Independence of phytochrome destruction and physiological response in Avena and Pisum segment elongation

1972 ◽  
Vol 50 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. G. Hopkins
Keyword(s):  
Total Energy ◽  
Physiological Response ◽  
Maximum Rate ◽  
Red Light ◽  
Light Treatment ◽  
Low Energy ◽  
Maximum Efficiency ◽  
Avena Coleoptile ◽  
Physiological Action

Control over elongation in Avena coleoptile and Pisum epicotyl segments by cyclic far-red light treatment is dependent on the timing of successive irradiations and independent of total energy. The effect of each far-red irradiation in a cycle is cumulative. Maximum efficiency of far-red light in a cycle is obtained when the light treatments follow within 2 to 3 h of each other. Additional increments of elongation may also be obtained by successive red light treatment only when presented at least 8 to 9 h apart. The effect of a single far-red treatment is to establish a maximum rate of elongation which is maintained for no more than 3 h. The results offer support for the hypothesis that low-energy phytochrome mediated responses result from maintenance of low but maximally effective levels of Pfr and that Pfr destruction is essentially independent of physiological action.

Influence de la qualité de l'éclairement sur les corrélations entre le cotylédon et son bourgeon axillaire chez le Linum usitatissimum

1992 ◽  
Vol 70 (5) ◽  
pp. 1087-1092
Author(s):  
Ahmed Fathi Oueida ◽  
Marie-Odile Desbiez
Keyword(s):  
Key Words ◽  
Nutrient Solution ◽  
Linum Usitatissimum ◽  
Dark Period ◽  
Red Light ◽  
Light Treatment ◽  
Low Energy ◽  
Experimental Conditions

The precedence of one cotyledonary bud over another, as a result of the removal of one of the cotyledons, can be measured quantitatively using the precedence index, g. When g tends towards +1, it is the bud opposite to the deleted cotyledon that takes the precedence, whereas when it tends toward −1, it is the axillant one. When g is close to 0, it corresponds to a globally symmetrical population of plants, in which the bud opposite to the deleted cotyledon and the axillant bud take the precedence in an approximately equal number of plants. When the flax is taken, after decapitation and removal of one cotyledon, on deficient nutrient solution under photoperiodicity of 9 h light: 15 h dark, index g is not affected if the dark period is replaced totally by a low-energy (3 W∙m−2) red light or partly by four periods of 20 min of red light during the dark period. In contrast, blue or far red light, under the same experimental conditions, caused g to tend towards 0 for all cultivars. This effect of the blue or far red light was antagonized by a following red light treatment, which suggests the interference of phytochrome. These observations were not observed with a Knop, ion-rich nutrient solution and at 18 W∙m−2, where g index remained close to +1. Key words: Linum usitatissimum, photomorphogenesis, bud, cotyledon, correlation.

scholarly journals Single Wavelengths of LED Light Supplement Promote the Biosynthesis of Major Cyclic Monoterpenes in Japanese Mint

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1420
Author(s):  
Takahiro Ueda ◽  
Miki Murata ◽  
Ken Yokawa
Keyword(s):  
Blue Light ◽  
Solid Phase ◽  
Glandular Trichomes ◽  
Red Light ◽  
Glandular Trichome ◽  
Pulse Amplitude ◽  
Light Treatment ◽  
Led Light ◽  
Trichome Formation ◽  
Japanese Mint

Environmental light conditions influence the biosynthesis of monoterpenes in the mint plant. Cyclic terpenes, such as menthol, menthone, pulegone, and menthofuran, are major odor components synthesized in mint leaves. However, it is unclear how light for cultivation affects the contents of these compounds. Artificial lighting using light-emitting diodes (LEDs) for plant cultivation has the advantage of preferential wavelength control. Here, we monitored monoterpene contents in hydroponically cultivated Japanese mint leaves under blue, red, or far-red wavelengths of LED light supplements. Volatile cyclic monoterpenes, pulegone, menthone, menthol, and menthofuran were quantified using the head-space solid phase microextraction method. As a result, all light wavelengths promoted the biosynthesis of the compounds. Remarkably, two weeks of blue-light supplement increased all compounds: pulegone (362% increase compared to the control), menthofuran (285%), menthone (223%), and menthol (389%). Red light slightly promoted pulegone (256%), menthofuran (178%), and menthol (197%). Interestingly, the accumulation of menthone (229%) or menthofuran (339%) was observed with far-red light treatment. The quantification of glandular trichomes density revealed that no increase under light supplement was confirmed. Blue light treatment even suppressed the glandular trichome formation. No promotion of photosynthesis was observed by pulse-amplitude-modulation (PAM) fluorometry. The present result indicates that light supplements directly promoted the biosynthetic pathways of cyclic monoterpenes.

