Iranian Journal of Seed Research

In order to investigate the effect of an electromagnetic field and ultrasonic waves on the seed germination of Cuminum cyminum that two separate experiments using a completely randomized design with four replications was conducted at Seed Science and Technology Laboratory of Faculty Agricultural Sciences, the Shahed University of Tehran in 2012. In the first experiment, for the seeds of zero, 10 and 30 min exposure to electromagnetic field intensity was 88 microTesla. In the second test (ultrasonic waves), seeds for zero, 2, 4, 6, 8 and 10 min exposure ultrasonic waves’ intensity were 40 and 59 kHz. The interaction between the electromagnetic field and the length had a significant effect on the traits of length, fresh weight and dry weight of root and shoot, length and weight of root to shoot ratio, percent and rate germination and mean germination time. In most of the studied traits showed that electromagnetic field causes a significant decrease in the number of traits so that the control (zero M.T) had the highest value. The interaction of Ultrasonic waves at the time had a significant effect of on the most traits. Maximum germination percentage (100%) for the treatment of 40 kHz with duration of 4 and 6 minutes and mean germination time was highest in control (10.76 days) and 59 kHz treatment duration of 2 and 4 min (respectively 11.01 and 10.75 days). Generally, Cuminum cyminum seeds responded positively to the use of ultrasonic waves (In contrast field) and germination index was significantly increased in this case.

For the purpose of evaluating the effect of chitosan on seed germination and some biochemical characteristics of the milk thistle herb in the conditions of salinity, an experiment was conducted as factorial in a completely randomized design (CRD) with three replications in the Laboratory of Seed Science and Technology of Shahed University, Tehran in 2015. Experimental factors comprised salinity levels (0, 4, 8 and 12 dS.m^-1) and different levels of Chitosan (0, 0.25, 0.5, 0.75 and 1 percent). The results showed that salt stress reduced germination percentage, germination coefficient, germination speed, weight and length vigor index, radical, plumule and seedling length and total biomass and increased mean germination time. Seed priming with chitosan up to 0.5% concentration increased germination coefficient, weighted index vigor and plumule length. The highest amounts of total chlorophyll and total protein were obtained in seed priming with 0.5% chitosan levels in zero salinity level (control). By increasing salinity levels, the activity level of catalase and peroxidase increased, so that the highest level of the activity of these two enzymes was obtained in the salinity level of 12 dS.m^-1 in pre-treatment with 0.5% Chitosan. The results showed that seed priming with chitosan of 0.5% could reduce harmful effects of salt stress on some traits of milk thistle seedlings and could even improve their growth.