Germination of Echium plantagineum L. seeds submitted to dormancy overcoming and variations in temperature, light and depth of sowing

<div><p>Abstract: The objective of this study was to evaluate methods of overcoming dormancy, light regimens, temperature and depth of sowing variations in the physiological quality of Echium plantagineum seeds. The diaspores (agglutinated fruits from the seeds) were submitted to treatments using accelerated aging, potassium nitrate and gibberellic acid to overcome dormancy. A 7 x 2 factorial design was used to evaluate the temperatures (5, 10, 15, 20, 25, 30 and 35 °C) and light regimens (presence or absence of light). A 6 x 2 factorial design was used for sowing depth (0, 1, 2, 3, 4 and 5 cm) and soil coverage (presence or absence of straw). In all experiments, a completely randomized design with four replicates of 50 diaspores was used. The main evaluations were germination, first germination count, germination speed index and emergence. The seeds showed dormancy, which was overcome by the immersion of the diaspores in potassium nitrate and gibberellic acid. The ideal temperature for germination was 20 °C, showing greater germination in the presence of light, considered as preferentially positively photoblastic. The highest germination percentage occurred when the diaspores were positioned on the soil surface in the presence of straw.</p></div>