Photosynthetic rate of the marine diatom Cylindrotheca closterium

1967 ◽  
Vol 18 (2) ◽  
pp. 123 ◽  
Author(s):  
GF Humphrey ◽  
DV Subba Rao
Keyword(s):  
Blue Light ◽  
Photosynthetic Rate ◽  
White Light ◽  
Culture Medium ◽  
Spectral Composition ◽  
Compensation Point ◽  
Marine Diatom ◽  
Ph Change ◽  
Cylindrotheca Closterium

Photosynthesis in Cylindrotheca closterium was greatest in 1-day-old cells (2-4 � O2 per 106 cells per hour), declining to about 50% of this at 3 days and to about 10 % at 14 days. Due mainly to a decrease in the intensity of photosynthesis the ratio of photosynthesis to respiration fell from 6-8 at 1 day to 34 at 3 days, and to 0.6-1.6 at 14 days. The decline in photosynthesis started before phosphate or nitrate in the culture medium was exhausted, but was accompanied by a pH change from 7.4 before inoculation to 8.4 at 1 day and 9.2 at 3 days and thereafter. White light of 1000-1500f.c. (6.4-9.6 mW/cm2) saturated photosynthesis, the compensation point varying from 50 to 100 f.c. (0.3-0.6 mW/cm2). In blue light similar in spectral composition to that found at 10m below the surface of the ocean, the compensation point was 0.5-0.6 mW/cm2.

scholarly journals The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko
Keyword(s):  
Chlorophyll Content ◽  
Blue Light ◽  
White Light ◽  
Leaf Shape ◽  
Red Light ◽  
Spectral Composition ◽  
Fresh Weight ◽  
Light Spectrum ◽  
Dark Green ◽  
Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

scholarly journals Photosynthesis of the Cyanidioschyzon merolae cells in blue, red, and white light

2020 ◽  
Vol 147 (1) ◽  
pp. 61-73
Author(s):  
Eugeniusz Parys ◽  
Tomasz Krupnik ◽  
Ilona Kułak ◽  
Kinga Kania ◽  
Elżbieta Romanowska
Keyword(s):  
Blue Light ◽  
White Light ◽  
Red Light ◽  
Carbonic Anhydrase Activity ◽  
Compensation Point ◽  
Cyanidioschyzon Merolae ◽  
Rate Of Photosynthesis ◽  
White Control ◽  
Β Carotene

AbstractPhotosynthesis and respiration rates, pigment contents, CO2 compensation point, and carbonic anhydrase activity in Cyanidioschizon merolae cultivated in blue, red, and white light were measured. At the same light quality as during the growth, the photosynthesis of cells in blue light was significantly lowered, while under red light only slightly decreased as compared with white control. In white light, the quality of light during growth had no effect on the rate of photosynthesis at low O2 and high CO2 concentration, whereas their atmospheric level caused only slight decrease. Blue light reduced markedly photosynthesis rate of cells grown in white and red light, whereas the effect of red light was not so great. Only cells grown in the blue light showed increased respiration rate following the period of both the darkness and illumination. Cells grown in red light had the greatest amount of chlorophyll a, zeaxanthin, and β-carotene, while those in blue light had more phycocyanin. The dependence on O2 concentration of the CO2 compensation point and the rate of photosynthesis indicate that this alga possessed photorespiration. Differences in the rate of photosynthesis at different light qualities are discussed in relation to the content of pigments and transferred light energy together with the possible influence of related processes. Our data showed that blue and red light regulate photosynthesis in C. merolae for adjusting its metabolism to unfavorable for photosynthesis light conditions.

scholarly journals Effects of light qualities on growth, lipid contents and fatty acids profiles of Cylindrotheca closterium

2021 ◽  
Author(s):  
Congying Zhang Zhang ◽  
Ruibing Peng ◽  
Yi Wu ◽  
Zhihong Wu ◽  
Zuhao Zhang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Blue Light ◽  
White Light ◽  
Growth Rates ◽  
Light Quality ◽  
Green Light ◽  
Total Lipids ◽  
Yellow Light ◽  
Cylindrotheca Closterium ◽  
Lipid Contents

