Chlorophyll and Carotenoid Composition in Leaves of Euonymus kiautschovicus Acclimated to Different Degrees of Light Stress in the Field

1996 ◽  
Vol 23 (5) ◽  
pp. 649 ◽  
Author(s):  
B Demmig-Adams ◽  
WW Iii Adams
Keyword(s):  
Energy Dissipation ◽  
Xanthophyll Cycle ◽  
Light Stress ◽  
Single Species ◽  
Thermal Dissipation ◽  
Light Collection ◽  
Light Harvesting Complexes ◽  
Carotenoid Composition ◽  
Actual Degree ◽  
Β Carotene

The response of carotenoid and chlorophyll composition to the actual degree of excess light experienced in the natural environment was examined in differently angled leaves of the sclerophyllous shrub Euonymus kiautschovicus. Increasing light stress caused a greater conversion of the xanthophyll cycle to zeaxanthin and antheraxanthin as well as thermal dissipation of a greater fraction of the absorbed light. Increasing light stress was also associated with increasing chlorophyll alb ratios and increases in the pool size of the xanthophyll cycle. The response of all other carotenoids to light stress was less pronounced than that of the xanthophyll cycle pool. While the ratio of β-carotene or lutein to chlorophyll increased with increasing light stress, the ratio of neoxanthin to chlorophyll remained constant. Only the (taxonomically restricted) carotenoids lactucaxanthin and �-carotene decreased relative to chlorophyll with increasing light stress. These findings are consistent with an increased emphasis on energy dissipation over light collection with increasing light stress, afforded presumably by a decreased ratio of major, peripheral (bulk chlorophyll-binding) to minor, proximal (xanthophyll cycle-rich) light-harvesting complexes of photosystem II. These responses to light stress within a single species could not be extrapolated to comparisons among different groups of species.

Biochemical constrains limit the potential of the photochemical reflectance index as a predictor of effective quantum efficiency of photosynthesis during the winter spring transition in Jack pine seedlings

2009 ◽  
Vol 36 (11) ◽  
pp. 1016 ◽  
Author(s):  
Florian Busch ◽  
Norman P. A. Hüner ◽  
Ingo Ensminger
Keyword(s):  
Energy Dissipation ◽  
Quantum Efficiency ◽  
Xanthophyll Cycle ◽  
Physiological State ◽  
Jack Pine ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Invasive Technique ◽  
Photochemical Reflectance Index ◽  
Leaf Reflectance

Leaf reflectance spectral measurements are an emerging non-invasive technique that can be used to derive the photochemical reflectance index (PRI) to assess the physiological state of plants from leaf to ecosystem level. Changes in PRI are associated with changes in the xanthophyll cycle activity and provide an estimate of changes in the effective photochemical quantum efficiency (ΦII) during the growing season. However, we hypothesised that the correlation between PRI and ΦII might be poor when the xanthophyll cycle is primed for sustained thermal dissipation of the light energy absorbed. To test our hypothesis, we studied the recovery of winter acclimated Jack pine (Pinus banksiana Lamb.) seedlings that were exposed to different simulated spring recovery treatments in controlled environments. Different growth temperatures and light intensities were used to dissect the effect of these two factors on chlorophyll fluorescence, pigment composition and leaf reflectance. ΦII showed a clear response to temperature whereas PRI was mostly affected by light intensity. In contrast, the de-epoxidation state of the xanthophyll cycle pigments was both temperature and light dependent. Our data suggest that zeaxanthin-independent non-photochemical quenching is employed to various degrees in the different treatments. As a result, within the limits of our experimental setup, PRI could not explain the variation in ΦII. This indicates that an improved understanding of the different energy quenching mechanisms is critical to accurately interpret the PRI signal under environmental conditions where the predominant mode of excess energy dissipation does not involve a dynamic operation of the xanthophyll cycle, but a sustained mechanism of energy dissipation.

scholarly journals Photoprotective Mechanisms of `Concord' Grape Leaves in Relation to Iron Supply

2005 ◽  
Vol 130 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Brandon R. Smith ◽  
Lailiang Cheng
Keyword(s):  
Leaf Area ◽  
Antioxidant System ◽  
Xanthophyll Cycle ◽  
Thermal Dissipation ◽  
Fe Deficiency ◽  
Monodehydroascorbate Reductase ◽  
Fe Content ◽  
Area Basis ◽  
Antioxidant Metabolites ◽  
Β Carotene

