Physiological adjustments of an invasive tree species to extreme hydrological events in a tropical seasonal wetland

• Published in: Trees (Berlin, West) Vol. 32; no. 5; pp. 1365 - 1375
• Main Authors: Dalmolin, Ândrea Carla, de Almeida Lobo, Francisco, Vourlitis, George Louis, Dalmagro, Higo José, Antunes Junior, Mario Zortéa, Rodriguez Ortiz, Carmen Eugenia
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2018; Springer Nature B.V
• Subjects: Agriculture; Biomedical and Life Sciences; Carbon dioxide; Carboxylation; Chlorophyll; Drought; Dry season; Electron transport; Flooding; Fluorescence; Forestry; Gas exchange; Hydrologic regime; Hydrology; Invasive plants; Leaves; Life Sciences; Nitrogen; Original Article; Parameters; Photochemicals; Photosynthesis; Photosynthetic pigments; Photosystem II; Physiological effects; Physiology; Pigments; Plant Anatomy/Development; Plant Pathology; Plant Physiology; Plant Sciences; Plant species; Proteins; Rainy season; Seasonal variations; Seasons; Trees; Water levels; Wetlands; Pantanal; Nitrogen partitioning; Fluorescence; Hyperseasonal savanna; Photosynthesis; Leaf gas exchange
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s00468-018-1718-8

Key message
We analyzed the response of
Vochysia divergens
Pohl trees to hydrological variation over seasons in a Brazilian wetland-based 26 physiological parameters. Dry
season conditions had a greater effect on the photosynthetic function than those in the wet season
.
Plants in seasonal wetlands are subject to large hydrological fluctuations and the physiological trade-offs that occur during these variations are still poorly understood. Within the Brazilian Pantanal, the largest tropical seasonal wetland in the world, the abundance of
Vochysia divergens
Pohl (Vochysiaceae) has been increasing and it forms mono-specific stands. The physiological performance of
V. divergens
trees to withstand seasonal variations in flooding and drought was evaluated to understand how the hydrological regime affects the species habitat and encourages new areas to be occupied. Individuals were evaluated for changes in their physiological parameters by means of CO
2
response curves, chlorophyll fluorescence, photosynthetic pigment and nitrogen (N) concentrations. Drought conditions caused reductions of 82, 64 and 80% of the maximum rate of CO
2
-saturated photosynthesis (
A
max m
), electron transport (
J
max m
), and carboxylation (
V
cmax m
) per unit leaf mass, an increase in leaf fluorescence (
F
0
: 27%) and non-photochemical quenching (
Φ
NPQ
: 18%), and a decrease in photochemical quantum yield of photosystem II (
Φ
PSII in
: 29%). The dry season also caused a significant reduction in leaf photosynthetic pigments and an increase in leaf N concentration, but most of the N was allocated away from carboxylation and electron transport proteins and toward leaf structure. Our data indicate that dry season drought caused a significant decline in biochemical properties associated with leaf gas exchange and an increase in allocation to leaf structure. The ability to rapidly shift to high photosynthesis as soon as water levels rise in the wet season may be critical for the growth and expansion of this species in the Pantanal.