scholarly journals Differences in isoprenoid-mediated energy dissipation pathways between coastal and interior Douglas-fir seedlings in response to drought

2019 ◽  
Vol 39 (10) ◽  
pp. 1750-1766 ◽  
Author(s):  
Laura Verena Junker-Frohn ◽  
Anita Kleiber ◽  
Kirstin Jansen ◽  
Arthur Gessler ◽  
Jürgen Kreuzwieser ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Intraspecific Variation ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Douglas Fir ◽  
Future Climate ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
Climate Conditions ◽  
Pool Sizes

ABSTRACT Plants have evolved energy dissipation pathways to reduce photooxidative damage under drought when photosynthesis is hampered. Non-volatile and volatile isoprenoids are involved in non-photochemical quenching of excess light energy and scavenging of reactive oxygen species. A better understanding of trees’ ability to cope with and withstand drought stress will contribute to mitigate the negative effects of prolonged drought periods expected under future climate conditions. Therefore we investigated if Douglas-fir (Pseudotsuga menziesii(Mirb.)) provenances from habitats with contrasting water availability reveal intraspecific variation in isoprenoid-mediated energy dissipation pathways. In a controlled drought experiment with 1-year-old seedlings of an interior and a coastal Douglas-fir provenance, we assessed the photosynthetic capacity, pool sizes of non-volatile isoprenoids associated with the photosynthetic apparatus, as well as pool sizes and emission of volatile isoprenoids. We observed variation in the amount and composition of non-volatile and volatile isoprenoids among provenances, which could be linked to variation in photosynthetic capacity under drought. The coastal provenance exhibited an enhanced biosynthesis and emission of volatile isoprenoids, which is likely sustained by generally higher assimilation rates under drought. In contrast, the interior provenance showed an enhanced photoprotection of the photosynthetic apparatus by generally higher amounts of non-volatile isoprenoids and increased amounts of xanthophyll cycle pigments under drought. Our results demonstrate that there is intraspecific variation in isoprenoid-mediated energy dissipation pathways among Douglas-fir provenances, which may be important traits when selecting provenances suitable to grow under future climate conditions.

Light energy dissipation in Quercus ilex resprouts after fire

2000 ◽  
Vol 27 (2) ◽  
pp. 129 ◽  
Author(s):  
Isabel Fleck ◽  
Xavier Aranda ◽  
Bouchra El Omari ◽  
Jon Permanyer ◽  
Anunciación Abadía ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Quercus Ilex ◽  
Photosynthetic Capacity ◽  
Leaf Age ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
High Irradiance ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Sink Strength

Holm oak (Quercus ilex) plants that have resprouted after fire have higher photosynthetic capacity than control plants in intact vegetation. In this study, branches detached from forest plants were fed with dithiothreitol (DTT) in the laboratory to inhibit zeaxanthin production and thus reduce the dissipation of light energy as heat. This allowed us to test the hypothesis that plants with greater photosynthetic capacity, and therefore greater photo-chemical sink strength, would suffer a lower reduction in photochemical efficiency under stressful conditions. Greater rates of photochemistry in resprouts, which exhibited increased photosynthesis (A), leaf conductance (g), quantum yield of PSII (ΔF/Fm′) and photochemical quenching (qP), were related to lower non-radiative dissipation of excess energy as indicated by 1 – (Fv′/Fm′). However, the fraction of energy remaining of that used in photo-chemistry or dissipated thermally in the PSII antennae was similar in resprouts and controls and was not affected by DTT, especially under high irradiance conditions. Zeaxanthin involvement in PSII protection operated in resprouts and controls since DTT induced the same kind of response (NPQ decrease) but was lower in resprouts. These chloro-phyll fluorescence results suggest the participation of some additional mechanism for energy dissipation. Light capture characteristics of the photosynthetic apparatus did not differ between resprouts and controls, and leaf age did not play a determining role in the differences observed.

scholarly journals Photosynthetic performance and photosynthesis-related gene expression coordinated in a shade-tolerant species Panax notoginseng under nitrogen regimes

2020 ◽  
Author(s):  
Jin-Yan Zhang ◽  
Zhu Cun ◽  
Jun-Wen Chen
Keyword(s):  
Photosynthetic Capacity ◽  
Calvin Cycle ◽  
Photosynthetic Apparatus ◽  
Panax Notoginseng ◽  
Photochemical Quenching ◽  
Light Reaction ◽  
Anatomic Structure ◽  
Tolerant Species ◽  
Expression Of Genes ◽  
Shade Tolerant Species

