Relationships between phenology and the remobilization of nitrogen, phosphorus and potassium in branches of eight Mediterranean evergreens

• Published in: The New phytologist 2005-10, Vol.168 (1), p.167-178
• Main Authors: Milla, R, Castro-Diez, P, Maestro-Martinez, M, Montserrat-Marti, G
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Arbutus unedo; Biological and medical sciences; Branches; Bupleurum fruticosum; Buxus sempervirens; Cistus laurifolius; Coniferophyta - growth & development; Coniferophyta - metabolism; Coniferophyta - physiology; Ecosystem; evergreens; Fundamental and applied biological sciences. Psychology; leaf development; leaf shedding; Leaves; Lonicera implexa; Mediterranean climate; Mediterranean Region; Models, Biological; Nitrogen; Nitrogen - metabolism; Nutrient nutrient interactions; nutrient remobilization; Phenology; phosphorus; Phosphorus - metabolism; physiological transport; Pistacia lentiscus; plant ecology; Plant growth; Plant nutrition; plant physiology; Plants; potassium; Potassium - metabolism; Quercus coccifera; Quercus ilex ssp. ballota; reproductive growth; seasonal variation; Seasons; shedding; Soil nutrients; Species Specificity; Synecology; Terrestrial ecosystems; Vegetative growth
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2005.01477.x

• Few studies have examined the effects of plant growth on nutrient remobilization in phenologically contrasting species. Here we evaluated the consequences of above-ground seasonality of growth and leaf shedding on the remobilization of nutrients from branches in eight evergreen Mediterranean phanaerophytes that differ widely in phenology. • Vegetative growth, flower bud formation, flowering, fruiting, leaf shedding, and the variations in nitrogen (N), phosphorus (P) and potassium (K) pools in branches throughout the year were monitored in each species. • Nitrogen and P remobilization occurred in summer, after vegetative growth and synchronously with leaf shedding. Despite the time-lag between growth and remobilization, the branches that invested more nutrients in vegetative growth also remobilized more nutrients from their old organs. Potassium remobilization peaked in the climatically harshest periods, and appears to be related to osmotic requirements. • We conclude that N and P remobilization occurs mainly associated with leaf senescence, which might be triggered by factors such as the replenishment of nutrient reserves in woody organs, the hormonal relations between new and old leaves, or the constraints that summer drought poses on the amount of leaf area per branch in summer.