Impact of Presowing Seed Treatments, Temperature and Seed Coats on Germination of Velvet Bundleflower

Abstract

Seeds with both smooth and rough, apparently scarified, seed coats occur in harvested samples of velvet bundleflower (Desmanthus velutinus Scheele.). To determine the degree of scarification, germination responses of rough and smooth seeds were investigated at 4 night/day temperature regimes, 5/15 degrees C, 10/20 degrees C, 15/25 degrees C, and 20/30 degrees C with a 12-hour photoperiod during the high temperature and with 3 seed treatments, cutting, acid scarification and hot water soak. Rough seed coats appear to be caused by peeling of the cuticular layer on the seed surface. Moisture was imbibed more rapidly by smooth seeds, and total germination of smooth seeds was 31% without treatment, 4 times greater than rough seed germination. Treatments increased germination of smooth seeds two- to four- fold and rough seeds over 10-fold. After treatment, rough seeds germinated significantly (P<.05) better than smooth seeds at all temperature regimes except 5/15 degrees C. Cut and scarified seeds generally germinated more rapidly than water-treated seeds, but total germination was similar for all treatments at warmer temperatures. Germination was only 31% at 5/15 degrees C.