The effects of depth and duration of burial on seasonal germination, dormancy and viability of Galium aparine and Bifora radians seeds

Abstract

The effects of depth and duration of burial on seasonal germination, primary/secondary dormancy, and viability of Galium aparine and Bifora radians were studied in two experiments. The seeds of both species were buried at different depths with four replications in a split-plot design in the first experiment. The seeds were exhumed from the field at monthly intervals and germinated under suitable temperature conditions. In the second experiment, the seeds of both species were stored at 20degreesC and 50% relative humidity after harvest. Four replicates of seeds from each species were adjusted for germination tests at monthly intervals. Non-germinated seeds of either the first or the second experiment were treated with triphenyltetrazolium chloride in order to enhance the viability of seeds at monthly intervals until the end of the experiment. The seeds of G. aparine showed cyclic behaviour in the burial experiment. The germination percentage of B. radians seeds never exceeded 8% at all depths until 7 months after burial due to primary dormancy. Thereafter, the seeds showed typical cyclic behaviour with modest deviation. In both the species, the depth of burial strongly affected seed viability. In the dry storage conditions, the seeds of G. aparine and B. radians showed a high level of primary dormancy. The percentage viability of seeds declined depending on the duration of storage.