Interaction Of Photosynthesis Research Articles

Stomatal evolution and plant adaptation to future climate.

Global climate change is affecting plant photosynthesis and transpiration processes, as well as increasing weather extremes impacting socio-political and environmental events and decisions for decades to come. One major research challenge in plant biology and ecology is the interaction of photosynthesis with the environment. Stomata control plant gas exchange and their evolution was a crucial innovation that facilitated the earliest land plants to colonize terrestrial environments. Stomata couple homoiohydry, together with cuticles, intercellular gas space, with the endohydric water-conducting system, enabling plants to adapt and diversify across the planet. Plants control stomatal movement in response to environmental change through regulating guard cell turgor mediated by membrane transporters and signaling transduction. However, the origin, evolution, and active control of stomata remain controversial topics. We first review stomatal evolution and diversity, providing fossil and phylogenetic evidence of their origins. We summarize functional evolution of guard cell membrane transporters in the context of climate changes and environmental stresses. Our analyses show that the core signaling elements of stomatal movement are more ancient than stomata, while genes involved in stomatal development co-evolved de novo with the earliest stomata. These results suggest that novel stomatal development-specific genes were acquired during plant evolution, whereas genes regulating stomatal movement, especially cell signaling pathways, were inherited ancestrally and co-opted by dynamic functional differentiation. These two processes reflect the different adaptation strategies during land plant evolution.

Mathematical Modeling of Photosynthesis and Analysis of Plant Productivity

Photosynthesis is the basis of the plant production process, which makes it extremely relevant to develop methods for evaluating and predicting it under various environmental conditions. The complexity of photosynthetic processes and the presence of numerous feedbacks in it make it important to develop complex approaches to its analysis, including mathematical modeling. This review analyzes mathematical models of photosynthetic processes at various levels (from processes in thylakoid membranes up to the level of the whole plant and ecosystem) and assesses potential ways to use them to study plant productivity. First of all, models describing the functioning of photosynthetic reaction centers (including primary charge separation, fluorescence, heat dissipation, etc.) are noted; they are widely used for interpreting experimental data in the analysis of photosynthetic processes in plants. The next group of models focuses on the description of electron transport by a photosynthetic electron transport chain or its parts (in particular, photosystem II). Such models can be used both for analyzing experimental data and for predicting damage to the photosynthetic apparatus under conditions of rapid changes in environmental conditions (for example, fluctuations in light intensity). Models that take into account the dark stage of photosynthesis rely on the idea of limiting stages for CO2 fixation or on detailed descriptions of Calvin–Benson cycle reactions. Models of this group can already be directly used to describe the production process. More complex models, in addition to describing photosynthesis, can also take into account the propagation of light and CO2 fluxes in the leaf and the interaction of photosynthesis with other physiological processes; this makes it possible to use such models to predict plant productivity under different conditions or under modifications of the photosynthetic apparatus. The review also analyzes “supra-organismal” photosynthetic models, which are based on fairly simple descriptions of photosynthetic processes and can be used to analyze productivity at the level of vegetation cover, natural or artificial ecosystems. In general, numerous mathematical models of photosynthesis at various levels are aimed at solving a wide range of research and practical problems. In particular, they can be potentially used to assess violations of crop productivity in unstable growing conditions or to optimize it in stable protected ground conditions. A promising direction for the development of photosynthetic modeling is the integration of individual models of various levels into a single photosynthesis modeling environment.

Global carbon cycle: Interaction of photosynthesis and earth crust processes

Global carbon cycle: Interaction of photosynthesis and earth crust processes

Global carbon cycle: Interaction of photosynthesis and earth crust processes

Global carbon cycle: Interaction of photosynthesis and earth crust processes

A model of canopy photosynthesis incorporating protein distribution through the canopy and its acclimation to light, temperature and CO2

