علوم مراتع
سال:1395 | دوره:6 | شماره:3 |تعداد مقالات:13

Range ecology, Range management, Ecosystem, Conservation The book written by seventeen experts in the field of rangeland management, this compilation of essays brings to light the latent issues concerning this subject to readers all over the globe. Though technical approaches can address some issues, social processes ultimately prevent the balancing of these matters.

In most southern provinces of Iran, Soil Salinity is a growing problem particularly in the irrigated agricultural areas and has been found to reduce crop yields. In order to investigate the role of pod removal in seed germination, seedling growth and antioxidant enzymes activity in annual medics (Medicago scutella L.) under salinity stress conditions, a factorial experiment was conducted at College of Agriculture, Shiraz University in 2014 based on the completely randomized design with four replications. The factors included: 1) the presence or removal of seed pod, and 2) salinity stress at five levels involving controls 3, 6, 9 and 12 dS m-1. The results showed that salinity stress has caused the changes of germination, seedling growth and antioxidant enzymes activity. By increasing salinity stress levels, a significant reduction was observed in speed and percentage of germination as well as rootlet length, shoot length and seedling weight. However, the increased levels of salinity stress caused the increased antioxidant enzymes activity. Germination and seedling growth in seeds with no pod were more than seeds with pod, but about enzymes' activity, no significant difference was observed among seeds with and without pod, except for ascorbate peroxidase enzyme activity that was significantly more in seeds without pod as compared to the seeds with pod.

Nepeta species are widely used as medicine plants because of their anti-spasmodic, diuretic, anti-septic, anti asthmatic anti spasmodic, and tonic effects. Nepeta species also have anti-bacterial, anti-fungal, anti-viral and anti-inflammatory activities. Germination and seedling growth are two important stages of the plant development and plant survival. Soil texture is one of the environmental factors, which affects the germination mechanism. In order to evaluate the effects of seed source and soil texture on the germination of N. asterotricha as a medicinal plant, an experiment was conducted in a factorial arrangement based on a completely randomized block design with four replications in 2014. The studied factors included different sources of seed collection (Sanij, Dehbala, Dareshir, Tezerjan) and three types of soil texture (Sand, Sandy loam and Silty clay). Results indicated that N. asterotricha germination was affected by the origin of seed source (altitude, direction, and slope). Seeds collected from Sanij and Tezerjan had the highest and lowest germination percent, respectively. Among different soil textures, soils with sand and sandy loam texture had the best performance. Results showed significant effects of seed sources and soil texture interaction affects the seed germination percent and germination rate (p≤0.01). Seed sources had different responses to soil textures indicating that seed collected from different areas may be compatible with specific soil texture. In general, the light soil textures had better effects on seed germination traits of N. asterotricha.

The study of plant under environmental conditions leads to an appreciation of their physical and chemical requirements for growth and reproduction. It contributes to increase the knowledge of where the plants grow. This study was conducted to determine the main autecological characteristics of Salvia hydrangea L. which is an endemic plant distributed in Mazanadarn province, Iran. The habitats of this species (altitude of 1100, 1700 and 2000m) were identified (2014) and then, the climatic and edaphic characteristics of habitats were determined. Surveys of the plant in the habitats were done along the transect (100m) within quadrant (4m2) with a systematically randomized method during major phenological stages of the plant. Phenological stages and some plant characteristics such as density, canopy cover, plant height and root system were studied. Results showed that in lower altitudes, vegetative growth starts in the middle of February and follows the flowering at the end of May whereas in higher altitudes, the plant starts vegetative growth in the early March and reaches fully flowered at the end of June. The mean annual rainfall and temperature of the habitats ranged from 383-540 mm and 21–24oC, respectively. Results showed that the plant density and canopy cover decreased slowly with increasing altitude while reaching the minimum value in the altitude of 2000m. The root depth of plant in the loamy sand soils was deeper than the clay loamy soils. Density and other measured vegetal factors of plant decreased with decreasing the nutrient content of soil. Loamy sand and clay loamy soils of the habitat had pH near neutral and EC varying from 0.43 to 0.90 dS m-1. It was concluded that the plant generally prefers the climate conditions with high temperature and high rainfall. In lower altitudes with more soil nutrients, there are more optimal conditions for the domestication and harvesting of S. hydrangea L. as a medicinal plant.