Facing Shortage or Excessive Light: How Tropical and Subtropical Trees Adjust Their Photosynthetic Behavior and Life History Traits to a Dynamic Forest Environment

LOUIS S. SANTIAGO; ZHANG, Y.-J.,; GOLDSTEIN G,F; AVALOS GERARDO; CAMPANELLO PI; VILLAGRA, M

Tropical Tree Physiology. Adaptations and Responses in a Changing Environment.

Springer

Año: 2016; p. 319 - 337

Abstract Light is critical for plant establishment, growth, and survival in wettropical forests. The objective of this chapter is to analyze paradigms of photosynthetic performance and life history traits of tropical forest trees to contrastinglight environments across the forest floor, gaps and upper canopy. Physiologicaland morphological plasticity as well as genetically fixed adaptive traits are analyzed, including leaf optical properties and photoprotection from high irradiance.Photosynthetic adaptations to contrasting light environments of closely relatedspecies are discussed. This approach has the advantage among comparative studiesof adaptations across species in that genetic relationships among species are known.Species-specific variations in maximum photosynthetic rates, which reflect thedegree of adaptation to growth irradiance, are shown to be gradual, suggesting thatclassification into two distinct functional groups in terms of light requirements issomewhat arbitrary. Trees growing in gaps or in the upper canopy rely strongly onbiochemical mechanisms to dissipate excess energy and to avoid damage to thelight reaction centers and photosystems. Consistent with their high photosyntheticcapacity, light demanding species are capable of plastic changes in hydraulic architecture, such as increases in hydraulic conductivity under high irradiance, whichmakes them more competitive in open habitats.