The distribution of photosynthetic enzymes, or nitrogen, through the canopy affects canopy photosynthesis, as well as plant quality and nitrogen demand. Most canopy photosynthesis models assume an exponential distribution of nitrogen, or protein, through the canopy, although this is rarely consistent with experimental observation. Previous optimization schemes to derive the nitrogen distribution through the canopy generally focus on the distribution of a fixed amount of total nitrogen, which fails to account for the variation in both the actual quantity of nitrogen in response to environmental conditions and the interaction of photosynthesis and respiration at similar levels of complexity. A model of canopy photosynthesis is presented for C(3) and C(4) canopies that considers a balanced approach between photosynthesis and respiration as well as plant carbon partitioning. Protein distribution is related to irradiance in the canopy by a flexible equation for which the exponential distribution is a special case. The model is designed to be simple to parameterize for crop, pasture and ecosystem studies. The amount and distribution of protein that maximizes canopy net photosynthesis is calculated. The optimum protein distribution is not exponential, but is quite linear near the top of the canopy, which is consistent with experimental observations. The overall concentration within the canopy is dependent on environmental conditions, including the distribution of direct and diffuse components of irradiance. The widely used exponential distribution of nitrogen or protein through the canopy is generally inappropriate. The model derives the optimum distribution with characteristics that are consistent with observation, so overcoming limitations of using the exponential distribution. Although canopies may not always operate at an optimum, optimization analysis provides valuable insight into plant acclimation to environmental conditions. Protein distribution has implications for the prediction of carbon assimilation, plant quality and nitrogen demand.

Effects of drought stress and subsequent rewatering on photosynthetic and respiratory pathways in Nicotiana sylvestris wild type and the mitochondrial complex I-deficient CMSII mutant.

The interaction of photosynthesis and respiration has been studied in vivo under conditions of limited water supply and after consecutive rewatering. The role of the alternative (valt) and cytochrome (vcyt) pathways on drought stress-induced suppression of photosynthesis and during photosynthetic recovery was examined in the Nicotiana sylvestris wild type (WT) and the complex I-deficient CMSII mutant. Although photosynthetic traits, including net photosynthesis (AN), stomatal (gs) and mesophyll conductances (gm), as well as respiration (vcyt and valt) differed between well-watered CMSII and WT, similar reductions of AN, gs, and gm were observed during severe drought stress. However, total respiration (Vt) remained slightly higher in CMSII due to the still increased vcyt (to match ATP demand). valt and maximum carboxylation rates remained almost unaltered in both genotypes, while in CMSII, changes in photosynthetic light harvesting (i.e. Chl a/b ratio) were detected. In both genotypes, photosynthesis and respiration were restored after 2 d of rewatering, predominantly limited by a delayed stomatal response. Despite complex I dysfunction and hence altered redox balance, the CMSII mutant seems to be able to adjust its photosynthetic machinery during and after drought stress to reduce photo-oxidation and to maintain the cell redox state and the ATP level.

Analytical approaches to photobiological hydrogen production in unicellular green algae

Several species of unicellular green algae, such as the model green microalga Chlamydomonas reinhardtii, can operate under either aerobic photosynthesis or anaerobic metabolism conditions. A particularly interesting metabolic condition is that of “anaerobic oxygenic photosynthesis”, whereby photosynthetically generated oxygen is consumed by the cell’s own respiration, causing anaerobiosis in the culture in the light, and induction of the cellular “hydrogen metabolism” process. The latter entails an alternative photosynthetic electron transport pathway, through the oxygen-sensitive FeFe-hydrogenase, leading to the light-dependent generation of molecular hydrogen in the chloroplast. The FeFe-hydrogenase is coupled to the reducing site of photosystem-I via ferredoxin and is employed as an electron-pressure valve, through which electrons are dissipated, thus permitting a sustained electron transport in the thylakoid membrane of photosynthesis. This hydrogen gas generating process in the cells offers testimony to the unique photosynthetic metabolism that can be found in many species of green microalgae. Moreover, it has attracted interest by the biotechnology and bioenergy sectors, as it promises utilization of green microalgae and the process of photosynthesis in renewable energy production. This article provides an overview of the principles of photobiological hydrogen production in microalgae and addresses in detail the process of induction and analysis of the hydrogen metabolism in the cells. Furthermore, methods are discussed by which the interaction of photosynthesis, respiration, cellular metabolism, and H2 production in Chlamydomonas can be monitored and regulated.

The Photosynthetic Apparatus and Its Regulation in the Aerobic Gammaproteobacterium Congregibacter litoralis gen. nov., sp. nov

