May photoinhibition be a consequence, rather than a cause, of limited plant productivity?

Abstract

Photoinhibition in leaves in response to high and/or excess light, consisting of a decrease in photosynthesis and/or photosynthetic efficiency, is frequently equated to photodamage and often invoked as being responsible for decreased plant growth and productivity. However, a review of the literature reveals that photoinhibited leaves characterized for foliar carbohydrate levels were invariably found to possess high levels of sugars and starch. We propose that photoinhibition should be placed in the context of whole-plant source-sink regulation of photosynthesis. Photoinhibition may represent downregulation of the photosynthetic apparatus in response to excess light when (1) more sugar is produced in leaves than can be utilized by the rest of the plant and/or (2) more light energy is harvested than can be utilized by the chloroplast for the fixation of carbon dioxide into sugars.

Using the quantum yields of photosystem II and the rate of net photosynthesis to monitor high irradiance and temperature stress in chrysanthemum (Dendranthema grandiflora)

“…decrease in Fv/Fm; [28] of chrysanthemum. Specifically, the highest level of irradiance had a significant negative effect on Fv/Fm at high temperatures.…”

“…Previous studies have shown that low irradiance protects the photosynthetic apparatus from the adverse effects of high temperature, while photoinhibition protects against both high irradiance and high temperature stress [7,27,28].…”

Jatropha curcasand Ricinus communisdisplay contrasting photosynthetic mechanisms in response to environmental conditions

“…Abiotic stresses are able to disturb this balance, and affect especially CO 2 assimilation due to stomatal and biochemical limitations (Adams III et al, 2013). The degree of preservation of adequate synchrony between light harvest, energy conversion in photosystems and CO 2 assimilation, under stress conditions, is speciesdependent and important to plant productivity (Athanasiou et al, 2010;Kramer and Evans, 2011;Murchie and Niyogi, 2011;Yamori et al, 2014).…”

“…Plants display a set of acclimation strategies to maintain adequate photosynthesis rates in response to abiotic stress-inducers such as high temperature, drought and high light levels (Liu and Huang 2008;Chaves et al, 2009;Gonzalez-Cruz and Pastenes, 2012). To reach their potential or maximum photosynthesis, plants employ a fine metabolic coordination involving several inter-related processes, especially a close balance between photochemical activity and Calvin cycle reactions (Goh at al., 2012).Abiotic stresses are able to disturb this balance, and affect especially CO 2 assimilation due to stomatal and biochemical limitations (Adams III et al, 2013). The degree of preservation of adequate synchrony between light harvest, energy conversion in photosystems and CO 2 assimilation, under stress conditions, is speciesdependent and important to plant productivity (Athanasiou et al, 2010;Kramer and Evans, 2011;Murchie and Niyogi, 2011;Yamori et al, 2014).…”

Interactions of shading conditions and irrigation regimes on photosynthetic traits and seed yield of soybean (Glycine max L.)

“…Stomatal restriction was reported as the main determinant of reduced photosynthesis under drought stress (Silva et al, 2013). The results showed that under limited irrigation treatment, the reduction in P n in different shading conditions did not coincide with reduction in C i , which indicate that the effect of shading treatments on photosynthesis under water stress conditions not only related to stomatal limitations in the leaves but also related to either damage in photosynthetic apparatus because of excess light absorption (Adams et al, 2013) or limited impairments in photophosphorylation, ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activity, and/or regeneration of ribulose-bisphosphate (Bota et al, 2004). Results demonstrated that the maximum photochemical efficiency of PSII (F v /F m ), probability of electron transport beyond QA (1-V J ) and the ratio of (1-V I )/ (1-V J ) which express the efficiency with which an electron from the intersystem electron carriers moves to electron acceptors in the reduced end at the PSI acceptor side, decreased due to limited irrigation, and this reduction was more pronounced under control treatment (no shade) compared with other shading treatments (Figure 3-a, b and c).…”