Abstract Background Marine diatoms were considered as a promising alternative to microbial resources for the development of biofuels, food additives, medicines and chemical materials. Light of wavelength is a principal element that can easily be controlled in microalgal scale-culture and influence the growth, pigment composition, and lipids accumulation of algal cells. With the increasing implementation of light-emitting diodes (LEDs) in microalgal production systems (photobioreactors), a measure of light quality controlled by LED could be suitable to improve microalgal yields. Results In this study, Cylindrotheca Closterium, a widely used diatom, influenced by five light quality (white, red, blue, green and yellow light) was tested for its effects of growth rates, chlorophylls contents, total lipids contents and fatty acids compositions. The growth and chlorophyll experiments also showed that the green and yellow light significantly improve the growth rates and chlorophylls contents than other groups (P < 0.05). The group white light showed the greatest increases in total lipid contents of C. closterium (P < 0.05). The group blue light had the highest polyunsaturated fatty acids (PUFAs) proportion (P < 0.05), while the group white showed the lowest PUFAs and the highest saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) proportions (P < 0.05). The proportions of SFAs and MUFAs were negatively correlated with growth, chlorophylls, and lipids. And the proportion of PUFAs and n-3 PUFA was positively correlated with growth chlorophylls, and lipids. Principal component analysis showed that the fatty acid composition differed among light quality groups. Conclusion In summary, green light and yellow light were conductive to boosting the growth and chlorophylls accumulation of C. closterium. White light increased total lipid yields, while blue light was superior in increasing the production of unsaturated fatty acids, especially on the timnodonic acid (EPA). The application of two-step methods to increase the production of biomass and fatty acids is an effective measure for the cultivation of C. closterium; green light is used to increase the growth, followed by white light cultivation to improve total lipids or blue light to enhance the proportion of PUFAs of C. closterium.

scholarly journals Effects of achromatic and chromatic lights on pupillary response, endocrinology, activity, and milk production in dairy cows

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253776
Author(s):  
Sofia Lindkvist ◽  
Emma Ternman ◽  
Sabine Ferneborg ◽  
Daniel Bånkestad ◽  
Johan Lindqvist ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Blue Light ◽  
Milk Production ◽  
Milk Yield ◽  
White Light ◽  
Pupil Size ◽  
Red Light ◽  
Spectral Composition ◽  
Management Tool ◽  
Lactating Cows

Artificial light can be used as a management tool to increase milk yield in dairy production. However, little is known about how cows respond to the spectral composition of light. The aim of this study was to investigate how dairy cows respond to artificial achromatic and chromatic lights. A tie-stall barn equipped with light-emitting diode (LED) light fixtures was used to create the controlled experimental light environments. Two experiments were conducted, both using dairy cows of Swedish Red and light mixtures with red, blue or white light. In experiment I, the response to light of increasing intensity on pupil size was evaluated in five pregnant non-lactating cows. In experiment II 16h of achromatic and chromatic daylight in combination with dim, achromatic night light, was tested on pregnant lactating cows during five weeks to observe long term effects on milk production, activity and circadian rhythms. Particular focus was given to possible carry over effects of blue light during the day on activity at night since this has been demonstrated in humans. Increasing intensity of white and blue light affected pupil size (P<0.001), but there was no effect on pupil size with increased intensity of red light. Milk yield was maintained throughout experiment II, and plasma melatonin was higher during dim night light than in daylight for all treatments (P<0.001). In conclusion, our results show that LED fixtures emitting red light driving the ipRGCs indirectly via ML-cones, blue light stimulating both S-cones and ipRGCs directly and a mixture of wavelengths (white light) exert similar effects on milk yield and activity in tied-up dairy cows. This suggests that the spectral composition of LED lighting in a barn is secondary to duration and intensity.

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

A novel green phosphor LaMgAl11O19:Ho3+ for near-UV/blue light-pumped white light-emitting diodes

2015 ◽  
Vol 618 ◽  
pp. 182-185 ◽  
Author(s):  
Xin Min ◽  
Minghao Fang ◽  
Zhaohui Huang ◽  
Hao Liu ◽  
Yan’gai Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Green Phosphor ◽  
Light Emitting ◽  
White Light Emitting Diodes

Blue-light imaging compared with high-definition white light for real-time histology prediction of colorectal polyps less than 1 centimeter: a prospective randomized study

2019 ◽  
Vol 89 (3) ◽  
pp. 554-564.e1 ◽  
Author(s):  
Emanuele Rondonotti ◽  
Silvia Paggi ◽  
Arnaldo Amato ◽  
Giuseppe Mogavero ◽  
Alida Andrealli ◽  
...  
Keyword(s):  
Real Time ◽  
Blue Light ◽  
White Light ◽  
Randomized Study ◽  
Colorectal Polyps ◽  
Prospective Randomized Study ◽  
High Definition
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