Effects of Storage and Burial on Germination Responses of Encapsulated and Naked Seeds of Turnipweed (Rapistrum rugosum) to Light

Abstract

Information on the germination and viability of turnipweed seeds could be helpful in developing appropriate management strategies for this weed. Therefore, experiments were conducted to investigate the effects of light, storage conditions, duration of storage or burial, and seed type (naked, i.e., fruit wall was removed and encapsulated in siliques) on germination and viability of turnipweed. The naked and encapsulated seeds (fruit) were kept under five different storage conditions, including dry storage at 25 ± 2 C and 3 ± 1 C and outdoor environments (soil depths of 10, 20, and 40 cm). All seeds were retrieved every 2 mo and tested for germination in light and darkness. At each exhumation date, nongerminated seeds were treated with triphenyltetrazolium chloride to test their viability. The germination of seeds liberated from siliques (85%) was markedly greater than that of seeds in intact siliques (20%). The germination response of naked and encapsulated seeds to light varied between storage conditions and through time. Under indoor conditions (room and cold), both seed types had greater germination percentages in dark on most occasions than those in light. On the contrary, the germination of siliques buried at soil depths of 20 or 40 cm was considerably stimulated by light. Under indoor conditions, the percent viability of both seed types only declined marginally, whereas seeds buried in soil showed high rates of mortality. Seeds in intact siliques persisted longer under either indoor or outdoor conditions than naked seeds.