Influence of Photoperiod on Phenylpropanoid Biosynthesis, and the Metabolism of These Derivatives in Xanthium Pensylvanicum

Abstract

Among living organisms, plants are the ones whose behaviour is most intimately associated with climatic conditions since they can neither move away from unfavourable conditions, nor regulate their internal temperatures. It is not surprising therefore that their growth and development is so strongly shaped by the environment. To prepare themselves for favourable or unfavourable climatic changes the majority of plants have become genetically sensitized through natural or artificial selection to seasonal changes in the relative lengths of daylight and darkness. This light sensitive "clock" allows plants to regulate periods of dormancy, growth and reproduction to times most suited to their survival. The response of plants to day length is termed photoperiodism.