JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2007 | Volume:16 | Issue:62/1 (BIOLOGY ISSUE)|Papers Count:11

The effect of drought stress and exogenous abscisic acid on the ontogeny of vegetative and reproductive organs of Brassica napus L. was studied. Treatments were: irrigated plants without exogenous abscisic acid, droughted without exogenous abscisic acid and with 3 different concentrations (5, 10 and 15 mgr-1) of abscisic acid. The experiment was designed in a randomized complete blocks with 3 replications. Samples of shoots, leaves, buds, flowers and siliques were fixed according to the common cyto-histological methods and studied. Frequency of stomata was determined in 1mm2 of leaf area. Shoots and leaves of plants under drought stress plus higher concentrations of abscisic acid showed higher level of lignifications, reduction in cortex diameter and dehydratation of some of the parenchyma cells. The frequency of stomata tended to reduce. In this study, premature ovules and embryos observed in plants under drought stress and exogenous abscisic acid.

In this study, the species, Dryopteris caucasica (A. Braun) Frazer-Jenkins & Jenny is recorded from the Iranian phytogeographic region. This species can be distinguished from the other species in the immediate environment based on morphological, anatomical and sporological characterization. It occurs in southwestern Asia, the Black Sea coasts in Turkey, and mountains of the Caucasus. Its distribution in Iran can be seen in Talesh and Asalem forests. This species is one of the parents of D.filix-mas.

The present study was carried out to investigate the hypoglycemic effect of the alcoholic extract of Phaseolus vulgaris pods in normal and streptozotocin-induced diabetic rats. After collection and taxonomic identification of plant, the alcoholic extract prepared by suxhlet apparatus. The animals were made diabetic using by streptozotocin (70 mg/kg, i.p.). The normal and diabetic rats administrated intraperitoneally with the extract (0.1, 0.2, 0.4, 0.6 g/kg) or glibenclamide (600 mg/kg). Blood samples were obtained from retro-orbital sinus before administration and 1.5, 3 and 5 hours after administrations. The diabetic rats were administered saline as control groups. The levels of glucose, insulin in normal and diabetic rats were evaluated. The results showed that administration of the alcoholic extract decreased blood glucose and increased plasma insulin in diabetic but not in healthy rats. A comparison was made between the action of the alcoholic extract and a known antidiabetic drug, glibenclamide (600 mg/kg body wt.). It is concluded that this plant must be considered as excellent candidate for future studies on diabetic mellitus. In addition, further comprehensive pharmacological investigations, including experimental chronic studies, should be carried out.

The investigation of the trend in mitosis divisions and increase in the size of cells is the key to understanding how microtubers are formed out of auxiliary buds in the induce conditions. In the induced buds, meristematical cells with high cytoplasmic and nuclear stain ability expand deeper into the inner sections of the buds, whereas in noninduced buds, the area is limited to the apical region. The first signs of microtuberization, observed almost simultaneously in induced buds, are the increase in the size of cortical parenchyma cells in the lower sections and in one side, and mitosis divisions in the inner sections of the meristem. The changes can be observed as of the fourth or fifth day. Most of the growth takes place in the induce medium along the length and the width of the cells. Simultaneous with the diametric growth of the microtubers, the base of the leaves on the microtubers begin their radial growth and due to the cessation of growth in lateral leaves, these locate themselves in the grooves at the base of the leaves. The cortical parenchyma cells begin forming amidon grains during their vacuolar extension at extending the internodes much earlier than pith parenchyma cells. The extension of cells in the subapical region plays an important role in the longitudinal growth of microtubers. In the first stages, the growth of microtubers results from the change in the dimensions of cortical and pith parenchyma cells, due to the reproduction of apical meristem, and later, mainly from the growth of the productive tissue in the pith parenchyma. Longitudinal growth is initially grater than the growth in diameter; however with shift in the position of vacuoles and their arrangement across rather than along the microtubers, the growth pattern begins to change and lateral growth catches on and exceeds longitudinal growth. In mature microtubers, pith parenchyma cells are larger than the cells in cortical parenchyma. The increase in the number of the cells along and across microtubers corresponds to the change in the size of the microtubers and stops when the microtubers become 7 to 8 mms.

