Journal of Plant Biological Sciences
Year:2018 | Volume:10 | Issue:37 |Papers Count:6

The survey of the ecological and m orphological characteristics of medicinal plants is one of the essential requirements for multipurpose use of rangelands. Accordingly, the ecological and morphological characteristics of Ephedra procera were investigated in the mountain rangelands of Urmia. For this end, regarding to the physical and vegetation characteristics; three habitats representing a wide range of areas of E. procera distribution region were selected. Then, the data inventory was conducted within 30 two square meters plots established on transects along 100-meter with distances of 10 meters apart and the morphological characteristics and amount of forage production were measured. To study the relation between distribution of vegetation and soil characteristics, soil samples were taken with three replications along transects. The results showed that the morphological characteristics of Ephedra and soil physical and chemical properties in study sites; are significantly different among the sites. Analysis of variance linear regression equation between forage production of Ephedra with morphological characteristics indicates a significant relationship between forage production and number of plant shoots. The results of studying the relationships vegetation distribution with environmental factors showed that the influence of environmental variables on vegetation is significant which accordingly the factors such as slope, temperature, aspect, porosity, sand, elevation from sea level, percent of gravel, bulk density and electrical conductivity are of the most important factors affecting the distribution of Ephedra species. The results can be used in planning the protection and restoration practices of Ephedra in natural habitats.

In order to study the effects of nano iron oxide on yield, chlorophyll fluorescence indices and some physiological traits of wheat (Triticum aestivum L. ) under rain fed and supplementary irrigation conditions, a factorial experiment was conducted based on randomized complete block design with three replications in Agricultural Research Station of Ardabil in 2016. Factors experiment were included irrigation levels (no irrigation as rain fed, supplementary irrigation at heading and booting stages), foliar application nano iron oxide in four levels (without nano iron oxide as control, application of 0. 3, 0. 6 and 0. 9 g L-1). Means comparison showed that 0. 9 g L-1 nano iron oxide application and supplementary irrigation at booting stage increased maximum fluorescence (Fm), variable fluorescence (Fv), chlorophyll content, nitrogen percentage, relative water content and grain yield compared to non-application of nano iron oxide under rain fed condition. Rain fed condition increased minimum fluorescence (F0) and electrical conductivity. Foliar application of 0. 9 g L-1 nano iron oxide and supplementary irrigation at booting stage increased grain yield 38. 43% compared to no foliar application under rain fed condition.

Seed priming often promotes germination and seedling growth under environmental stresses yet as main negative aspect, primed seeds are vulnerable to aging process. In this regard, the current study was carried out to examine the influence of priming treatments (with water and ascorbic acid) on germination of smooth vetch (Vicia dasycarpa) seeds under osmotic stress (-0. 9 MPa). In addition, we examined whether or not post priming heat shock treatment may maintain this possible advantage by reducing primed seeds deterioration during artificial aging. Treatments included: hydro priming, hydro priming plus heat shock, priming with ascorbic acid, priming with ascorbic acid plus heat shock, control or non-primed seeds. Primed seeds after partial drying faced heat shock at 40 0C for 3h. Following heat shock treatment seeds were exposed to accelerated aging for 0, 2, 4, 6 and 8 days. Priming particularly with ascorbic acid substantially increased germination under osmotic stress. Heat shock treatment significantly improved germination ability of both aged-primed seeds with water and ascorbic acid. The difference between HS treated and non-HS treated primed seeds were more considerable following longer terms (6, 8 days) of artificial aging. The results showed that the restoring effect of heat shock was accompanied with lower lipid peroxidation (assayed as malondialdehyde content), electrolyte leakage and enhanced antioxidant activities including catalase, peroxidase and ascorbate peroxidase.

