فصلنامه گیاه و زیست بوم
پیاپی 25 (بهار 1390)

The aim of this research was the study of salinity and it’s effect on growth, proline contents and Ions accumulation of root and shoot of Nitraria schoberi plants in 2 seasons (summer as low rain season and spring with high amount of raining content).The soil of research area was collected in 2 seasons and analyzed in ‎different physical and chemical properties. The Nitraria schoberi plants were harvested in 2 seasons too. Dry and fresh weights, succulent index, proline and 3 ions contents (Na+, K+, Cl-) at shoot and root of harvested plants were determined. With decreasing of water content in environment Dry and Fresh weight, shoot succulent index and the proline content as an osmotic protection material were increased at different parts harvested plants. The contents of Na+, Cl- with increasing of salinity at environment increased but the content of K+ in both parts of plants significantly decreased.

The research studied the morphological characteristics of various organs of three Amygdalus L. species in Iran. The different characteristics of the three species were as follows: Shape of the trichomesshape of the basal and cualine leaveslength and shape of the fruits. Presence or absence of trichomes in fruits and flowers. Anatomical features of stems and leaves of the species were observed and analysed by means of light microscope. Distinctive features were: Shape of the stem in transverse sections thickness of cortex presence of tissue preservative around vascular bundle the number of vascular bundle. The anatomical features of the leaves such as shape of leaves in cross sectionthe number of palisade tissue layers، type of guard cells، shape vein‎, and main different was feature observed in tissue structure leaves uniformity which had just spongyof palisade tissue layers mesophyll tissue at vein distinctively differ in the three species.

The genus Lallemantia Fisch. et Mey. belongs to Labiatae family has five species which distributed in Iran and some neighboring countries. In this study nutlet of Lallemantia was examined with SEM and LM. Significant variation mainly useful at the inferageneric levels was found in nutlet shapes, color, length and nature of surface sculpturing. Based on the mentioned features five types of nutlet was identified in this genus which were useful in identification of species, especially in distinguishing Lallemantia baldshuanica from Lallemantia royleana which were morphologically alike.

Improvement the destroyed area of North forest of Iran with forest species like (Quercus castaneifolia, Fraxinus excelsior and Acer velutinum to increase the wood product is very important. Suitable distance planting is important factor to increase the quantity and quality of trees. The statistical method of this project was randomized complete block design,with three block and six treatment (distance planting), (1×1), (1×1.5), (1×1), (1.5×1.5), (1.5×2) and (2×2). This project applied in 1376 at the low zone of north forest of Guilan height, basal diameter and survival of tree were measured after planting height growth and survival was measure every year. From the fifth year to the tenth one, basal diameter was measured. Statistical analysis with SAS model and Duncan experiment showed that there was significant difference in basal diameter and survival in treatments. Distance planting of (2×2) meter was the suitable distance for diameter the‎ survival but for height growth there was no significant between treatments.

In order to study the effect of drought stress on green fodder yield and agronomic traits of fourteen new forage corn hybrids, an experiment was conducted at the experimental field of Seed and Plant Improvement Institute of Karaj, in 2009. The experiment was carried out using split-plot in a randomized complete block design (CRBD) with three replications. The main plots consisted of three levels of irrigation regimes (irrigation after 70, 100 and 130 mm cumulative evaporation from evaporation pan class A) and sub-plots included 14 new corn hybrids. green fodder yield, Ear height the highest ground, leaf green weight, shoot green. weight, green leaf to stem ratio, percent ear to total green fodder were evaluated. The results showed that ‎the difference between hybrids were significant for green leaf to stem ratio, ear height the highest ground, shoot green weight and green leaf to stem ratio and percent ear to total green fodder. No significant differences were observed between hybrids for green fodder yield and leaf green weight. In addition, all of the traits decreased under drought stress conditions. Increasing in drought stress resulted in decreasing of green fodder yield by 27%.

