; TeKrony, 2003 ). The controlled deterioration (CD) ( Powell and Matthews, 2005 ) and accelerated aging (AA) ( Hampton and TeKrony, 1995 ) tests have been successfully used to rank and predict relative field emergence potential of seed lots in various
longevity of seed lots ( Powell and Matthews, 2005 ; TeKrony, 2003 ). Several such tests have been used to indicate emergence potential and longevity in crop seeds among which controlled deterioration (CD) and accelerated aging (AA) are widely used
The accelerated aging vigor test subjects seeds to high temperatures (41°C) and relative humidity (about 100%) for short durations (usually 72 hours). These recommendations, however, have been developed for large-seeded agronomic crops and may be too severe for small-seeded flower crops that deteriorate rapidly during storage such as impatiens. We examined the effect of aging regime duration (48, 72, and 96 hours) and temperature (38 and 41°C) as well as relative humidity using three saturated salt solutions (KCl–87% RH, NaCl–76% RH, and NaBr–55% RH) on two commercial impatiens seed lots differing in seed vigor but not percentage germination. The greatest differences in percentage germination after 4 days were found among the treatments of 48 hours for KCl, 72 hours for NaCl, and 96 hours for NaBr. While any of these saturated salt solutions may be used in a commercial situation to determine impatiens seed vigor, we suggest that a total 7-day test period consisting of 72 hours aging at 41°C using saturated NaCl with germination being determined 4 days after aging is most convenient.
Abstract
Seeds of 2 cultivars of muskmelon (Cucumis melo L.) were subjected to accelerated aging at 45°C and 100% relative humidity (RH) for periods up to 288 hours. In general, longer periods of aging resulted in greater declines in seed quality as measured by laboratory, greenhouse, and field emergence and germination. Seeds of ‘Iroquois’ were more sensitive to aging than ‘Hale’s Best #36’. Significant declines in germination occurred prior to any significant increases in electrolytic leakage from decorticated seeds indicating that electrolytic leakage is not a suitable test for seed quality with muskmelon.
Damage and degradation of cellular proteins is observed during seed deterioration due to aging. L-isoaspartyl methyltransferase (EC 2.1.1.77) is an enzyme hypothesized to play a role in limiting and repairing aging-induced damage of proteins. Tomato seeds (Lycopersicon esculentum `New Yorker') were assayed for changes in L-isoaspartyl methyltransferase activity during accelerated aging and after osmotic priming. Accelerated aging of seeds for 1 to 4 days at 45°C and 100% humidity reduced germination from 94% to 71%, the mean time of germination (MTG) increased from 2.4 to 5.8 days and was accompanied by a correlative decrease in L-isoaspartyl methyltransferase activity R 2 = 0.90. Aged and untreated seeds were primed for 7 days at 20°C in darkness using aerated solutions of 3% KNO3 or polyethylene glycol 8000 (PEG) with equivalent osmotic potential (–1.25 MPa). Priming with KNO3 decreased the MTG but not germination percentage for untreated seeds. Priming did not affect L-isoaspartyl methyltransferase activity in untreated seeds but restored activity in aged seeds primed in KNO3 to levels near that of untreated seeds. Priming with PEG did not effectively improve the MTG or increase L-isoaspartyl methyltransferase activity. During germination, enzyme activity remained constant for 48 hours post-imbibition and then declined suggesting the enzyme was developmentally regulated and inactivated or degraded as radicle emergence occurred.
decreased with storage ( Taylor et al., 1998 ). Furthermore, priming may accelerate the effect of seed aging. For example, primed lettuce ( Lactuca sativa ) seeds aged faster than control seeds under 45 °C with 50% relative humidity (RH) conditions
development of normal seedlings under a wide range of sowing conditions ( McDonald, 1975 ). Tests are widely used in a number of agronomic and vegetable crops ( Hampton and TeKrony, 1995 ), but information in flower seeds is scarce. Accelerated aging is a well
genetic and environmental interactions during seed maturation and harvest ( Walters et al., 2010 ). Among these factors temperature and seed moisture content and relative humidity are well studied ( Ellis et al., 1992 ). Accelerated aging provides a simple
acrylic-accelerated aging container (156C, Hoffman Manufacturing, Inc.). We immediately assigned one of the trays at random to the container and transferred the container to an incubator (I-30-VL; Percival Scientific, Inc., Perry, IA) set at 41 °C with a
for the accelerated establishment treatment at all depths and putting green ages (data not shown). Branham et al. (2000) reported increased P levels in sand-based putting greens root zones after only 1 to 2 years of fertilizer applications. Although