فصلنامه گیاه و زیست بوم
پیاپی 55 (تابستان 1397)

Vegetation cover is one of the most importantfactors for ecosystem sustainability. Thus, recognizing factors that result in establishment and distribution of vegetation is crucial. This study was carried out to determine the relationship between plant associations and some soil properties in Bahadoran Kalmand protected region. Soil features of plant associations including texture, EC, PH, SAR, Cations, Anions, and OCs were measured and data was analyzed using Principal Component Analysis. The results indicated that, in addition to climatic factors, the plant associations distribution pattern was mainly affected by soil characteristics including EC, PH, texture, and SAR. Generally speaking, depending on habitat conditions,ecological needs, and tolerance, each plant association shows different resistance toward environmental factors and soil properties.

Investigating and introducing flora in each region is important in terms of recognizing biodiversity and managing natural resources. The present study was designed to investigate the biological form, vegetative form, geographic distribution, and medicinal properties of plants in Khalajestan district of Qom. Plants were identified and confirmed using different flora after being collected through field operation and being transferred to herbium. The results showed that there are a total of 57 herbal medicinal plant species in 27 plant families in the region. Asteraceae with 10 species, Lamiaceae with 9 species, and Crucifrae with 5 species are the most common medicinal plant species in the region. The most common biological forms in the region are hemicryptophytes (40%) and trophytes (36%). Additionally, the geographical distribution of the medicinal plants of the region is mainly Irano-Turanian (55%), Irano-Turanian and Mediterranean (17%), and Irano-Turanian European Siberian (11%). These plants are commonly used for curing gastrointestinal diseases and the most useful herbal organ in these plants is their leaves. Therefore, it can be concluded that Khalajestan region of Qom is an important genetic reserve of medicinal plants.

This study aimed at investigatingcopper and zinc concentrationsin soil and Canolaplantorgans in Saveh-Hamedan roadside to calculate bio-concentration factor, translocation factor, and Canola’sphytoremediation capacity. Soil andplant sampleswere collected from the 5-, 10-, 20-, 40-, 80-, and 160-meter distances from the roadside, and the amounts of copper and zinc in soil and inCanolaplantorgans were measured. The results showed that the highesttotaland availableamountsof copper were respectively obtained fromthe 40- and 20-meterdistances from the roadsidewhich shows a 4.54 and 20.67% increase in comparison to 160-meter distance. Furthermore, the highest amount of total and available zinc was obtained from the 40-meter distance from the roadside where the total zinc amount was 10.72% more than its amount in the 160-meter distance. The highest amount of copper in root, shoot, and seed was respectively 20.20, 19.05, 9.05 mgkg-1. Additionally, the highest amount of zinc in root, shoot, and seed was 22.46, 43.79, and 49.82 mgkg-1, respectively. Copper and zinc in Canola grain were at normal level. The factorof zinc translocation from root to shoot and from shoot to seed was more thanoneacrossalldistances. It can be concluded that Canola can be used for cleaning the soil contaminated with zinc.

In traditional medicine, five-finger plant is considered aherbal medicine for curing diseases related to women.One of the main problems in its cultivation and use is the lack of germination and stabilityin crop conditions. An experiment was carried out at the Agricultural Laboratory of Payam Noor University of Shahriar in order to achieve a strategy for breaking seed dormancy in five-finger (Vitex agnus-castus L.). The experiment was conducted in 2017,following a completely randomized design with three replications and 50 treatments. Germination percentage in Vitex pseudo negundo seed was statistically analyzed. The results of the analysis of variance showed that different treatments for breaking seeddormancy had a significant effect on germination percentage of this medicinal plant at p<.01. The highest germinationpercentage in five-finger seed (60%) was observed in 120min sulfuric acid treatment plus a two-week chilling with 500ppm of gibberellic acid. The results of this study showed that Vitex pseudo negundoseed had a combination of physical and physiological type of dormancy and the hard shell can be affected by the sulfuric acid treatment while its physiological dormancy can be reduced using chilling and gibberellic acid.

Cadmium is one of the heavy metals which is not necessary and too poisonous for plants and animals. In this study, the toxic effect of cadmium chloride on Black Nightshade (Solanum nigrum L.)wasinvestigated. Plants were grown in Perlite with Hoagland solution, containing different concentrations of cadmium (from 0 to 1000 mM)). Samples were collected from leaf and root tissues of forty-day plants in order to analyze the morphological and physiological parameters.The results of shoot and root elongationshowed that the majority of cadmium levelsdid not have a significant effect on root length and the observed reduction was not noticeable. Furthermore, the six levels of cadmium (i.e., 0, 62.5, 125, 500, & 1000mM) were not different and had no significant effect on stem length and photosynthetic pigments at p<.05. The results indicated that cadmium is highly absorbable in Nightshade and, with an increase in its concertation,its accumulation increases in plant tissues in a way that a significant difference is observable across different cadmium levels. Since the absorbed cadmium is mostly transferred to the leaves and considering the results of shoot and photosynthetic pigments and lack of significant effect of cadmium on these parameters, it can be concluded that this plant has a high phytoremediation potential.

Germination plays a significant role in the appropriateestablishment of plant and its ultimate performance. Drought can have an effect on the reduction of germination rate and percentage. Applying strategies that increase plant germination and growth is considered an important factor in agriculture. The present experiment was carried out to analyze the effect of silver nanoparticles on germination indices of two valuable medicinal species of Peppermint (Mentha sp). The study was performed following a completely randomized factorial design with two factors (species and silver nanoparticles) and four replications in University of Kashan. For simulating drought tension, Polyethylene Glycol (PEG) was used. Drought treatments were considered at four levels (0, -0.3, -0.6, & -0.9 MPa) and silver nanoparticle treatments were at four concentrations (0, 10, 20, & 30 mg/L). The results showed that drought tension significantly affected germination percentage and root length at p<.01 and other indices at p<.05. In drought conditions under -0.3 MPa, silver nanoparticles resulted in a return of conditions and elimination of the effect of tension on plant root.

Galbanum (Ferula gummosa Boiss.) species is one of the plants with medicinal and industrial values in Northern Khorasan rangelands. In an attempt to develop its habitat in this province, the seeding process of this species was carried out in seven habitats in 2016 and 2017, following pit-seeding method. To investigate the effect of two important physiographic factors including altitude and slope aspect along with seeding time on germination and bud growth length of Galbanum seeds, samples were obtained from the length of buds, early in May under the same climatic and edaphic circumstances, along 100-meter transects across all altitudes, four slope aspects, and four seeding times. The results of the analysis of variance in different treatments for all three factors under study obtained fromDunnett's T3 Test showed that the highest bud length growth occurred in E4 altitude, Northern aspect, during December (p<.01). There was no significant difference between E2 and E3 altitudes and also Southern and Eastern aspects. In addition, the lowest bud length growth occurred in E1 altitude, Southern and Eastern aspects, during February (P<.01).