The effect of various biological treatments on germination and some seedling indices of fennel (Foeniculum vulgare L.) under drought stress

One of the most important research fields in medicinal plants is the effect of environmental stresses on quantitative and qualitative yield of these plants and finding solutions for improving tolerance to these stresses. In order to study the influence of seed biopriming with Pseudomonas fluorescent and Trichoderma harzianum fungi on some germination and seedling indices of fennel (Foeniculum vulgare L.) under drought stress an experiment was conducted as factorial based on a completely randomized design with four replications. Experimental factors included bio-inoculation in nine levels (inoculation with four strains of PF2, PF16, PF56 and CHA0 of Pseudomonas fluorescent, and T13, T36, T39 and T43 strains of T. harzianum and non-primed (control)) and three levels of drought stress (0, -3 and -6 bar imposed by PEG6000). Seed germination and seedling characteristics were evaluated. Results showed that by increasing the osmotic potential levels, germination indices were decreased. In 0 bar, the highest germination percentage, root length and seedling length vigor index were obtained from CHA0 treated seeds and in three levels of stress, the highest germination rate, shoot length, dry weight seedling and seedling weight vigor index related to seed treatments by T39. Compared to non-inoculated seeds, CHA0 increased the root growth by 46, 51 and 51%, respectively, at osmotic potential levels of 0, -3, and -6 bar, respectively. According to the obtained results, it can be concluded using fungus and bacterial treatments can be causing to increasing of germination and seedling characteristic of fennel seeds in optimum and stress condition.