A mathematical model that uses Gaussian distribution to analyze the germination of Manfreda brachystachya (Agavaceae) in a thermogradient

Germination of nondormant seeds of Manfreda brachystachya (Agavaceae) was analyzed at temperatures ranging from 11-35 degrees C. Maximum germination (95%) occurred at 25 degrees C. An exponential sigmoid relationship was found between time and cumulative germination. Germination rate for every subpopulation (10-90% germination) was estimated by means of a normal distribution analysis. The kurtosis indicated the amplitude of the range of temperatures where the highest germination rates were concentrated, and the skew indicated sharply inhibitory temperatures in the range of temperatures used. Based on analysis of the normal distribution models for each subpopulation, we calculated a theoretical function which described germination rate over the temperature range considered: F(T,x) = A x exp[-B(C-1)(2)] where A is the function that describes germination rate for each subpopulation (characterized by the percentage [x] at optimal temperature