The objective of this study was to quantify how photoprotective mechanisms in the leaves of `Concord' grapevines (Vitis labruscana Bailey) respond to a range of iron (Fe) supply. Own-rooted, 1-year-old container-grown vines were fertigated twice weekly for 11 weeks with a complete nutrient solution containing 1, 10, 20, 50, or 100 μm Fe from ferric ethylenediamine di (o-hydroxyphenylacetic) acid (Fe-EDDHA). Leaf total Fe content did not increase in response to Fe supply; however, “active” Fe (extracted with 2,2′-dipyridyl) and chlorophyll (Chl) increased on a leaf area basis as applied Fe increased. At the lowest active Fe level, leaf absorptance and the efficiency of excitation transfer (Fv′/Fm′) was lower, and nonphotochemical quenching (NPQ) was significantly greater. Photosystem II (PSII) quantum efficiency decreased curvilinearly, and the proportion of PSII reaction centers in the open state (qP) decreased linearly as active Fe content decreased. On a Chl basis, the xanthophyll cycle pool size [violaxanthin (V) + antheraxanthin (A) + zeaxanthin (Z)], lutein, and β-carotene increased curvilinearly as active Fe decreased, and neoxanthin (Neo) increased at the lowest Fe level. On a leaf area basis, as active Fe decreased, V+A+Z and β-carotene decreased curvilinearly, and lutein and Neo decreased linearly. At noon, conversion of V to A and Z increased as active Fe decreased. On a Chl basis, activities of antioxidant enzymes superoxide dismutase (SOD), monodehydroascorbate reductase (MDAR), and dehydroascorbate reductase (DHAR) increased curvilinearly, and glutathione reductase (GR) activity increased linearly as active Fe levels declined. Ascorbate peroxidase (APX) and catalase (CAT), on a Chl basis, were relatively constant. On a leaf area basis, a decrease in active Fe increased SOD and MDAR activity, whereas APX, CAT, DHAR and GR activity decreased. Antioxidant metabolites ascorbate (AsA), dehydroascorbate (DAsA), reduced glutathione (GSH) and oxidized glutathione (GSSG) also increased in response to Fe limitation when expressed on a Chl basis, whereas on a leaf area basis AsA and DAsA decreased and GSH increased curvilinearly. The GSH:GSSG ratio increased as active Fe declined, whereas the AsA:DAsA ratio did not change. In conclusion, both photoprotective mechanisms, xanthophyll cycle-dependent thermal dissipation and the ascorbate-glutathione antioxidant system, are enhanced in response to Fe deficiency to cope with excess absorbed light. In a low soil pH tolerant species such as V. labruscana, the foliar antioxidant system was upregulated in response to excess absorbed light from Fe deficiency-induced chlorosis, and there was no evidence of an increase in oxidative stress from high rates of applied Fe-EDDHA.

Diurnal and acclimatory responses of violaxanthin and lutein epoxide in the Australian mistletoe Amyema miquelii

2001 ◽  
Vol 28 (8) ◽  
pp. 793 ◽  
Author(s):  
Shizue Matsubara ◽  
Adam M. Gilmore ◽  
C. Barry Osmond
Keyword(s):  
Energy Dissipation ◽  
Chlorophyll A ◽  
Xanthophyll Cycle ◽  
Light Exposure ◽  
Higher Plant ◽  
Shade Acclimation ◽  
Chlorophylls A And B ◽  
Sun And Shade ◽  
Sun Leaves ◽  
Β Carotene

This study investigated the chloroplast pigment content of the Australian mistletoe Amyema miquelii (Lehm. ex Miq.) Tiegh. over diurnal periods in sun- and shade-acclimated leaves. Amyema miquelii exhibited the typical higher plant complement of neoxanthin, the xanthophyll cycle pigments, lutein, chlorophylls a and b and β carotene. Substantial levels of lutein epoxide were also present. Interestingly, diurnal light exposure elicited a decrease in lutein epoxide that paralleled the decrease in violaxanthin. Compared with shade-acclimated leaves, sun leaves exhibited reduced lutein epoxide and violaxanthin levels and higher chlorophyll a/b ratios. It is clear that the pools of violaxanthin and lutein epoxide respond in parallel to both diurnal light changes and sun–shade acclimation, although there seemed to be some differences in the recovery characteristics. These results raise a question as to whether lutein and lutein epoxide cycling may provide an auxiliary means of energy dissipation for some species.

