Effects of temperature and seed coat treatments on germination of sweet pea

Tests on seeds of sweet pea (Lathyrus odoratus L.) were set up to examine responses to temperature during germination and to investigate the effects of mechanical and chemical treatments on the permeability of the seed coat to water.Optimum temperatures for germination occurred at about 21 °C, and higher temperatures resulted in the production of fewer seedlings. Although temperatures below c. 15 °C also reduced the numbers of seeds which germinated, even at 2 °C more than 50 % germinated within 60 days.Treatments with concentrated sulphuric acid or the mechanical removal of part of the seed coat by filing greatly increased permeability to water and under some conditions improved germination responses. Filing, followed by exposure to excess free water, reduced germination rates, possibly as a result of loss of solutes from the seed during imbibition.