Effects of soil flooding and changes in light intensity on photosynthesis of Eugenia uniflora L. seedlings

Abstract

The increased frequency of heavy rains as a result of global climate change can lead to flooding and changes in light availability caused by the presence of thick clouds. To test the hypothesis that reduction in light availability can alleviate the harmful effects of soil flooding on photosynthesis, the authors studied the effects of soil flooding and acclimation from high to low light on the photosynthetic performance of Eugenia uniflora. Seedlings acclimated to full sunlight (about 35 mol m -2 d -1 ) for 5 months were transferred to partial sunlight (about 10 mol m -2 d -1 ) and were either subjected to soil flooding or not flooded. Chlorophyll fluorescence was measured throughout the flooding period and leaf gas exchange was measured 16 days after flooding was initiated. Minimal fluorescence yield (Fo) was significantly higher and the quantum efficiency of open PSII centres (Fv/Fm) was significantly lower in flooded than in non-flooded plants in full sunlight. Sixteen days after flooding was initiated, stomatal conductance (gs sat ) and net photosyntheses expressed on a leaf area (A sat-area ), weight (A sat-wt ) and chlorophyll (A sat-Chl ) basis decreased in response to soil flooding. Flooding decreased stomatal conductance by similar amounts in full and partial sunlight, but A sat-area in partial and full sunlight was 3.4 and 16.8 times lower, respectively, in flooded than in non-flooded plants. These results indicate that changes from full to partial sunlight during soil flooding can alleviate the effects of flooding stress on photosynthesis in E. uniflora seedlings acclimated to full sunlight. The responses of photosynthesis in trees to flooding stress may be dependent on changes in light environment during heavy rains.

Biomass Accumulation in the Endangered Shrub Lindera melissifolia as Affected by Gradients of Light Availability and Soil Flooding

“…For example, stomatal closure is a commonly reported early response to soil flooding (Pezeshki 2001, Herrera et al 2008). This stomatal closure decreases CO 2 diffusion into the leaf (Farquhar and Sharkey 1982), leading to a decline in photosynthesis (Lavinsky et al 2007, Mielke and Schaffer 2011, Pimentel et al 2014, Oliveira and Gualtieri 2016, a decrease in photosynthate production, followed by a decline in biomass accumulation (Sena Gomes and Kozlowski 1980, Mielke et al 2003, Mielke and Schaffer 2010, Branco et al 2017.…”

Effects of Flooding and Shade on Survival, Growth, and Leaf Gas Exchange of Bottomland Tree Species across the Great Lakes Region (USA)

“…Excess light can result in chronic photoinhibition; this is the result of damage to the D1 polypeptide in the reaction center of photosystem II [23]. Additionally, sun leaves tend to have a lower chlorophyll content than shade leaves, which is exacerbated by flooding, further decreasing the photosynthetic capacity of the leaf and increasing the likelihood of photoinhibition [24,25]. In contrast, moderate shade can reduce the photoinhibition a flood-stressed plant experiences in full-light conditions and facilitate photosynthesis [26].…”

Flooding of tropical forests in central Amazonia: what do the effects on the photosynthetic apparatus of trees tell us about species suitability for reforestation in extreme environments created by hydroelectric dams?

“…In general, flooding causes stressful situations that result in typical symptoms such as stomatal closure, reduction of photosynthesis and reduction in pigment content (Gardiner and Krauss 2001;Oliveira and Joly 2010;Mielke and Schaffer 2011). Analysis of the pigment composition of leaves is important in plant ecophysiological studies, providing key information about physiological responses to environmental factors such as flooding (Kozlowski 2002;Lavinsky et al 2007;Mielke and Schaffer 2010;Parolin et al 2010;Duarte et al 2014).…”