Mai M. A. Hassan¹, Fatima A. Hassan^2,

Dormancy is complex and seeds need a very specific pretreatment. The common pre- treatment that used to break dormancy is Acid which is dangerous and environment pollutant. So the aim of these experiments is to find substitute pre-treatments. Most of Sudanese seeds have physical dormancy. The coats are hard and need to be rupture or cracked to start germination process. Exposing the seeds to different series of low temperature (Liquid nitrogen) and high temperature (boiling water) may make cracks in the seeds coat. Seeds of Acacia seyal, Acacia nilotica, Cassia fistula, Acacia oerfota and Delonix regia were dipping in liquid nitrogen for 5 minutes and then dipping in hot water for 5 minutes. This were done 1, 2, 3, 4, 5 times and treated with electric burner as upper control and control without treatment. The results showed that the different treatments have not effected the germination percentage of Acacia nilotica, Cassia fistula, Acacia oerfota but the seeds of Acacia seyal and Delonix regia affected the germination percentage significantly. It gives percentage higher than un treated seeds. This result is promising in using the liquid nitrogen as pre-treatment instead of acid.

dormancy, germination percentage, liquid nitrogen, boiling water