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 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 The Responses of Light Reaction of Photosynthesis to Dynamic Sunflecks in a Typically Shade-Tolerant Species Panax notoginseng

2021 ◽  
Vol 12 ◽  
Author(s):  
Jin-Yan Zhang ◽  
Qiang-Hao Zhang ◽  
Sheng-Pu Shuang ◽  
Zhu Cun ◽  
Hong-Min Wu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Heat Dissipation ◽  
Electron Flow ◽  
Panax Notoginseng ◽  
High Light ◽  
Low Light ◽  
Light Reaction ◽  
Tolerant Species ◽  
Shade Tolerant Species ◽  
Quantum Efficiency Of Psii

Light is highly heterogeneous in natural conditions, and plants need to evolve a series of strategies to acclimate the dynamic light since it is immobile. The present study aimed to elucidate the response of light reaction of photosynthesis to dynamic sunflecks in a shade-tolerant species Panax notoginseng and to examine the regulatory mechanisms involved in an adaptation to the simulated sunflecks. When P. notoginseng was exposed to the simulated sunflecks, non-photochemical quenching (NPQ) increased rapidly to the maximum value. Moreover, in response to the simulated sunflecks, there was a rapid increase in light-dependent heat dissipation quantum efficiency of photosystem II (PSII) (ΦNPQ), while the maximum quantum yield of PSII under light (Fv′/Fm′) declined. The relatively high fluorescence and constitutive heat dissipation quantum efficiency of PSII (Φf,d) in the plants exposed to transient high light (400, 800, and 1,600 μmol m–2 s–1) was accompanied by the low effective photochemical quantum yield of PSII (ΦPSII) after the dark recovery for 15 min, whereas the plants exposed to transient low light (50 μmol m–2 s–1) has been shown to lead to significant elevation in ΦPSII after darkness recovery. Furthermore, PSII fluorescence and constitutive heat dissipation electron transfer rate (Jf,d) was increased with the intensity of the simulated sunflecks, the residual absorbed energy used for the non-net carboxylative processes (JNC) was decreased when the response of electron transfer rate of NPQ pathway of PSII (JNPQ) to transient low light is restricted. In addition, the acceptor-side limitation of PSI [Y(NA)] was increased, while the donor-side limitation of photosystems I (PSI) [Y(ND)] was decreased at transient high light conditions accompanied with active cyclic electron flow (CEF). Meanwhile, when the leaves were exposed to transient high light, the xanthophyll cycle (V cycle) was activated and subsequently, the JNPQ began to increase. The de-epoxidation state [(Z + A)/(V + A + Z)] was strongly correlated with NPQ in response to the sunflecks. In the present study, a rapid engagement of lutein epoxide (Lx) after the low intensity of sunfleck together with the lower NPQ contributed to an elevation in the maximum photochemical quantum efficiency of PSII under the light. The analysis based on the correlation between the CEF and electron flow devoted to Ribulose-1, 5-bisphosphate (RuBP) oxygenation (JO) indicated that at a high light intensity of sunflecks, the electron flow largely devoted to RuBP oxygenation would contribute to the operation of the CEF. Overall, photorespiration plays an important role in regulating the CEF of the shade-tolerant species, such as P. notoginseng in response to transient high light, whereas active Lx cycle together with the decelerated NPQ may be an effective mechanism of elevating the maximum photochemical quantum efficiency of PSII under light exposure to transient low light.

scholarly journals Influence of High Temperature on Photosynthesis, Antioxidative Capacity of Chloroplast, and Carbon Assimilation among Heat-tolerant and Heat-susceptible Genotypes of Nonheading Chinese Cabbage

HortScience ◽  
2017 ◽  
Vol 52 (11) ◽  
pp. 1464-1470 ◽  
Author(s):  
Lingyun Yuan ◽  
Yujie Yuan ◽  
Shan Liu ◽  
Jie Wang ◽  
Shidong Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Chinese Cabbage ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Membrane Integrity ◽  
Photosynthetic Apparatus ◽  
Carbon Assimilation ◽  
Light Reaction ◽  
Chlorophyll Contents ◽  
Heat Tolerant

High temperature (HT) is a major environmental stress limiting oversummer production of nonheading Chinese cabbage (NHCC, Brassica campestris ssp. chinensis Makino). In the present study, the effects of HT on photosynthetic capacity, including light reaction and carbon assimilation, were completely investigated in two NHCC, ‘xd’ (heat-tolerant), and ‘sym’ (heat-susceptible). The two genotypes showed significant differences in plant morphology, photosynthetic capacity, and photosynthate metabolism (carboassimilation). HT caused a decrease in photosynthesis, chlorophyll contents, and photochemical activity in NHCC. However, these main photosynthetic-related parameters, including net photosynthetic rate (PN), maximal photochemical efficiency of PSII (Fv/Fm), and total chlorophyll content in ‘xd’, were significantly higher than those of ‘sym’ plants. The antioxidant contents and antioxidative enzyme activities of ascorbic acid-reduced glutathione cycle in the chloroplast of ‘xd’ were significantly higher than those of ‘sym’. Microscopic analyses revealed that HT affected the structure of photosynthetic apparatus and membrane integrity to a different extent, whereas ‘xd’ could maintain a better integrated chloroplast shape and thylakoid. Inhibited light reaction also hampered carbon assimilation, resulting in a decline of carboxylation efficiency and imbalance of carbohydrate metabolism. However, larger declined extents in these data were presented in ‘sym’ (heat-susceptible) than ‘xd’ (heat-tolerant). The heat-tolerant genotype ‘xd’ had a better capacity for self-protection by improved light reaction and carbon assimilation responding to HT stress.