Xanthophyll Cycle-Dependent Energy Dissipation and Flexible Photosystem II Efficiency in Plants Acclimated to Light Stress

1995 ◽  
Vol 22 (2) ◽  
pp. 249 ◽  
Author(s):  
B Demmig-Adams ◽  
WW Iii Adams ◽  
BA Logan ◽  
AS Verhoeven
Keyword(s):  
Energy Dissipation ◽  
Photosystem Ii ◽  
Xanthophyll Cycle ◽  
Light Stress ◽  
Photon Flux ◽  
Growth Environment ◽  
Psii Efficiency ◽  
Cycle Dependent ◽  
Shade Leaves ◽  
Sun Leaves

The effect of an acclimation to light stress during the growth of leaves on their response to high photon flux densities (PFDs) was characterised by quantifying changes in photosystem II (PSII) characteristics and carotenoid composition. During brief experimental exposures to high PFDs sun leaves exhibited: (a) much higher levels of antheraxanthin + zeaxanthin than shade leaves, (b) a greater extent of energy dissipation in the light-harvesting antennae, and (c) a greater decrease of intrinsic PSII efficiency that was rapidly reversible. During longer experimental exposures to high PFD, deep-shade leaves but not the sun leaves showed slowly developing secondary decreases in intrinsic PSII efficiency. Recovery of these secondary responses was also slow and inhibited by lincomycin, an inhibitor of chloroplast-encoded protein synthesis. In contrast, under field conditions all changes in intrinsic PSII efficiency in open sun-exposed habitats as well as understory sites with intense sunflecks appeared to be caused by xanthophyll cycle-dependent energy dissipation. Furthermore, comparison of leaves with different maximal rates of electron transport revealed that all leaves compensated fully for these differences by dissipating very different amounts of absorbed light via xanthophyll cycle-dependent energy dissipation, thereby all maintaining a similarly low PSII reduction state. It is our conclusion that an increased capacity for xanthophyll cycle-dependent energy dissipation is a key component of the acclimation of leaves to a variety of different forms of light stress, and that the response of leaves to excess light experienced in the growth environment is thus likely to be qualitatively different from that to sudden experimental exposures to PFDs exceeding the growth PFD.

scholarly journals Carotenoids from Cyanobacteria: Biotechnological Potential and Optimization Strategies

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 735
Author(s):  
Fernando Pagels ◽  
Vitor Vasconcelos ◽  
Ana Catarina Guedes
Keyword(s):  
Energy Dissipation ◽  
Industrial Production ◽  
Protein Complex ◽  
Biosynthetic Pathway ◽  
Environmentally Friendly ◽  
Potential Candidate ◽  
Biotechnological Potential ◽  
Photosynthetic Organisms ◽  
Orange Carotenoid Protein ◽  
Β Carotene

Carotenoids are tetraterpenoids molecules present in all photosynthetic organisms, responsible for better light-harvesting and energy dissipation in photosynthesis. In cyanobacteria, the biosynthetic pathway of carotenoids is well described, and apart from the more common compounds (e.g., β-carotene, zeaxanthin, and echinenone), specific carotenoids can also be found, such as myxoxanthophyll. Moreover, cyanobacteria have a protein complex called orange carotenoid protein (OCP) as a mechanism of photoprotection. Although cyanobacteria are not the organism of choice for the industrial production of carotenoids, the optimisation of their production and the evaluation of their bioactive capacity demonstrate that these organisms may indeed be a potential candidate for future pigment production in a more environmentally friendly and sustainable approach of biorefinery. Carotenoids-rich extracts are described as antioxidant, anti-inflammatory, and anti-tumoral agents and are proposed for feed and cosmetical industries. Thus, several strategies for the optimisation of a cyanobacteria-based bioprocess for the obtention of pigments were described. This review aims to give an overview of carotenoids from cyanobacteria not only in terms of their chemistry but also in terms of their biotechnological applicability and the advances and the challenges in the production of such compounds.

scholarly journals Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

2008 ◽  
Vol 55 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Jerzy Kruk ◽  
Renata Szymańska
Keyword(s):  
Substrate Specificity ◽  
Xanthophyll Cycle ◽  
Higher Plants ◽  
Light Stress ◽  
High Light ◽  
Light Conditions ◽  
Strong Light ◽  
Zeaxanthin Epoxidase ◽  
Typical Response ◽  
Cuscuta Species

In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

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