Due to various bioenvironmental conditions, numerous plant species grow in Aquiferous Basin Velayat Rud. Among other plants, Fabaceae species are particularly important. Two hundred places were sampled from 2002 to 2003. Herbarium specimens were collected and provided according to scientific methods of plant taxonomy. Result of this research showed that 64 species belonging to 17 genera have been known in geographical Velayat Rud area. The richest genera are: Astragalus (30 species), Trifolium (7 species), Onobrychis (4 species), Melilotus (3 species), and Vicia (3 species). Various sections of genus Astragalus are as Follow: Caprini (5 species), lncani (5 species), Rhacophorus (4 species), and Hymenostegis (3 species). Hemicryptophytes with 40 species, Therophytes with 5 species, Geophytes with 5 species, Chamaephytes with 12 species, and Phanerophytes with 2 species had been determined in Velayat Rud flora. From Hemicryptophytes species, 20 species belonging to Astragalus. Tree and Shrub species (2 species) and Geophytes (5 species) are the least percentage of growth form in the area. From 64 Fabaceae species in Velayat Rud, 17 and 4 species were endemic of Iran and Tehran, respectively.

In the present research which was done during the period of July 1997 to June 1998, histological studies on maturation stages of 40 Longtail tuna and Kawakawa specimen (Thunnus tonggol & Euthunnus affinis) were conducted. It was concluded that the ovaries of these fish had the following characteristics; Germination disk were not present. there were no difference among anterior, posterior and middle parts of maturity stage of ovaries. All observed ovaries were asynchronous. The ovaries had five maturity stages which were as follow: a) Immature          b) Maturing          c) Rippening       d) Ripe   e) Spent Average dimension of oocyte in different stage are as follow:Immature (2.4m) Maturing (>50m) Rippening (100m) and Ripe (200m) for Longtail Tuna Immature (> 12m) Maturing (<40m) Rippening (<70m) and Ripe (> 70m) for Kawakawa.

Salicylic acid (SA) is now considered as a hormone like substances which affects plant growth and development.A field experiment was conducted during 2004 in Shahre-rey, to determine the effects of SA on yield, yield component and anatomical structures of chickpea cultivar Bivanij. The experimental design was a split plot in randomize complete blocks design with 4 replications in which main plot were 2 treatment methods (spraying and watering SA) and subplot were control (OmM) and 3 concentrations of SA ( 0.1, 0.7, 1.5 mM).plant treatment started at the beginning of flowering and continued to 40 days. Anatomical structures, the number of leaves stomata, trichomes, the number of pods, 100 pod weigh, 100 seed weight, and yield per plant have been investigated. Seed proteins were determined by Bradford method. The results showed that spraying SA was better than watering. Yield, 100-seed weight, 100-podweight, total soluble proteins were maximum when 0.7 mM SA was sprayed. The number of stomata increased when 0.1 mM SA sprayed.1.5 mM SA damaged parenchyma tissues in leaves when it watered, as well as sclerenchyma tissue in stems, xylem in root and the number of leaves trichomes were increased.

The response of adult sand flies Lutzomyia longipalpis to sticky traps baited with entained volatiles from a hamster were assessed in the laboratory. In a two-choice test, significantly more females and males were caught on odour-baited sticky traps than on control traps, and only a few adult remained alive and untrapped at the end of experiments. In contrast, significantly fewer flies of both sexes were caught in a series of tests where both traps were unbaited. Twice as many males as females were caught in the control traps in the tests with odours, an observation in accordance with known male lekking behavior around hosts. The results show that sand flies of both sexes are attracted to traps by host odour alone, in the absence of any other host cues or pheromones from the male flies.