BackgroundThere is accumulating evidence that in some marine environments aerobic bacteriochlorophyll a-producing bacteria represent a significant part of the microbial population. The interaction of photosynthesis and carbon metabolism in these interesting bacteria is still largely unknown and requires further investigation in order to estimate their contribution to the marine carbon cycle.Methodology/Principal FindingsHere, we analyzed the structure, composition and regulation of the photosynthetic apparatus in the obligately aerobic marine gammaproteobacterium KT71T. Photoheterotrophically grown cells were characterized by a poorly developed lamellar intracytoplasmic membrane system, a type 1 light-harvesting antenna complex and a photosynthetic reaction center associated with a tetraheme cytochrome c. The only photosynthetic pigments produced were bacteriochlorophyll a and spirilloxanthin. Under semiaerobic conditions KT71T cells expressing a photosynthetic apparatus showed a light-dependent increase of growth yield in the range of 1.3–2.5 fold. The expression level of the photosynthetic apparatus depended largely on the utilized substrate, the intermediary carbon metabolism and oxygen tension. In addition, pigment synthesis was strongly influenced by light, with blue light exerting the most significant effect, implicating that proteins containing a BLUF domain may be involved in regulation of the photosynthetic apparatus. Several phenotypic traits in KT71T could be identified that correlated with the assumed redox state of growing cells and thus could be used to monitor the cellular redox state under various incubation conditions.Conclusions/SignificanceIn a hypothetical model that explains the regulation of the photosynthetic apparatus in strain KT71T we propose that the expression of photosynthesis genes depends on the cellular redox state and is maximal under conditions that allow a balanced membrane redox state. So far, bacteria capable of an obligately aerobic, photosynthetic metabolism constitute a unique phenotype within the class Gammaproteobacteria, so that it is justified to propose a new genus and species, Congregibacter litoralis gen. nov, sp. nov., represented by the type strain KT71T ( = DSM 17192T = NBRC 104960T).

Do photosynthetic and respiratory electron transport chains share redox proteins?

In purple nonsulfur bacteria and cyanobacteria, there is close interaction between the photosynthetic and respiratory electron transport chains, which share identical redox proteins. Recent findings that the thylakoid membranes of eukaryotic chloroplasts may have respiratory functions suggest that the interaction of photosynthesis and respiration may be a common feature of all photosynthetic cells.

Interaction of photosynthesis and respiration in Rhodospirillaceae: evidence for two functionally distinct b-c1 complex fractions

Flash-induced inhibition (on odd flashes) or reactivation (on even flashes) of respiration in photosynthetic bacteria has been interpreted formerly as resulting from a diversion of electrons from the respiratory pathway to the photosynthetic electron flow via cytochrome c 2 and re-injection of electrons in the respiratory pathway from the Q A Q B photoreduced acceptor (Vermeglio A. and Carrier, J.M. (1984) Biochim. Biophys. Acta 764, 233–238); the model implied that the photooxidation of cytochrome c 2 was strictly concomitant with the rise of respiration inhibition and that this inhibition was of large magnitude. These consequences are not verified experimentally. Instead, when correctly interpreting the oxygen signal kinetics obtained with a new electrode system bringing by centrifugation a thin layerof cells in close contact with a platinum electrode, it is found that the respiration inhibition exhibits kinetics very similar to those of the re-reduction of cytochromes c 1 + c 2 ; also,they are always of small magnitude. A new modelis proposed accounting for the above results: the respiratory and photosynthetic electron pathways are linked through the agency of the ubiquinone pool,not cytochrome c 2 . It is further specified that two populations of b-c 1 complex coexist, one associated with the reaction center and the other with the cytochrome oxidase; thesepopulations do not exchange freely, at least on a time-scale of a few seconds.

Interaction of photosynthesis, respiration and nitrogen fixation in cyanobacteria

Interaction of photosynthesis, respiration and nitrogen fixation in cyanobacteria

Factors involved in the amelioration of retarded symbiosis in Tinaroo glycine

Root nodules formed on Tinaroo glycine (Glycine wightii) were slow to pigment and begin fixing nitrogen. Various carbon and nitrogen compounds enhanced nodule pigmentation, the greening of the plants, and the rate of nitrogen fixation at 42 days. Of these inositol, glucose, ammonium nitrate (as both foliar and root applications) and coconut milk were most effective. Riboflavin, sodium glutamate and nodule infusion had little effect. There were no structural differences between nodules enhanced respectively by glucose and ammonium nitrate. Nodules on control plants showed slow development of the bacteroids and envelope membranes, with copious starch accumulation in uninvaded host cells. It was concluded that the retarded symbiosis in formed nodules was due initially to tardy nodule formation depleting the nitrogen reserves in the seeds before nitrogen fixation began. Because of the interaction of photosynthesis and nitrogen fixation, self-regeneration of nitrogen fixation in chlorotic plants was slow without an external stimulus. It is suggested that by selecting lines of the legume with larger seeds or by incorporating nitrogen in seed pellets the problem might be overcome.

The Interaction of Photosynthesis and Respiration and Its Importance for the Determination of 14C‐Discrimination in Photosynthesis

The Interaction of Photosynthesis and Respiration and Its Importance for the Determination of ¹⁴C‐Discrimination in Photosynthesis