Abass Pourmeidani; Mohammad Reza Naeini; Hossein Bagheri; Ghader Karimi
Volume 18, Issue 1 , May 2011, , Pages 58-70
Abstract
The current research was conducted at Qom Fadak Greenhouse to study the effects of different salinity levels on physiologic and morphologic characteristics of three rangeland species (Hordeum fragilis, Agropyron desertorum and Agropyron elongatum). A factorial experimental design based on completely ...
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The current research was conducted at Qom Fadak Greenhouse to study the effects of different salinity levels on physiologic and morphologic characteristics of three rangeland species (Hordeum fragilis, Agropyron desertorum and Agropyron elongatum). A factorial experimental design based on completely Randomized Design with three replications was applied as the main factor included three rangeland species and the second factor included five salinity levels (0, 50,100,150 and 200 mMol NaCl). Salinity treatments were applied for 66 days and 27 variables were evaluated during the experiment. Results of analysis of variance showed significant differences among studied species and also different salinity levels. According to the results of means comparison test in 15 treatments (interaction effects of species and salinity), the highest RWC was observed in treatments of control (0 mM NaCl) and 50 mM NaCl in all three species and the lowest RWC was recorded at 200 mM NaCl in two Agropyron species. As a result, reduction in RWC was identified as plant response to salinity stress. The highest content of total chlorophyll was observed in control treatment and in two Agropyron species while the lowest content was recorded at 200 mM NaCl in all three species. With increase in salinity level up to 200 mM NaCl, soluble carbohydrate content increased. The highest percentage of proline was observed at 200mMol NaCl and in all three species. According to the results, threshold of salinity tolerance for Ag. elongatum, Ag. desertorum and Hordeum fragilis were determined 150, 100 and 50 mM NaCl respectively, and Ag. elongatum was identified as the most salt tolerant species in this research. A significant positive correlation was observed among growth parameters while correlation between growth parameters and carbohydrate content and percentage of proline was significantly negative. Total chlorophyll content showed a significant positive correlation with RWC and a significant negative correlation with WSD, soluble carbohydrates content and percentage of proline.
Mohammad ali Alizadeh; Ali ashraf Jafari
Volume 17, Issue 1 , September 2010, , Pages 115-126
Abstract
The effect of pre-cool temperature was studied on seed characteristics including: percent and speed of germination, seedling height, root/shoot length ratio, seedling weight, seedling dry/fresh weight ratio and vigour index in five ecotypes of Dactylis glomerata in laboratory and greenhouse condition. ...
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The effect of pre-cool temperature was studied on seed characteristics including: percent and speed of germination, seedling height, root/shoot length ratio, seedling weight, seedling dry/fresh weight ratio and vigour index in five ecotypes of Dactylis glomerata in laboratory and greenhouse condition. Beside of seed germination characteristics, some vegetative growth properties such as tiller number and leaf area were measured in greenhouse experiment. In laboratory condition, pre-cool germination temperature (4 °C) was applied by two weeks on seeds of ecotypes before standard germination test. In greenhouse, the seeds of five ecotypes were sownon pots with fluctuation temperatures 20±5°C during day and (5-12 °C) during night time. The 4 °C was used as base temperature for cold treatment on 15 and 35 days of seedling growth stage compared control. Data were collected and analyzed using factorial experiment method. Results showed, some ecotype like Gene bank had higher values for percent and speed of germination and vigour index than other ecotypes in both experimental conditions. The same ecotype had higher values for tiller number and leaf area than others in both control and cold treatment. It follows by two ecotypes of Hamadan and Karaj with high level of tiller number and leaf area in reaction by cold treatment compare with control in greenhouse. With regard to results, for all seed characteristics, tiller number and leaf area, Gene bank and then Karaj and Hamadan ecotypes were superior compared with other ecotypes.