Individual- and Population-based Diversity in Restriction-modification Systems

In the grass genus Poa a wide variation in final leaf size and leaf growth rate exists. In this thesis leaf growth was analyzed at different levels. At the cellular level, inherent variation in leaf elongation rate and final leaf size was correlated to the length of the elongation zone and to meristematic cell production which, in turn, was caused by the size of the leaf basal meristem. A theoretical framework that links leaf elongation rate of individual leaves to whole plant relative growth rate is presented. Finally, it was found that contrasting Poa species respond differently to applications of the plant hormone ethylene (stimulation of leaf growth was found in two subalpine Poa species). The responsiveness to ethylene was associated with a different daily ethylene emission