“…These closed growth systems create growth conditions quite different from those encountered in the field (Kliss et al, 1996). Among the factors that vary are solid-support matrix, nutrient delivery and availability, relative humidity, photoperiod, accumulation of volatiles, and CO 2 partial pressure (Kliss et al, 1996). Such differing conditions have been associated with variability in composition compared to field grown crops (Alamazan et al, 1997;McKeehen et al, 1996;Steinberg et al, 2000;Wheeler, Mackowiak, et al, 1993, 1994.…”