scholarly journals Effects of Blue Light Deficiency on Acclimation of Light Energy Partitioning in PSII and CO2 Assimilation Capacity to High Irradiance in Spinach Leaves

2008 ◽  
Vol 49 (4) ◽  
pp. 664-670 ◽  
Author(s):  
Ryo Matsuda ◽  
Keiko Ohashi-Kaneko ◽  
Kazuhiro Fujiwara ◽  
Kenji Kurata
Keyword(s):  
Blue Light ◽  
Co2 Assimilation ◽  
High Irradiance ◽  
Energy Partitioning ◽  
Light Energy ◽  
Assimilation Capacity ◽  
Light Deficiency ◽  
Spinach Leaves

Xanthophyll cycle, light energy dissipation and electron transport in transgenic tobacco with reduced carbon assimilation capacity

2000 ◽  
Vol 27 (4) ◽  
pp. 289 ◽  
Author(s):  
Sari A. Ruuska ◽  
Susanne von Caemmerer ◽  
Murray R. Badger ◽  
T. John Andrews ◽  
G. Dean Price ◽  
...  
Keyword(s):  
Electron Transport ◽  
Transgenic Tobacco ◽  
Xanthophyll Cycle ◽  
Co2 Assimilation ◽  
Light Energy ◽  
Pigment Composition ◽  
Wild Type ◽  
Xanthophyll Cycle Pigments ◽  
Leaf Pigment ◽  
Assimilation Capacity

The effects of reduced CO2 assimilation capacity on the leaf pigment composition and the dissipation of light energy were studied using transgenic tobacco (Nicotiana tabacum L. cv. W38). Two plant types were used: anti-SSu plants with reduced amounts of Rubisco and anti-GAPDH plants with reduced activity of chloroplast glycer-aldehyde 3-phosphate dehydrogenase. A moderate reduction in the photosynthetic capacity increased the de-epoxidation state of the xanthophyll-cycle pigments. In contrast, there was no large effect on the leaf pigment composition and the ratio of the xanthophyll cycle pigments to chlorophyll, and total carotenoids increased only in the most severe transgenic plants. The light induction of photosynthesis, fluorescence quenching and de-epoxida ion of the xanthophyll cycle pigments were also followed in wild-type and anti-SSu plants. Anti-SSu plants maintained high nonphotochemical quenching and increased xanthophyll de-epoxidation in the light but the reduction state of QA remained high. For both wild-type and anti-SSu plants, the electron transport rate estimated from chlorophyll a fluorescence appeared to be much higher than that required to support the observed rate of CO2 assimilation and photorespiration during the early phase of photosynthetic induction. However, the two estimates converged with the onset of steady-state photosynthesis.

AMELIORATION OF UV-B DAMAGE UNDER HIGH IRRADIANCE. II: ROLE OF BLUE LIGHT PHOTORECEPTORS

1994 ◽  
Vol 60 (2) ◽  
pp. 110-115 ◽  
Author(s):  
Paulien Adamse ◽  
Steven J. Britz ◽  
Charles R. Caldwell
Keyword(s):  
Blue Light ◽  
High Irradiance

scholarly journals Pupillary Responses to High-Irradiance Blue Light Correlate with Glaucoma Severity

Ophthalmology ◽  
2015 ◽  
Vol 122 (9) ◽  
pp. 1777-1785 ◽  
Author(s):  
Annadata V. Rukmini ◽  
Dan Milea ◽  
Mani Baskaran ◽  
Alicia C. How ◽  
Shamira A. Perera ◽  
...  
Keyword(s):  
Blue Light ◽  
High Irradiance ◽  
Pupillary Responses

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.

ENHANCEMENT OF LIGHT EXTRACTING FROM GaN-BASED BLUE LIGHT EMITTING DIODES USING PHOTONIC CRYSTAL

2012 ◽  
Vol 26 (12) ◽  
pp. 1250071 ◽  
Author(s):  
YAN WANG ◽  
FUGEN WU ◽  
XIN ZHANG ◽  
YUANWEI YAO ◽  
HUILIN ZHONG ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Blue Light ◽  
Light Emitting Diodes ◽  
Light Energy ◽  
Light Extraction ◽  
Light Emitting ◽  
Blue Led ◽  
Defect Area

Photonic crystal (PC) structures on LED have been known to enhance the light extraction significantly. In this paper, we report the light energy of GaN -based blue lighting emitting diode (LED) with perfect area photonic crystal (PPC) structure and defect area photonic crystal (DPC) structure. As a result, the light extracting energy of LEDs with PPC structure enhanced little compared to that of without PC structure. In addition, the light extracting energy of blue LED with DPC structure was remarkably improved.

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 Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO2 Assimilation Capacity of the Canopy Top with Changing Environment

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1278
Author(s):  
Satoshi Kitaoka ◽  
Qu Laiye ◽  
Yoko Watanabe ◽  
Makoto Watanabe ◽  
Toshihiro Watanabe ◽  
...  
Keyword(s):  
Seasonal Change ◽  
High Growth ◽  
Co2 Assimilation ◽  
High Growth Rate ◽  
Japanese Larch ◽  
Leaf Mass Per Area ◽  
Larix Kaempferi ◽  
Yearly Variation ◽  
The Difference ◽  
Assimilation Capacity

Japanese larch (Larix kaempferi = L. leptolepis) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (Psat) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in Psat in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.

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