Quantity and Germinability of Oryzopsis hymenoides Seed in Lahontan Sands

Abstract

The location, quantity, and germinability of seed (caryopses) reserves of Oryzopsis hymenoides (R. & S.) Ricker in the soil were investigated at 4 locations in the Carson Desert of western Nevada. Numerous germinable seeds were recovered from the surface 15 cm of Lahontan sands. There was no clear relation between the number of seeds and depth of burial. On sites with pronounced dunes more seeds were found in the dune sands than in the interspaces. Seeds were recovered with and without evidence of sand abrasion of the indurate lemma and paleas. Seeds without wear marks were much more highly germinable (80%) than the more numerous seeds with wear marks (6%). The germinable seed reserve consisted of seeds that germinated without pretreatment when incubated at 20 degrees C; a much larger portion that required dissection to remove the indurate lemma and palea; and a fraction with embryo dormancy that had to be overcome with gibberellin enrichment of the germination substrate. Large numbers of opened, empty lemma and palea were found in the sands. Rodent enhancement of the germination of Oryzopsis hymenoides seeds appears to be a more valid hypothesis than mechanical abrasion from saltation.