The effect of drought stress and selenium on some morphophysiological characteristics of Dragons head (Lallemantia iberica L.)

In order to investigate the effect of drought stress and different levels of selenium on growth and physiological characteristics of the Dragons head (Lallemantia iberica L.), a factorial experiment was conducted in a completely randomized design with three replications at Razi University Research Greenhouse. Experimental treatments consisted of different levels of humidity levels (full irrigation, 25%, 50% and 75% field capacity) and the second factor contained different concentrations of selenium (0, 5 and 10 mg L-1 sodium selenate). Foliar application of sodium selenate was performed in two stages. According to the results, drought stress had a negative effect on stem and leaf dry weight, inflorescence fresh weight, inflorescence length and leaf relative water content. Selenium increased shoot and leaf dry weight, inflorescence length and leaf relative water content. Under drought stress, selenium increased plant height, shoot number, stem fresh weight, leaf number and leaf fresh weight. Selenium increased biological yield, inflorescence dry weight, number of flowers, seed weight per plant, 1000-seed weight and seed yield. Selenium had a positive effect on stomatal conductance and chlorophyll fluorescence of leaves. As a result, foliar application of sodium selenate can overcome drought stress and prevents reduce in seed yield. The increase in seed yield in Dragons head may be related to increase in number of flowers per inflorescence, number of seeds per plant, seed weight per plant and 1000-seed weight. Therefore, under drought stress, foliar application of sodium selenate in two stages can prevent or reduce seed yield by reducing the effects of drought stress. Therefore, foliar application of 10 mg L-1 sodium selenate is recommended to reduce the effects of drought stress on the cultivation of Dragons head.