Ziziphus joazeiro Mart. is a Brazilian tree endemic to Caatinga and has been largely used in the Northeast of Brazil. Its seeds present tegument dormancy and this work aimed to evaluate pre-germinative treatments with concentrated sulfuric acid to break dormancy. Experimental design was completely randomized, with 9 treatments, i.e. 0, 30, 60, 90, 120, 150, 180, 210, and 240 min of immersion in concentrated sulfuric acid A.R. with three replicates of 50 seeds, in two experiments. In experiment 1, newly collected seeds were evaluated for 140 days. In experiment 2, 5-month stored seeds were evaluated for 100 days. Ziziphus joazeiro presents dormancy imposed by the endocarp that involves the seeds, and sulfuric acid should be used for 180 min on newly collected seeds and for 240 or 270 min on 5-month stored seeds in order to reach 80% emergence. Seed storage time may influence the germinative response, with faster emergence after 5-month storage.
Ziziphus joazeiro; dormancy; chemical pretreatment; scarification