737 Prediction of drop out in an adjunctive light treatment trial in patients with non-seasonal depression and evening chronotype

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A287-A288
Author(s):  
Joey W Chan ◽  
Y K Wing ◽  
S P Lam ◽  
Shirley Xin Li ◽  
J Zhang
Keyword(s):  
Clinical Characteristics ◽  
Red Light ◽  
Bright Light ◽  
Fold Increase ◽  
Light Therapy ◽  
Light Treatment ◽  
Drop Out ◽  
Sleep Diary ◽  
Significant Difference ◽  
Seasonal Depression

Abstract Introduction Drop out during treatment hampers therapeutic effect of interventions. The current study examines the possible predictors of drop out during the five-week light treatment in patients with unipolar non-seasonal depression and evening-chronotype. Methods Baseline characteristics including demographics, sleep diary parameters, light treatment prescribed, and early clinical outcomes changes were compared between the Drop out and Non drop out group. Logistic regression analysis was used to examine predictors for drop out. All data were analyzed in a modified intention to treat analysis with last observation carried forward approach. Results A total of 91 subjects (Female 79%, 46.3 ± 11.8 years old) were included in the analysis. There was no significant difference in the baseline demographic and clinical characteristics between the Drop out and Non drop out group. There was also no significant difference in the improvement of clinical parameters over the first week among the two groups. However, treatment non-adherence (in terms of compliance of less than 80% of prescribed duration) over the first treatment week predicts a five-fold increase in risk of drop out during light therapy. (OR: 5.85, CI: 1.414–24.205, p=0.015) after controlling for potential confounders including age, gender, treatment group, patient expectation, and treatment-emergent adverse events. Conclusion This study found that baseline clinical characteristics including depression severity and improvement of depressive symptoms in the initial week did not differ between the Drop out and Non drop out group. The drop out was also not affected by the type of light (dim red versus bright red light), indirectly supporting dim red light as a valid placebo in bright light therapy trial. Treatment adherence is the early phase of light treatment is an important predictor of drop out. Support (if any):

Is the in vivo Photosystem I Function Resistant to Photoinhibition? An Answer from Photoacoustic and Far-Red Absorbance Measurements in Intact Leaves

1991 ◽  
Vol 46 (11-12) ◽  
pp. 1038-1044 ◽  
Author(s):  
Michel Havaux ◽  
Murielle Eyletters
Keyword(s):  
Light Stress ◽  
Red Light ◽  
Light Treatment ◽  
High Light ◽  
Saturation Curve ◽  
Strong Light ◽  
Ps Ii ◽  
Fluorescence Measurements ◽  
Ps I

Abstract Preillumination of intact pea leaves with a strong blue-green light of 400 W m-2 markedly inhibited both photoacoustically monitored O2-evolution activity and PS II photochemistry as estimated from chlorophyll fluorescence measurements. The aim of the present work was to examine, with the help of the photoacoustic technique, whether this high-light treatment deteriorated the in vivo PS I function too. High-frequency photoacoustic measurements indicated that photochemical conversion of far-red light energy in PS I was preserved (and even transiently stimulated) whereas photochemical energy storage monitored in light exciting both PS I and PS II was markedly diminished. Low-frequency photoacoustic measurements of the Emerson enhancement showed a spectacular change in the PS II/PS I activity balance in favor of PS I. It was also observed that the linear portion of the saturation curve of the far-red light effect in the Emerson enhancement was not changed by the light treatment. Those results lead to the conclusion that, in contrast to PS II, the in vivo PS I photofunctioning was resistant to strong light stress, thus confirming previous suggestions derived from in vitro studies. Estimation of the redox state of the PS I reaction center by leaf absorbance measurements at ca. 820 nm suggested that, under steady illumination, a considerably larger fraction of PS I centers were in the closed state in high-light pretreated leaves as compared to control leaves, presumably allowing passive adjustment of the macroscopic quantum yield of PS I photochemis­ try to the strongly reduced photochemical efficiency of photoinhibited PS II.

Die Wirkung von Phytochrom auf die Bildung von Einzelcarotinoiden in etiolierten Horde um -Keimlingen / The Influence of Phytochrome on the Formation of Individual Carotenoids in Etiolated Hordeum Seedlings

1975 ◽  
Vol 30 (1-2) ◽  
pp. 67-68 ◽  
Author(s):  
Hans K. Kleudgen ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
White Light ◽  
Accumulation Rate ◽  
Red Light ◽  
Light Treatment ◽  
Light Effects ◽  
Short Time ◽  
Β Carotene