Simultaneous Gas-Exchange and Fluorescence Measurements with Ozone-Fumigated Spruce

1994 ◽  
Vol 49 (11-12) ◽  
pp. 819-833
Author(s):  
Stefan Drenkard ◽  
Jürgen Maguhn ◽  
Dietmar Knoppik
Keyword(s):  
Gas Exchange ◽  
Calvin Cycle ◽  
Photosynthetic Apparatus ◽  
Early Summer ◽  
Assimilation Rate ◽  
Light Reaction ◽  
Fluorescence Measurements ◽  
Transport Chain ◽  
Short Time ◽  
Supply Information

A method was developed for carrying out gas-exchange and chlorophyll-fluorescence measurements simultaneously during fumigation of spruce twigs with peroxidic photooxidants. It is thus now possible to investigate how a pollutant affects distinct sectors of the photosynthetic apparatus of the plant: whereas fluorescence reveals any changes in the primary light reaction, CO2 gas-exchange measurements supply information about the biochemical reactions of the Calvin cycle. Results of short-time fumigation with 750 ppb ozone are presented here. Gas-exchange and fluorescence data are affected strongly in early summer, but not in autumn. The assimilation rate decreases significantly: primarily as a result of Rubisco activity and possibly because of direct inhibition of the electron-transport chain as well. Closure of the stomata leads to further reduction in the assimilation rate. Though no damage becomes visible on the needles, the perturbance of the photosynthetic apparatus caused by ozone fumigation is not reversible within 24 h.

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 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.

scholarly journals Photodamage to photosystem in a typically shade-tolerant species Panax notoginseng exposed to a sudden increase in light intensity

2021 ◽  
Vol 45 (4) ◽  
pp. 404-419
Author(s):  
Hong-Min WU ◽  
Sheng-Pu SHUANG ◽  
Jin-Yan ZHANG ◽  
Zhu CUN ◽  
Zhen-Gui MENG ◽  
...  
Keyword(s):  
Light Intensity ◽  
Panax Notoginseng ◽  
Sudden Increase ◽  
Tolerant Species ◽  
Shade Tolerant Species

scholarly journals Identification of Genes Required for Recycling Reducing Power during Photosynthetic Growth

2005 ◽  
Vol 187 (15) ◽  
pp. 5249-5258 ◽  
Author(s):  
Christine L. Tavano ◽  
Angela M. Podevels ◽  
Timothy J. Donohue
Keyword(s):  
Carbon Source ◽  
Calvin Cycle ◽  
Photosynthetic Apparatus ◽  
Reducing Power ◽  
Global Gene Expression ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Glycolate Metabolism ◽  
Global Gene Expression Analysis ◽  
Photoheterotrophic Growth

ABSTRACT Photosynthetic organisms have the unique ability to transform light energy into reducing power. We study the requirements for photosynthesis in the α-proteobacterium Rhodobacter sphaeroides. Global gene expression analysis found that ∼50 uncharacterized genes were regulated by changes in light intensity and O2 tension, similar to the expression of genes known to be required for photosynthetic growth of this bacterium. These uncharacterized genes included RSP4157 to -4159, which appeared to be cotranscribed and map to plasmid P004. A mutant containing a polar insertion in RSP4157, CT01, was able to grow via photosynthesis under autotrophic conditions using H2 as an electron donor and CO2 as a carbon source. However, CT01 was unable to grow photoheterotrophically in a succinate-based medium unless compounds that could be used to recycle reducing power (the external electron acceptor dimethyl sulfoxide (DMSO) or CO2) were provided. This suggests that the insertion in RSP4157 caused a defect in recycling reducing power during photosynthetic growth when a fixed carbon source was present. CT01 had decreased levels of RNA for genes encoding putative glycolate degradation functions. We found that exogenous glycolate also rescued photoheterotrophic growth of CT01, leading us to propose that CO2 produced from glycolate metabolism can be used by the Calvin cycle to recycle reducing power generated in the photosynthetic apparatus. The ability of glycolate, CO2, or DMSO to support photoheterotrophic growth of CT01 suggests that one or more products of RSP4157 to -4159 serve a previously unknown role in recycling reducing power under photosynthetic conditions.

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.

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