This study aims at the evaluation of physiological and biochemical aspects of resistance against soil salinity stress and periodic variations of cotton peroxidase activity, during different stages of vegetative growth, under diverse salinity of natural soil and plant genotypes has been measured.There for two cotton (Gossypium hirsutum L.) cultivars, Siokra and Sahel have been planted in four level of soil salinity [EC=0.6 (control) EC=6.3, EC=12.3 and EC=16 dsm-1]. Field tests in three stages of vegetative growth consist of two foliair, four foliair and six foliair seedlings were performed.In leaves of both cultivars, from 1st to 3rd stages, with increasing salinity stress, increased Na+, cl- concentrations noticeably.Salinity stress decreased RWC, CGR, LAI in both cultivars. Peroxidase activity, of sahel cultivar in all the three stages of the vegetative growth increased and in the resistant cultivar of siokra it decreased in the first and second stages of field, but it increased in the 3rd stage. Regarding the higher resistance of siokra cultivar, it reaveals that this cultivar in the early stage either did not need antioxidant enzyme or used other enzymes for antioxidant activities. Depending on degree of soil salinity, plant genotype (cultivar) and the stage of vegetative growth (in siokra cultivar), the effect of salinity on the activity of antioxidant enzymes was varied. There was a positive correlation between peroxidase activity and the increase in salinity stress in the sensitive cultivar. The peroxidase activity of sahel cultivar was dependent on its early potential level, but in siokra cultivar it was quite inductive. If peroxidase activity is used as a mechanism, in different plants the vegetative stage of its increase is different, because in the siokra cultivar peroxidase activity began to increase in the third stage (5th and 6th foliairs).

The study intends to investigate the effects of methanolic extract of root, stem and leaf of Datura stramonium L. in vegetative and generative phases on the growth process of four bacterial strains, (Escherichia coli, Pseudomonas aeruginosa, Staphylococus epidermidis, Bacillus subtilis) and four fungi strains (Fusarium semithectum, Fusarium colmorum, Ceratocystis ulmi, Rhizoctoina solani). In this research, methanol extract of flower, seed and leaf explants Callus was also treated. Liquid culture, Pour plate, punch, direct drop and disk paper methods was used. The result showed that: Inhibition effect of methanol extract of organogenesis and green calli due to leaf explants on the growth of B. subtilis (ATCC KXI-Al 15561) and S. epidermidis (ATCC 0-1-B29997) was seen (Inhibition zones 22mm and 23mm, respectively). Inhibition effect of methanol extract of clear callus on the growth of E. coli (ATCC W1485 25645) was seen (Inhibition zone 17mm). Effect of methanol extract of organogenesis calli on the growth of C. ulmi (ATCC 32731) was seen. Inhibition effect of methanol extract of green organogenesis calli on the growth of F. semithectum (ATCC 11599) was seen (Inhibition zones 17mm and 17mm, respectively). Effect of methanol extract of green and calli on the growth of F. colmorum (ATCC 15620) was seen. Inhibition effect ofmethanolic extract of stem and leaf in vegetative phase on the growth of B. subtilis was seen (analysis of punch method). Inhibition effect of methanolic extract of leaf and stem in vegetative phase (Inhibition zones 21mm and 21mm, respectively), stem and root in generative phase (with inhibition zone 20mm) and mature seed (Inhibition zones 17mm) on the growth of B. subtilis (Inhibition zone 21mm) was seen (direct drop method). Effect of methanolic extract of mature seed on the growth of P. aeruginosa (ATCC PA103- 29260) (Inhibition zone 21mm) was seen (direct drop method). Inhibitory effect of methanolic extract of root in vegetative phase and flower on the growth of R. solani was seen (Inhibition zones 20mm and 16mm, respectively). The results showed that the effective compound was atropine alkaloid.