GERMINATION OF SEEDS OF THREE SPECIES OF AGROSTIS

Abstract

Germination tests on seed of the 1939 crop of Agrostis stolonifera L. var. compacta Hartm., A tenuis Sibth., and A. canina L. were begun in September of the same year and carried through to May, 1940, with the object of studying the drift, with time, of germination capacity and germination speed under different conditions.Seeds of the three species proved to be highly light-sensitive but low light-requiring. Germination capacity was proportional to light intensity while germination speed was inversely proportional to light intensity. The possibility that excess of light (> 200 ft-c. for seven and one-half hours daily) might depress germination capacity was suggested. There was no significant difference, in their effect on germination, between Mazda and Fluorescent "Daylite" illumination at equal foot candle intensity.Potassium nitrate in 0.2% solution proved more effective than light in promoting germination in not fully germinating-ripe seeds but its use did not stimulate germination beyond the natural limits of fully ripe seed; thus its use in seed control laboratories is justified for these species. Its effect on the seed is clearly distinct, physiologically, from that of light.An interesting phenomenon was observed, consisting in a falling off in germination capacity accompanied by an absolute increase in germination speed during the period February–March.Seeds of these species fall into four classes. The interrelationships between these classes and changes within them and their connection with the February–March phenomenon are discussed in the text.