Physical and germinative characterisation of the seeds of native and naturalised pasture species in southern Chile II: Anthoxanthum odoratum, Holcus lanatus, Poa pratensis y Lotus uliginosus

Abstract

The physical and germinative seed features of naturalised pasture species Anthoxanthum odoratum, Holcus lanatus, Poa pratensis, Lotus uliginosus Dactylis glome rata and Trifolium repens, collected from pastures of Southern Chile, were studied.
The germination test was conducted under controlled temperature, light and humidity conditions. The duration was variable depending on the requirements of each species. Simultaneously, two seed pretreatments for braking latency were evaluated (potassium nitrate solution at 0,2% applied at the beginning of germination test and seed cooling at 4°C for 7 days).
During the respective evaluation period the germinative dynamic of each specie was studied in relation each pretreatment. At the end of the germination period the following parameters were evaluated: normal seedlings, abnormal seedlings, dead seeds, latent seeds, hard seeds (in legumes specie) and viable seeds. The latent seeds were subjected to tetrazolium in order to determine viability and hard seeds were scarified.
Among grasses, Holcus lanatus (79,7%) and Poa pratensis (80,4%) showed a similar germinative performance in relation to the control specie Dactylis glomerata (80,5%), on the other hand, Anthoxanthum odoratum showed the lower germinative development (71,3%). The legume specie Lotus uliginosus and Trifolium repens showed very low percentages of germination (14,3 y 11%, respectively), as a consequence of their high levels of hard seeds.
Among the pregerminative treatments tested, potassium nitrate showed a favourable effect over Holcus lanatus germination. Cooling pretreatment, nevertheless showed a adverse effect over Dactylis glomerata and a favourable effect over Holcus lanatus.