Effect of dust on the growth and physiological traits of wild mustard (Sinapis arvensis L.) and wild barley (Hordeum spontaneum [K. Koch] Thell.) in the greenhouse conditions

To evaluate the effect of dust on the growth and physiological properties of wild mustard (Sinapis arvensis) and wild barley (Hordeum spontaneum), a greenhouse experiment was conducted in the Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran during 2016 and 2017. The experiment was repeated twice in the same greenhouse condition with eight weeks' interval. The pots were arranged in a completely randomized design with four replications. Analysis of variance was done as factorial split in time. The factorial combination of two weeds species (wild mustard and wild barley), and three dust concentrations (0, 750 and 1500 µg m-3) were as the main factors, and four harvest times (8 leaves (BBCH-18), beginning of stem elongation (BBCH-30), beginning of flowering (BBCH-61) and beginning of fruit developing (BBCH-71)) were as the sub-factors. Results indicated that total fresh and dry weights were reduced with increasing the amount of dust. At the BBCH-71 growth stage, 750 and 1500 µg m-3 dust concentrations reduced the total dry weight of both species up to 30 and 48%, respectively. 1500 µg m-3 dust concentration decreased both photosynthesis and transpiration rates by approximately 50%.