Abstract Background: Nitrogen (N) is an essential component of photosynthetic apparatus. However, the mechanism that photosynthetic capacity is suppressed by N is not completely understood. Photosynthetic capacity and photosynthesis-related genes were comparatively analyzed in a shade-tolerant species Panax notoginseng grown under the levels of low N (LN), moderate N (MN) and high N (HN). Results: Photosynthetic assimilation was significantly suppressed in the LN- and HN-grown plants. Compared with the MN-grown plants, the HN-grown plants showed thicker anatomic structure and larger chloroplast accompanied with decreased ratio of mesophyll conductance (gm ) to Rubisco content (gm /Rubisco) and lower Rubisco activity. Meanwhile, LN-grown plants displayed smaller chloroplast and accordingly lower internal conductance (gi ). LN- and HN-grown individuals allocated less N to light-harvesting system (NL ) and carboxylation system (NC ), respectively. N surplus negatively affected the expression of genes in Car biosynthesis ( GGPS , DXR , PSY , IPI and DXS ). The LN individuals outperformed others with respect to non-photochemical quenching. The expression of genes ( FBA, PGK, RAF2, GAPC, CAB, PsbA and PsbH ) encoding enzymes of Calvin cycle and structural protein of light reaction were obviously repressed in the LN individuals, accompanying with a reduction in Rubisco content and activity. Correspondingly, the expression of genes encoding RAF2 , RPI4 , CAB and PetE were repressed in the HN-grown plants. Conclusions: LN-induced depression of photosynthetic capacity might be caused by the deceleration on Calvin cycle and light reaction of photosynthesis, and HN-induced depression of ones might derive from an increase in the form of inactivated Rubisco.

scholarly journals Photosynthetic performance and photosynthesis-related gene expression coordinated in a shade-tolerant species Panax notoginseng under nitrogen regimes

2019 ◽  
Author(s):  
Jin-Yan Zhang ◽  
Zhu Cun ◽  
Jun-Wen Chen
Keyword(s):  
Photosynthetic Capacity ◽  
Calvin Cycle ◽  
Photosynthetic Apparatus ◽  
Panax Notoginseng ◽  
Photochemical Quenching ◽  
Light Reaction ◽  
Anatomic Structure ◽  
Tolerant Species ◽  
Expression Of Genes ◽  
Shade Tolerant Species

Abstract Nitrogen (N) is an essential component of photosynthetic apparatus. However, the mechanism that photosynthetic capacity is suppressed by N is not completely understood. Photosynthetic capacity and photosynthesis-related genes were comparatively analyzed in a shade-tolerant species Panax notoginseng grown under the levels of low N (LN), moderate N (MN) and high N (HN). Photosynthetic assimilation was significantly suppressed in the LN- and HN-grown plants. Compared with the MN-grown plants, the HN-grown plants showed thicker anatomic structure and larger chloroplast accompanied with decreased ratio of mesophyll conductance (gm ) to Rubisco content (gm /Rubisco) and lower Rubisco activity. Meanwhile, LN-grown plants displayed smaller chloroplast and accordingly lower internal conductance (gi ). LN- and HN-grown individuals allocated less N to light-harvesting system (NL ) and carboxylation system (NC ), respectively. N surplus negatively affected the expression of genes in Car biosynthesis ( GGPS , DXR , PSY , IPI and DXS ) and non-net carboxylative process (CEF-PSI). The LN individuals outperformed others with respect to non-photochemical quenching. The expression of genes ( FBA, PGK, RAF2, GAPC, CAB, PsbA and PsbH ) encoding enzymes of Calvin cycle and structural protein of light reaction were obviously repressed in the LN individuals, accompanying with a reduction in Rubisco content and activity. Correspondingly, the expression of genes encoding RAF2 , RPI4 , CAB and PetE were repressed in the HN-grown plants. LN-induced depression of photosynthetic capacity might be caused by the deceleration on Calvin cycle and light reaction of photosynthesis, and HN-induced depression of ones might derive from an increase in the form of inactivated Rubisco and the deprivation of photoprotection.

scholarly journals Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 721
Author(s):  
Magdalena Trojak ◽  
Ernest Skowron
Keyword(s):  
Photosynthetic Pigments ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Light Spectrum ◽  
Negative Effects ◽  
Tomato Plants ◽  
Lower Amplitude ◽  
Non Photochemical Quenching

