Mathematical Description of the Influence of Temperature and Seed Quality on Imbibition by Seeds of Corn (Zea mays L.)
1972
Blacklow, W. M.
Imbibition by seeds of corn (Zea mays L.) was described by the equation W=f(t) — (α-W₀')/exp(kt) where W is the water content of the seed on a dry weight basis, f(t) = α ┼ bt and is the asymptote of the exponential curve where a is the asymptote at time t= 0 and b the slope, and W₀' is an adjusted initial water content. The rate constant k was shown to be related to the permeability of the seed to water, α to the initial water capacity of the seed, and b to the rate of change in the water capacity of the seed during imbibition which was related to elongation of the radicle and shoot. The initial water content, W₀, was linearly related to the relative humidity of the atmosphere in which the seed had equilibrated. The parameters k, b, and α were not significantly affected when W₀ varied from 2.0 to 13.9%. Both k and b increased exponentially with temperature with a Q₁₀ of 2.37 and 1.85, respectively, over the range 12 to 31C and 12 to 32.5, respectively; there was a sharp departure from the exponential relationship outside these ranges of temperature. The energy of activations of the exponential and linear phases of imbibition were 15.3 and 9.1 kcal/mole, respectively. The parameter α varied less dramatically with temperature and was fitted by a fourth order polynomial in temperature with a minimum at 26C. The parameters of the imbibition curve also were a function of age and variety of the seed. A survey of the literature showed that the equation for imbition could be used to describe imbibition of a wide range of seeds. The equation will be used in a mathematical model to predict germination and emergence of corn in a changing environment.
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