Lq. Hung et al., Constant, fluctuating and effective temperature and seed longevity: a tomato (Lycopersicon esculentum Mill.) exemplar, ANN BOTANY, 88(3), 2001, pp. 465-470
Tomato seeds with a moisture content of 16.4 % were stored hermetically at
one of five constant temperatures (10, 20, 30, 40, 50 degreesC) or in one o
f nine alternating temperature (24 h/24 h) regimes (10/30, 10/40, 10/50, 20
/30, 20/40, 20/50, 30/40, 30/50, 40/50 degreesC) for up to 224 d. In each r
egime, seed survival conformed to cumulative negative normal distributions
and all 14 survival curves could be constrained to a common origin. Estimat
es of the constants C-H and C-Q of the viability equation determined at con
stant temperatures were 0.0346 (s.e. 0.0058) and 0.000401 (s.e. 0.000096),
respectively. The effective temperature for seed survival of each alternati
ng temperature regime was always much higher than the mean. Tomato seeds we
re also stored hermetically at 15.9 % moisture content at 40 degreesC for 0
, 7, 14, 21 or 28 d before transfer to 50 degreesC. This investigation show
ed that the standard deviation of the subsequent survival curves at 50 degr
eesC was unaffected by the duration of previous storage at 40 degreesC. The
results of both investigations were consistent with the hypothesis that lo
ss in probit viability is solely a function of the current storage environm
ent, with no effect of change in temperature per se. The application of the
viability equation to seed survival in fluctuating environments was valida
ted against independent observations for rice in uncontrolled storage condi
tions. (C) 2001 Annals of Botany Company.