Photosynthetic pigments of plants capture light as a source of energy for photosynthesis. However, the amount of energy absorbed often exceeds its utilization, thus causing damage to the photosynthetic apparatus. Plants possess several mechanisms to minimize such risks, including non-photochemical quenching (NPQ), which allows them to dissipate excess excitation energy in the form of harmless heat. However, under non-stressful conditions in indoor farming, it would be favorable to restrict the NPQ activity and increase plant photosynthetic performance by optimizing the light spectrum. Towards this goal, we investigated the dynamics of NPQ, photosynthetic properties, and antioxidant activity in the leaves of tomato plants grown under different light qualities: monochromatic red (R), green (G), or blue (B) light (L) at 80 µmol m−2 s−1 and R:G:B = 1:1:1 (referred to as the white light (WL)) at 120 µmol m−2 s−1. The results confirm that monochromatic BL increased the quantum efficiency of PSII and photosynthetic pigments accumulation. The RL and BL treatments enhanced the NPQ amplitude and showed negative effects on antioxidant enzyme activity. In contrast, plants grown solely under GL or WL presented a lower amplitude of NPQ due to the reduced accumulation of NPQ-related proteins, photosystem II (PSII) subunit S (PsbS), PROTON GRADIENT REGULATION-LIKE1 (PGRL1), cytochrome b6f subunit f (cytf) and violaxanthin de-epoxidase (VDE). Additionally, we noticed that plants grown under GL or RL presented an increased rate of lipid peroxidation. Overall, our results indicate the potential role of GL in lowering the NPQ amplitude, while the role of BL in the RGB spectrum is to ensure photosynthetic performance and photoprotective properties.

scholarly journals EFFECTS OF SUCROSE ON METABOLIZE POOL SIZES AND RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE/OXYGENASE ACTIVITY IN STRAWBERRY PLANTLETS CULTIVATED IN VITRO

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 250b-250
Author(s):  
Chafik Hdider ◽  
Yves Desjardins
Keyword(s):  
Time Course ◽  
Photosynthetic Capacity ◽  
Tight Binding ◽  
Net Photosynthesis ◽  
Negative Effects ◽  
Slow Increase ◽  
Bisphosphate Carboxylase ◽  
Phosphorylated Compounds ◽  
Pool Sizes

To identify the physiological and biochemical events leading to the negative effects of sucrose in culture medium on the photosynthetic capacity of plantlets cultivated in vitro, time-course changes in photosynthesis, metabolize pool sizes, and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity were investigated in strawberry (Fragaria × ananassa Duch. cv. Kent) plantlets following their transfer to medium with or without sucrose. When the plantlets grown in medium without sucrose were transferred to a similar medium with 30 g sucrose/liter, their net photosynthesis decreased and their level of phosphorylated compounds increased with time. In addition, initial Kcat, total Kcat, and the activation state of Rubisco decreased in these plantlets. Conversely, when the plantlets grown in medium with 30 g sucrose/liter were transferred to a similar medium without sucrose, their net photosynthesis slowly increased with time and their level of phosphorylated compounds slowly decreased. A slow increase with time of initial Kcat, total Kcat, and the activation state of Rubisco was also observed in these plantlets. The results of the present research suggest that the reduced photosynthetic capacity of strawberry plantlets cultivated in vitro in the presence of sucrose was the consequence of reduced Rubisco efficiency due to its deactivation and the possible presence of a putative tight binding inhibitor.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Design of a rubble mound breakwater under the combined effect of wave heights and water levels, under present and future climate conditions

2021 ◽  
Vol 112 ◽  
pp. 102711
Author(s):  
Soheil Radfar ◽  
Mehdi Shafieefar ◽  
Hassan Akbari ◽  
Panagiota A. Galiatsatou ◽  
Ahmad Rezaee Mazyak
Keyword(s):  
Water Levels ◽  
Future Climate ◽  
Combined Effect ◽  
Climate Conditions ◽  
Wave Heights ◽  
Rubble Mound

scholarly journals Exogenous melatonin improves the salt tolerance of cotton by removing active oxygen and protecting photosynthetic organs

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dan Jiang ◽  
Bin Lu ◽  
Liantao Liu ◽  
Wenjing Duan ◽  
Yanjun Meng ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Oxidative Damage ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Photochemical Quenching ◽  
Plant Tolerance ◽  
Signal Molecule ◽  
Ion Balance ◽  
Photosynthetic System

Abstract Background As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0–500 μM MT treatments with salt stress induced by treatment with 150 mM NaCl. Results Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). Conclusions Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.

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