MATURATION OF WOODY-PLANTS - A REVIEW OF METABOLIC AND GENOMIC ASPECTS

The first part of this review consists of an evaluation of the bibliographic data on maturation studies in woody plants. It reports on the existing knowledge and the remaining questions relating to the events which control the transition phase between the juvenile and the mature phase, as well as the causes of the relative stability of these 2 phases. The physiology and molecular biology aspects are then considered for listing biochemical markers of maturation in woody plants. These markers occur as part of the primary and secondary metabolism (mineral and carbon nutrition, growth regulators, polyamines, phenolic compounds, peroxidase activity) and gene expression (nucleic acids, transcription, proteic synthesis). The results considered show that maturation is accompanied by variations in different - more or less linked - parameters. The discussion on the intervention of these parameters in the control of maturation and their use as maturation criteria shows that determination of the mature state should be multifactorial. These considerations point to a new "system" approach to physiology, based on the relations between the different metabolic systems of plants, and designed for the correlative study of tree development. This approach is intented to further the understanding of the phenomenon in question, and the determination of reliable maturation criteria.