The xanthophyll cycle of Mantoniella squamata converts violaxanthin into antheraxanthin but not to zeaxanthin: consequences for the mechanism of enhanced non-photochemical energy dissipation

Planta ◽  
1998 ◽  
Vol 205 (4) ◽  
pp. 613-621 ◽  
Author(s):  
Reimund Goss ◽  
Karen Böhme ◽  
Christian Wilhelm
Keyword(s):  
Energy Dissipation ◽  
Xanthophyll Cycle ◽  
Mantoniella Squamata

Xanthophyll cycle, light energy dissipation and photosystem II down-regulation in senescent leaves of wheat plants grown in the field

2001 ◽  
Vol 28 (10) ◽  
pp. 1023 ◽  
Author(s):  
Congming Lu ◽  
Qingtao Lu ◽  
Jianhua Zhang ◽  
Qide Zhang ◽  
Tingyun Kuang
Keyword(s):  
Energy Dissipation ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Xanthophyll Cycle ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Down Regulation ◽  
Psii Efficiency ◽  
Psii Photochemistry ◽  
Assimilation Capacity

Photosynthesis, the xanthophyll cycle, light energy dissipation and down-regulation of photosystem II (PSII) in senescent leaves of wheat plants grown in the field were investigated. With the progress of senescence, maximal efficiency of PSII photochemistry decreased only slightly early in the morning but substantially at midday. Actual PSII efficiency, photochemical quenching, efficiency of excitation capture by open PSII centres, and the I–P phase of fluorescence induction curves decreased significantly and such decreases were much more evident at midday than in the morning. At the same time, non-photochemical quenching, thermal dissipation and de-epoxidation status of the xanthophyll cycle increased, with much greater increases at midday than in the morning. These results suggest that the xanthophyll cycle played a role in photoprotection of PSII in senescent leaves by dissipating excess excitation energy. Taking into account the substantial decrease in photosynthetic capacity in senescent leaves, our data seem to support the view that the decrease in actual PSII efficiency in senescent leaves may represent a mechanism to down-regulate photosynthetic electron transport to match the decreased CO2 assimilation capacity and avoid photodamage of PSII from excess excitation energy.

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.

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