After-ripening and aging as influenced by anoxia in switchgrass (Panicum virgatum L.) seeds stored at 60 degrees C

Elevated storage temperatures can accelerate both after-ripening and aging of seeds. This research aimed to see if anoxic conditions might "disconnect " the two processes, allowing after-ripening of dry switchgrass (Panicum vi rgatum L.) seeds to proceed while holding aging in check under physiologica lly Very high temperature (60 degrees C). Seedlots were adjusted to an init ial moisture content (MC) of 55 g kg(-1) and stored in sealed jars that wer e first vacuumed and flushed with air or 99.99% nitrogen. To further ensure an air-free environment during a second storage experiment with initial MC of 75 g kg(-1), jars filled with nitrogen were sealed inside plastic bags flushed with nitrogen. Germinability increased from 4% to about 80% in 32 d for seeds stored at 55 g kg(-1) MC whether in air or nitrogen. After 32 d storage in air or nitrogen, about one-half to one-third of seedlings were a bnormal. Germinability of seeds with 75 g kg(-1) MC increased from 4% to 65 % after 13 d at 60 degrees C in nitrogen. Germinability of the seeds at 75 g kg(-1) MC in the air-flushed treatment increased to 58% by 7 d but decrea sed to 26% by 13 d. In switchgrass, less aging occurred in seeds stored in nitrogen with MC of 75 g kg(-1), but after-ripening seemed to occur readily in either air or nitrogen at both MC.