Premium
Hydrothermal threshold models can describe the germination response of carrot ( Daucus carota ) and onion ( Allium cepa ) seed populations across both sub‐ and supra‐optimal temperatures
Author(s) -
Rowse HR,
FinchSavage WE
Publication year - 2003
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00707.x
Subject(s) - daucus carota , germination , allium , population , horticulture , hydrothermal circulation , base (topology) , botany , percentile , biology , chemistry , mathematics , paleontology , mathematical analysis , statistics , demography , sociology
Summary• The effect of temperature on the minimum (base) water potential for seed germination (Ψ b ) was investigated in Daucus carota and Allium cepa and then described in two hydrothermal threshold models. • Germination was recorded over a wide range of temperatures and water potentials. • At temperatures of 15°C and below the base water potential for germination of the 50th percentile (Ψ b (50)) was constant, but in both species, above a temperature ( T d ) around 16–19 °C, Ψ b (50) increased linearly with temperature. Hydrothermal time (HTT) and virtual osmotic potential (VOP) models were altered so that the effective base water potential (Ψ b ( G,T )) for any percentile of the seed population ( G ), above T d , was given by Ψ b ( G ) d + m ( T – T d ), where Ψ b ( G ) d is the uncorrected base water potential for that percentile. The coefficient m is the slope of the linear relationship between Ψ b ( 50 ) and temperature above T d . • Germination response to all temperatures and water potentials can be adequately described in both the HTT and VOP models by incorporating changes in Ψ b ( G,T ) with temperature.