Early Growth in Annual and Perennial Ryegrass1

Abstract Two stages of early growth are described for Lolium temulentum, an annual, and L. perenne, a perennial species of ryegrass. The first stage, from time of sowing to about the ninth day, is one of rapid growth. The second stage, which may be indicative of the rest of the growing season, is one of slower growth in which the annual has a higher photosynthesis and respiration rate, a larger root system, and a lower leaf starch content than does the perennial. Chlorophyll and water content of leaves of the two species are similar. The annual germinates earlier.