Salinity is one of the most significant abiotic stresses that affects plant growth and yield in various ways. On the other hand, silica, the second most abundant element in the Earth's crust, increases plants' tolerance under stress; therefore, given the importance of the Purple Coneflower, we investigated the effect of silicon on some of the morphological and phytochemical traits of this a medicinal plant under salt stress. For this purpose, a pot experiment was conducted as a factorial based on a completely randomized design with four levels of salinity (control, 25, 50 and 75 mM sodium chloride), four levels of silicon (control, 0. 75, 1. 5 and 2. 25 mM), and four replications. The experiment was done in greenhouse of Gorgan University of Agricultural Sciences and Natural Resources in 2016. The stress was imposed in hydroponics (perlite and coir) culture medium with Hoagland nutrition solution. Since flowering begun, growth, morphological, physiological and phytochemical indices including root length, fresh weight of shoots and roots, dry weight of shoots and roots, leaf scorch, leaf relative water content, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll, total flavonoids, total phenol and antioxidant activity of the root were measured. Salt stress increased all measured traits to a moderate amount and then decreased them. All traits except the percentage of leaf scorch improved with silicon concentration. The interaction of these two factors was significant in all traits except fresh and dry weight of shoots and the percentage of leaf scorch. In addition, the negative effects of salinity stress, especially on low to moderate levels decreased significantly in growth, morphophysiological and phytochemical traits of the plant with silicon and thereby the growth improved. So, the best salinity concentration to increase the biochemical factors was 25 mM of sodium chloride and the best concentration of silicon to reduce the negative effects of salinity stress was 2. 25 mM.

In order to evaluation of the allelopathic effects of apricot leaves on corn, bean, rye and pigweed an experiment was done with apricot aqueous leaf extract (75% w/v) and leaf powder (3% w/w) treatments and control (distilled water) during seedling stage. Experiment was carried out as a factorial experiment based on complete randomized design. In both treatments, the lowest and the highest loss percentage of shoot and root dry weight and stem and root length was observed in corn and pigweed respectively. Electrolytes leakage increased significantly in bean plants under extract and powder treatments and in rye only treated with leaf extract compared to control (P≤ 05). Aqueous leaf extract and leaf powder treatment decreased the chlorophyll content in bean and pigweed, while increased in corn and rye. Significant increase (P≤ 05) in concentration of soluble sugars in bean and corn after application of leaf aqueous extract and powder, and in rye and pigweed after application of leaf aqueous extract was observed. In bean and rye plants peroxides activity enzyme significantly increased under leaf extract and powder but in corn only on leaf powder treatment. Results showed that the leaves of apricot have an allelopathic potential and its application as aqueous extract or leaf powder has different inhibitory effects on the biochemical, physiological and developmental functions of plants. Due to the negative and significant effects of apricot leaf treatments (extract or powder) on weeds especially pigweed, it can be considered as a biological herbicide or a model for new herbicide.

Potassium has a main effect on plants salinity tolerance through its effect on cells osmoregulation, and the maintenance of cell turgor. The objective of the present study was to investigate the effect of foliar nutrition of potassium sulfate (0 and 1. 5%) on some morphometric and physiological traits of Bidaneh-Sefid grapevine under salinity stress (0, 25, 50 and 100 mM of NaCl). The factorial experiment in a completely randomized design was carried out in a greenhouse condition. Four weeks after beginning of salt stress, salinity caused decrease in plant height, leaves numbers, leaves area and re-growth. Foliar application of potassium sulfate mitigated the negative impacts of salinity on these morphometric indices. Also, application of 1. 5% potassium sulfate resulted in the stability of photosynthetic pigments compared to non-treated plants under salinity stress. In no potassium sulfate treatment condition, with increasing of salinity up to 100 mM NaCl, the amount of ion leakage increased and reached up to highest level (64. 2%). While 1. 5% potassium sulfate treatment decreased leaf ion leakage significantly (P≤ 0. 01) in compared to untreated plants. Leaf relative water content decreased dramatically especially in 100 mM of NaCl treatment. While potassium sulfate spray increased the leaf relative water content significantly (P≤ 0. 01) so that at all salinity levels, the highest amount of relative water content was related to 1. 5% potassium sulfate level. Unlike insoluble sugar, the content of soluble sugar and proline as two osmoregulants has shown an increasing trend in the response to salinity and the application of potassium sulfate and reached to highest level in 100 mM of NaCl and 1. 5% potassium sulfate treatments. Also, with increasing of potassium concentration in foliar application of potassium sulfate and in turn cell Na+ /K+ adjusting, increase in the leaf N, K, Mg and Ca content in compared to non-treated plants was observed. Totally, it seems, potassium sulfate treatment with affecting the water relationships, nutrients absorption and osmotic regulation resulted in improved vines tolerance under salinity stress condition.