Exploiting heterogeneous environments: does photosynthetic acclimation optimize carbon gain in fluctuating light?

Abstract

Plants have evolved complex mechanisms to balance the efficient use of absorbed light energy in photosynthesis with the capacity to use that energy in assimilation, so avoiding potential damage from excess light. This is particularly important under natural light, which can vary according to weather, solar movement and canopy movement. Photosynthetic acclimation is the means by which plants alter their leaf composition and structure over time to enhance photosynthetic efficiency and productivity. However there is no empirical or theoretical basis for understanding how leaves track historic light levels to determine acclimation status, or whether they do this accurately. We hypothesized that in fluctuating light (varying in both intensity and frequency), the light-response characteristics of a leaf should adjust (dynamically acclimate) to maximize daily carbon gain. Using a framework of mathematical modelling based on light-response curves, we have analysed carbon-gain dynamics under various light patterns. The objective was to develop new tools to quantify the precision with which photosynthesis acclimates according to the environment in which plants exist and to test this tool on existing data. We found an inverse relationship between the optimal maximum photosynthetic capacity and the frequency of low to high light transitions. Using experimental data from the literature we were able to show that the observed patterns for acclimation were consistent with a strategy towards maximizing daily carbon gain. Refinement of the model will further determine the precision of acclimation.

Impact of spatio-temporal shade dynamics on wheat growth and yield, perspectives for temperate agroforestry

“….) to maintain a specific level of photosynthesis which is both related to the instantaneous environmental signal and the information from the past (Li et al, 2010;Murchie and Niyogi, 2011;Retkute et al, 2015). This raises questions about the potential to generalize results from our experimental design in which the shade treatments applied induced a sharp change in global radiation for the crop, whereas shade intensity increases progressively in a real agroforestry system.…”

“…Therefore, daily carbon gain and final yield cannot only be estimated from an average value of the global radiation over the whole cropping season. In fact, studies have highlighted the non-linear response of photosynthesis to light, particularly for plants growing in fluctuating and heterogeneous environments (Pearcy et al, 1996;Retkute et al, 2015). In fact, a developmental and dynamic acclimation process can takes place (i.e.…”

“…Photoacclimation could have occurred under our shade treatment, but to assess that correctly we would have needed complementary measurements such as photosynthetic rates. Furthermore, Murchie and Niyogi (2011) emphasizes that the photosynthetic adaptation (photoacclimation) of a plant to a new light environment takes place on a timescale of days, but uncertainty remains in fluctuating light environments (Retkute et al, 2015). In addition, several authors have shown that dynamic photoacclimation is highly dependent on species (Athanasiou et al, 2010;Murchie and Niyogi, 2011;Retkute et al, 2015).…”

“…Furthermore, Murchie and Niyogi (2011) emphasizes that the photosynthetic adaptation (photoacclimation) of a plant to a new light environment takes place on a timescale of days, but uncertainty remains in fluctuating light environments (Retkute et al, 2015). In addition, several authors have shown that dynamic photoacclimation is highly dependent on species (Athanasiou et al, 2010;Murchie and Niyogi, 2011;Retkute et al, 2015). Retkute et al (2015) argues that crop breeding programs should take acclimation traits into consideration in order to select shade tolerant cultivars.…”

Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops

“…A vast literature exists on optimization patterns of plant productivity through maximizing the efficiency of use of photosynthetically active radiation (PAR) (Zhu et al, 2010;Gitelson et al, 2015;Retkute et al, 2015), as well as water, phosphorus, and nitrogen (N) (Anten et al, 1995;Anten et al, 1996;Buckley et al, 2002;Vico et al, 2013;Hikosaka, 2014;Osada et al, 2014) at multiple scales, from individual leaves to entire canopies (Field et al, 1995;Goetz and Prince, 1999). Many of these studies analyze the patterns of individual components in isolation, while fewer evaluate the combination of a limited number of components for assessing synergistic relations and trade-offs (Karlsson, 1994;Herppich et al, 2002;Ali et al, 2012;Xu et al, 2013).…”