Seedling Characteristics and Rates of Seed Reserve Utilization of Wilman Lovegrass and Kleingrass1

Abstract

The objective of this study was to determine why wilman lovegrass (Eragrostis superba Peyr.) has a greater shoot mass (P < 0.01) at 14 days postemergence than does kleingrass (Panicum coloratum L.). Caryopses of both species contain the same amount of starch, but wilman lovegrass caryopses contain more protein and P (P < 0.01). Wilman lovegrass had a greater shoot mass than kleingrass at 3 and 7 days postemergence. At 3 days after germination, wilman lovegrass caryopses contained less starch (P < 0.05) than kleingrass. At 6 days after planting, starch reserves were depleted in both species and protein and P contents of the caryopses residues were similar in both species, thus indicating the wilman lovegrass caryopses supplied more protein (or amino acids) and P to the growing shoot than did corresponding kleingrass caryopses. Respiration rates of caryopses of both grasses were similar after 1 day of imbibition, but respiration rates of 2‐ and 3‐day‐old wilman lovegrass seedlings were higher (P < 0.05) than rates of corresponding kleingrass seedlings. Wilman lovegrass had a greater nitrate reductase activity than kleingrass at 3 days after emergence (P < 0.05), although nitrite reductase activity and chlorophyll content were similar in both species. Selection for greater seedling vigor in kleingrass may result in genotypes with a) a faster rate of starch mobilization and utilization, and b) a higher starch, protein, and P content per caryopsis.