Function representing the strategy of plants adjusting their roots:shoots
ratios during the season.
Arguments
- ST
float Temperature sum in degree(C)-days.
- minSEA
float < 1. Minimum value of SEA.
- maxSEA
float > 1. Maximum value of SEA.
- ST1
float Temperature sum after which SEA declines from the maximum
plateau.
- ST2
float Temperature sum after which SEA reaches and remains at
its minimum.