Effect of halopriming treatment on seed germination and seedling emergence of Judas tree (Cercis siliquastrum L., Caesalpiniaceae) from Zanjan, Iran

The effect of seed halopriming with potassium nitrate on germination and emergence traits of Cercis siliquastrum L seeds, in two experiments were evaluated, one in the laboratory and the other in a greenhouse. The studies were a completely randomized design and 4 replications. The treatments included non-priming and halopriming with potassium nitrate at one of four concentrations (0, 100, 250, 500 and 750 mM) for 48 h, for all treatments the seeds were boiled in water per 24 h. The results showed that seed halopriming with KNO3 at the 750 mM concentration in the laboratory significantly increased several characteristics of germination. Emergence characteristics also were increased by pretreatment of seeds with potassium nitrate when planting in greenhouse. The highest emergence percentage (57%), speed of germination (1.54 seeds per day) emergence energy (44.8%) and lowest mean germination time (13.9 days) were showed in 100 mM treatment. The best halopriming level for seedling characteristics was detected in 100 mM KNO3. However,  haloprimed achenes resulted in maximum final emergence and shoot length, root length, collar diameter, shoot dry weight, root dry weight, number of leaves, leaf area and seedling quality index treated with primed techniques were increased and compared with non-prime treatment.   Key words: Afforestation, Cercis siliquastrum, germination, Potassium nitrate, regeneration, seedling quality index.