Methods for dormancy overcoming of Spermacoce latifolia seeds

Abstract

Spermacoce latifolia presents wide dispersion in the Brazilian regions producing grains. The knowledge about the dormancy in weeds helps to understand the population dynamics and the efficient management. The present study had as objective to evaluate different treatments for overcoming dormancy of seeds. Nine treatments to overcome dormancy was used and the control, without treatment. After these, germination, germination first count and germination speed index tests were performed. A completely randomized design was used with four repetitions. Sandpaper 1' and 1% KNO3 shown the higher viability and vigor values. For G, FC and GSI, to the treatment seeds exposure to heat 60 °C there was no statistical difference comparing to the control, while the treatment seed exposure to heat 40 °C obtained results smaller than all other treatments, except those who used the H2SO4. For the seeds submitted to the treatments with H2SO4 for one and two minutes of immersion, there was no formation of seedlings. The treatments using the friction of seed in sandpapers for 1 minute and the immersion for 12 hours in KNO3 solution (1%) were efficient in overcoming dormancy of Spermacoce latifolia seeds. There are three possible causes of dormancy in this species: mechanical resistance of the cover to embryo growth, impermeability of the cover to the water and gas and imbalance between promoter and inhibitory substances to germination.

Keywords

• cover impermeability, germination promoter, speed germination, viability, weeds.