Abstract Short time red pulses, given 6 times for 5 min within 36 h, induce in etiolated barley seedlings an enhanced synthesis of the main chloroplast carotenoids β-carotene, violaxanthine, lutein and neoxanthine. The level of antheraxanthine and zeaxanthine decreases by red light treatment. These red light effects are reverted by subsequent short time far-red pulses. The results show that the white light induced change in the accumulation rate of individual carotenoids is initiated and regulated by active phytochrome Pfr . In the case of neoxanthin and zeaxanthin the red light effects cannot be fully reverted by far-red; this points to very fast phytochrome reaction.

scholarly journals A study of the protein requirements of the mature breeding ewe

1967 ◽  
Vol 21 (4) ◽  
pp. 879-891 ◽  
Author(s):  
J. J. Robinson ◽  
T. J. Forbes
Keyword(s):  
Energy Intake ◽  
Crude Protein ◽  
Dry Matter ◽  
Daily Intake ◽  
High Energy ◽  
Low Energy ◽  
N Balance ◽  
Maximum Efficiency ◽  
Apparent Digestibility ◽  
N Retention

1. An experiment was carried out in which protein utilization in the pregnant ewe was studied using the nitrogen balance technique.2. Eight diets supplying four different intakes of crude protein and two different intakes of energy were each offered to eight individually penned ewes.3. The mean crude protein intakes per day were 7·2, 5·5, 4·1 and 3·0 g/kg W0·73 (where W = body-weight) and the metabolizable energy intakes 134 and 113 kcal/kg W0·73.4. N balances were carried out at 10–12, 14–16 and 18–20 weeks of gestation on five ewes from each treatment.5. The apparent digestibility of both dry matter and crude protein decreased with decreasing protein intake. With the high energy intake, the apparent dry-matter digestibility was increased and the apparent digestibility of crude protein decreased. Stage of gestation had no significant effect on the apparent digestibility of either of these constituents.6. N retention was not affected by the number of foetuses carried. With the higher energy intake and the higher protein intakes, the absolute retention of N was significantly increased at all stages of gestation. N retention increased with advancing pregnancy; the retentions at 10–12, 14–16 and 18–20 weeks of gestation being 0·086, 0·114 and 0·163 g/kg W0·73 per day respectively.7. The efficiency of utilization of apparently digested N was calculated from the regression of retained N as a percentage of apparently digested N against apparently digested N.8. The daily intakes of apparently digested N required for maximum efficiency were 0·551 and 0·620 g/kg W0·73 on the high and low energy intakes respectively. The daily intake for maximum efficiency decreased with advancing pregnancy, the values being 0·623, 0·587 and 0·567 g/kg W0·73 for the 10–12, 14–16 and 18–20 weeks of gestation respectively.9. The levels of N retained at maximum efficiency were 0·235 and 0·202 g/kg W0·73 per day for the high and low energy intakes respectively. The levels of N retained increased during pregnancy from 0·170 g/kg W0·73 per day at 10–12 weeks to 0·286 g/kg W0·73 at 18–20 weeks. The requirements for zero N balance were 0·072 and 0·153 g apparently digested N/kg W0·73 per day for the high and low energy intakes respectively. The requirement for zero N balance decreased from 0·176 g/kg W0·73 per day at 10–12 weeks to 0·071 g/kg W0·73 at 18–20 weeks.10. The results are discussed in relation to other research findings and current recommendations.

scholarly journals Triplet–triplet annihilation upconversion followed by FRET for the red light activation of a photodissociative ruthenium complex in liposomes

2015 ◽  
Vol 17 (41) ◽  
pp. 27380-27390 ◽  
Author(s):  
Sven H. C. Askes ◽  
Miroslav Kloz ◽  
Gilles Bruylants ◽  
John T. M. Kennis ◽  
Sylvestre Bonnet
Keyword(s):  
Lipid Bilayer ◽  
Ruthenium Complex ◽  
Red Light ◽  
High Energy ◽  
Low Energy ◽  
Light Activation ◽  
Triplet Triplet Annihilation

Three molecules in a single lipid bilayer to trigger high-energy photochemistry with low-energy photons.

scholarly journals THE RED LIGHT TREATMENT OF SMALL-POX: A REPLY.

The Lancet ◽  
1904 ◽  
Vol 164 (4236) ◽  
pp. 1272 ◽  
Author(s):  
NielsR. Finsen
Keyword(s):  
Red Light ◽  
Light Treatment ◽  
Small Pox

scholarly journals Trifluoroethoxy-Coated Subphthalocyanine affects Trifluoromethylation of Alkenes and Alkynes even under Low-Energy Red-Light Irradiation

ChemistryOpen ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 226-230 ◽  
Author(s):  
Kohei Matsuzaki ◽  
Tomoya Hiromura ◽  
Etsuko Tokunaga ◽  
Norio Shibata
Keyword(s):  
Red Light ◽  
Low Energy ◽  
Light Irradiation
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