Laboratory trials were carried out to investigate the effect of benzyladenine (BA) on the postharvest quality and vase life of gerbera cut-flowers. Freshly cut flower stems of gerbera cultivar ‘Good Timing’, with four outer disc florets open were put in flower vases containing 0, 10, 25, 50, 100 or 150 mgl -1 of BA for 48 h and then held in flower vases containing 2.5% ethanol and 3% sucrose for 2 methods. The vase was placed in chambers at 25°C and relative humidity about 70%. The treatments were arranged in a Completely Randomized Design with three replicates. Data were recorded for vase life, fresh weight, solution uptake, membrane stability, total soluble solid over time and analyzed statistically. Results revealed that BA with 50 mg L-1 was the most effective treatments on vase life, fresh weight, solution uptake, membrane stability and total soluble solid of gerbera cut flowers.

In recent years stock has had an increasing demand in the flower market due to its beautiful shape, its aroma and its various colours and usage. One of the after harvest problems of this flower in todayُs market is its quality downfall and short life after picking. In order to increase its longevity and resistance, these days different chemical treatments are used. In this study the picked stock flowers were exposed to different chemical treatments such as %4 sucrose +300 mg/l 8- hydroxyl quinoline sulfate and also 150 mg/l benzyladenine + %4 sucrose which are arranged in six different take solution periods (6, 12, 18. 24, 30, 36) hours. This experiment was factorial in the form of completely accidental and it was performed In three repetitions in which the characteristics related to longevity and quality (new weight and increased Length of the florescence), chlorophyll and carotenoid level were measured. The %4 sucrose + 300 mg/l 8-hydroxyl quinoline sulfate the new weight percentage compared to order treatments and became the control treatment. Also 150 mg/l benzyladenine + %4 sucrose increased the length of the florescence and maintained the chlorophyll and carotenoid level.

Common bean (phaseolus vulgaris) has the most under-cultivation areas among cereals in the world and is very important because it contains 22% protein in food diet. Rhizoctonia root rot and crown rot of bean caused by Rhizoctonia solani is one of the most important disease of this crop in Iran. In this study, during 2005-2006, plant and soil samples were gathered from the main under-cultivation areas in Tehran province and totally, 81 isolates of the fungus were isolated, purified and maintained.The morphological characteristics of the isolated including the color of colony, aerial mycelia, sclerotia (regarding form and size), the width of hyphae and the numbers of nuclei per cells were surveyed. 16 improved cultivars of navy bean, kidney bean, French bean, green bean and black –eye bean were used to identify resistant ones. The mentioned cultivars were tested for resistance to the 5 highest pathogenic isolates Rs7, Rs18. Rs21, Rs62 and Rs74 in greenhouse using complete randomized blocks design with 4 replication (15 seeds / pot). Results showed that not only none of the cultivars were completely resistant, but also all of them were susceptible and semi-susceptible and just two cultivars Goli and Sayad kidney bean with the average disease severity 2.58 and 2.9 (using the scale 1-5) were semi-resistant to the disease.

In this research the effects of nano-silver particles on salinity tolerance behaviors of germination stages of Cuminum cyminum L., one invitro experiments were conducted factorially based on CRD with four replicates during autumn 2008. The nano-silver particles treatments and salinity concentration levels consisted of: 0, 20, 40, 60, 80 and 100 mg.kg-1 and 0, 30, 60, 90,120,150,180 mmol.l-1 respectively. For germination test, after treating by solutions, the disinfected seeds were placed on wattman paper in Petri-dish, and located inside the germinator with 20°C. The numbers of germinated seeds were recorded twice a daily, in a 14 days period. Then the germination percentage, germination speed and vigor, were determined. Results showed that the 20 mg.kg-1 of nano-silver particles had the best effect on vigor, germination percentage and speed, fresh weight and the length of rootlet in germinator condition. There were significant differences in salinity treatments. In addition, the treated seeds with 20 mg.kg-1of nano-silver particles showed the highest concentrations of germination percentage, germination speed, vigor of stem in greenhouse condition.