Improvement of seed vegetative traits in Haloxylon ammodendron using biological and mechanical priming

The aim of this study was to evaluate the biological and mechanical methods of priming on improving germination characteristics and growth of Haloxylon ammodendron seedlings. Cultivation was performed in two parts of seedling tray and Petri dish in a completely randomized design in the Plant Physiology Laboratory of Semnan University. The biological treatments were Pseudomonas fluorescens, Azotobacter chroococcum, Bacillus megaterium, Azospirillum lipoferum, and Flavobacterium F-40. Ultrasonic device with 24 kHz wavelength application for 5 minutes was considered as mechanical priming treatment. Traits related to seed and seedling germination were measured. Result of analysis of variance in laboratory (Petri dish) showed significant differences for radicle length, ratio of  radicle  length to plumule  length, seedling growth, radicle and plumule fresh weight, and plumule dry weight (p<0.01). In the seedling tray, the effect of treatments was significant in radicle and plumule length, ratio of  radicle  length to plumule  length, radicle and plumule fresh weight, plumule dry weight, leaf freash and dry weight and leaf areas (p<0.01). Based on the results obtained from the comparison of means, ultrasonic treatment caused an increase (33%) in fresh weight of Haloxylon ammodendron radicle compared with the control in the seedling tray test. Azotobacter significantly increased radicle length (19%), ratio of  radicle  length to plumule  length (13%), seedling growth (10%), radicle fresh weight (23%), fresh weight (18%) and dry weight (18%) of plumule as compare to control in petri dish. In addition, Azotobacter increased radicle length (16%), ratio of  radicle  length to plumule  length (60%), leaf fresh weight (26%) and dry weight (68%), leaf area (172%) compare with the control in the seedling tray. Flavobacterium was able to increase the plumule length (21%) of Haloxylon ammodendron compared to the control in the seedling tray experiment. Azospirillum increased plumule fresh (65%) and dry weight (156%) of the plant in the seedling tray compared to the control. In general, according to the present results, the use of Azotobacter, Flavobacterium and Azospirillum bacteria was evaluated as a positive bio-priming treatment and can be used for propagation and production of Haloxylon ammodendron seedlings.