Investigation on resistance to drought and efficiency of water usage in two range species, Dactylis glomerata and Eragrostis curvula

Determination of water efficiency and resistance to drought in range plants are important factors that have essential role in selection of range development methods. As there is not any comprehensive study in resistance to drought, present research was done with selection of two range species. Selected species were two kinds of Gramineae, namely Dactylis glomerata and Eragrostis curvula. Some parameters such as used water, length, width and number of leaves, dry mass of leaves were studied. Obtained results showed that length and width of leaves were not under stress in irrigation periods, but number of leaves, dry mass of leaf and stem decreased under drought stress. Amount of decrease in Er.cu was less than Da.gl. Increment of irrigation periods, increased root growth rather than stem, but root growth in Da.gl was more than Er.cu. for production of dry matter, Da.gl. species has less water requirement and higher water usage efficiency in terms of amount of water usage. In terms of resistance to drought, Er.cu has more resistance rather than Da.gl. because of high water potential and lower witting point.