was carried out on nine Asian pear genotypes (Pyrus serotina Rehd.) that was introduced to Iran by Dept. of Horticulture, Tarbiat Modarres University from Belgium in 1998. The asian pear genotypes are named KS6, KS7, KS8, KS9, KS10, KS11, KS12, KS13 and KS14. Also a native Pear cv. Shah Miveh was used. Three irrigation treatments were applied: control, mild stress and severe stress. The control was irrigated to provide non-stress conditions. In mild drought stress, Plants irrigated when soil water potential reached - 0.5 MPa and in severe drought stress, plants irrigated when soil water potential reached - 1 MPa.Proline content during two years (three times a year) and soluble sugar (four times a year) were measured. Proline content was affected by drought stress and genotype. In all cases proline content under drought stress was highest and in control was lowest. Also the differences between proline content in the mild and severe drought treatment was significant. In these treatment proline content in KS6, KS7, KS9 was lower than the other genotypes. Soluble sugar increased significantly in the mild and severe drought stress treatment in early stage of the experiment, but this treatment doesn't show any differences significantly.

Our previous study has shown that, Atraphaxis suaedifolia an endemic species from Tabriz. is facing serious extinction hazard, so that, 2-4-years-old plants are absent from its natural habitats. In order to study some external and internal factors involved in the endangering of this species, the effect of some factors on seed germination and establishment of seedlings were investigated under laboratory conditions. For a comparison, another species of the genus Atraphaxis, Atraphaxis spinosa being not recorded as endangered and having extended distribution in Iran, was also studied. Results showed that stratification is necessary for breaking dormancy only in A. suaedifolia. The inhibitory effect of high salinity and also optimum temperature for seed germination were also higher in A. suaedifolia than A. spinosa. Under the same environmental conditions, the germination percentage and rate in A. suaedifolia was 2-7 times lower than that in A. spinosa and the highest germination percentage in the former was only 20%. A high rate of seedling establishment was achieved in the hydroponic culture media compared with soils from its natural habitat, likely because of supplying plants optimally with nutrients. In the hydroponic culture media, salinity (NaCI) up to 80 mM results in increasing fresh weight and length of plants, and also in the succulence of leaves. It could be concluded that, a low germination percentage, relatively high temperature requirement, high sensitivity to salinity having internal origins and low survival of seedlings of soil-grown plants having external origins, are the important factors involved in the endangering of this species.

Fagus is one of the most abundant and economically important genera of woody plants in the North of Iran. Izozyme diversity of Fagus orientalis Lipsky was investigated in 14 Iranian beech populations originating from the major part of distribution range of this tree species in Hyrcanian zone (Southern coasts of Caspian Sea). Enzyme variation of beech populations was studied using 6 isozyme Loci at 3 systems including Menadion reductase (MNR), isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH) by starch gel electrophoresis. Among 15 observed alleles, 8 rare alleles (less than 5% of the allelic frequency) and 4 specific area alleles (observed in less than 5 populations) were detected Results indicated that all rare alleles are not specific area ones. Population Neka at elevation 900 m above from sea level, Kheirud at elevation 600 m and population Asalem at elevation 600 m showed the highest number of area specific alleles. Observation of some geographical trends in alleles MNR-A/B and MDH-A/C were due to important ecological differences among the studied populations (from East far to West far and from lowest to highest borders of beech forests in Iran).