عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Background and objectives: Mechanical stresses such as wind stress can have an important role in adaptation and ecophysiology of plants. Generally, reducing plant height, leaf area reduction, increased stem diameter; fresh and dry weight loss is the most common reactions of plants against mechanical stresses of wind. Wind blowing could increase respiration, transpiration and reduce the water content, so changes the chemical composition of the cell wall and changes in hormone production of plants. Moreover, by increasing the intensity of the wind stress may be plants face faced with lodging. Lodging impede the flow of water and nutrients needed by plants and prevents the flow of assimilated substrate in photosynthesis to the developing roots or seeds, as a result, kernel filling is impaired. As well as, lodging increases relative humidity in a plant community that lead to mold growth and spread of disease. Many areas of Iran facing with intense winds at the wheat reproduction stage, and due to the erectness of its culm, lodging could be happened. There is enough variation in tolerance of wheat cultivars against wind, therefore the effects of mechanical stress caused by the wind blowing in two wheat cultivars; Rowshan (tall and old) and Sirvan (new and semi-dwarf) were evaluated.
Materials and methods: According to the above cases In order to evaluate the effects of mechanical stress caused by the wind blowing in the wheat, a three-factor factorial experiment in a completely randomized design with three replications was conducted in the experimental greenhouse of Ferdowsi University of Mashhad in 2014. The factors included the wind speed (5,10 and15meters per second) indifferent wind blowing duration (15, 30and45minutes) and two varieties of wheat; Roshan (tall and old) and Sirvan (new and semi-dwarf). For applying the treatments, pots were placed in a special chamber for mechanical wind stress in the same greenhouse.
Results: Results showed that the amount of plant height, plant leaf number, height of first node after treatment applying, plant dry weight, were decreased with the increase of wind speed and wind duration in both the Sirvan and Roshan cultivars, the decrease was less in the Sirvan compared to the Roshan. In both cultivars the greatest amount of above mentioned traits were observed in control treatment without wind. According to the experimental observations, it can be argued that the lodging caused by the wind leads to damage in the plant. It seems that regarding more resistance of the Sirvan against lodging, the cultivar was less affected by damage caused by the wind.
Conclusion: In general, Sirvan compared with Roshan, was less affected by wind stress and decreasing trend of the studied traits on Sirvan was less severe. Sirvan is a semi-dwarf cultivar that is resistant to lodging, that's why it seems that the cultivar was less impressed by increasing the speed and duration of the wind blowing.