Environmental factors affecting seed germination and seedling emergence of three Phalaris species

Abstract

Phalaris minor Retz., P. paradoxa L. and P. brachystachys Link. are prolific and competitive and considered as winter crops weeds. All three Phalaris species. The objective of the study was to obtain information about germination responses of P. minor, P. paradoxa and P. brachystachys to constant temperatures, drought and salt stresses, pH and seedling emergence to planting depth in laboratory and pot experiments. Interaction effect of constant temperatures and light regimes significantly influenced on seed germination of all three Phalaris species. With an increase in temperature from 10 °C to 30 °C, germination of all three Phalaris species was reduced. At 30 °C, 9.6% of P. minor seeds geminated, but no seed germination of P. paradoxa and P. brachystachys was observed. Both drought and salt stresses decreased germination of Phalaris species. Phalaris minor was able to germinate at higher levels of drought and salt stresses in comparison to P. paradoxa and P. brachystachys. Seeds of P. minor and P. paradoxa were germinated at pH ranges from 4 to 8, and all three Phalaris species germination was inhibited by pH higher than 8. Seedling emergence markedly affected by planting depth and Phalaris species interaction and reduced as planting depth increased. These results showed that germination of all three Phalaris species was affected by environmental conditions. Phalaris minor germinated over a wider range of environmental conditions than P. paradoxa and P. brachystachys, which explain why P. minor is more widespread within cropping systems.