Photosynthetic characteristics of a purple sulfur bacterium grown under different light intensities

1972 ◽  
Vol 18 (12) ◽  
pp. 1825-1828 ◽  
Author(s):  
M. Takahashi ◽  
K. Shiokawa ◽  
S. Ichimura
Keyword(s):  
Light Intensity ◽  
Photosynthetic Rate ◽  
Photosynthetic Characteristics ◽  
High Light ◽  
Bacteriochlorophyll A ◽  
Low Light ◽  
Purple Sulfur Bacterium ◽  
Light Intensities ◽  
Rate Of Photosynthesis ◽  
Structural Mechanisms

Photosynthetic characteristics of a purple sulfur bacterium, Chromatium, strain D, cultured under various light intensities were examined. With a decrease in the light intensity used for culture, the bacteriochlorophyll a content per unit cell nitrogen increased. Also, at low light intensities, the rate of photosynthesis (per unit bacteriochlorophyll a) was higher in samples grown under low light than in those grown under high light. These two responses to low light intensity are adaptations that ensure a high photosynthetic rate for the purple sulfur bacterium that usually occurs in a dimly lit environment. Possible chemical and structural mechanisms involved are discussed.

scholarly journals Light intensity regulates phototaxis, foraging and righting behaviors of the sea urchin Strongylocentrotus intermedius

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8001 ◽  
Author(s):  
Jiangnan Sun ◽  
Xiaomei Chi ◽  
Mingfang Yang ◽  
Jingyun Ding ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Foraging Behavior ◽  
Sea Urchins ◽  
High Light Intensity ◽  
High Light ◽  
Strongylocentrotus Intermedius ◽  
Low Light ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Significant Difference

Small sea urchins Strongylocentrotus intermedius (1–2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24–209 lx) and high light intensity (252–2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69–209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252–690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

scholarly journals Transcriptome analysis of genes and pathways associated with metabolism in Scylla paramamosain under different light intensities during indoor overwintering

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Li ◽  
Junming Zhou ◽  
Huan Wang ◽  
Changkao Mu ◽  
Ce Shi ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Light Intensity ◽  
Differentially Expressed Genes ◽  
High Light ◽  
Differentially Expressed ◽  
Scylla Paramamosain ◽  
Strong Impact ◽  
Low Light ◽  
Light Intensities ◽  
Light Group

Abstract Background Scylla paramamosain is one of the commercially crucial marine crustaceans belonging to the genus Scylla, which is commonly distributed along the coasts of China, Vietnam, and Japan. Genomic and transcriptomic data are scarce for the mud crab. Light intensity is one of the ecological factors that affect S. paramamosain during indoor overwintering. To understand the energy metabolism mechanism adapted to light intensity, we analyzed the transcriptome of S. paramamosain hepatopancreas in response to different light intensities (0, 1.43, 40.31 μmol·m− 2·s− 1). Results A total of 5052 differentially expressed genes were identified in low light group (LL group, 3104 genes were up-regulated and 1948 genes were down-regulated). A total of 7403 differentially expressed genes were identified in high light group (HL group, 5262 genes were up-regulated and 2141 genes were down-regulated). S. paramamosain adapts to different light intensity environments through the regulation of amino acids, fatty acids, carbon and energy metabolism. Different light intensities had a strong impact on the energy generation of S. paramamosain by influencing oxygen consumption rate, aerobic respiration, glycolysis/gluconeogenesis pathway, the citrate cycle (TCA cycle) and fatty acid degradation. Conclusion Low light is more conducive to the survival of S. paramamosain, which needs to produce and consume relatively less energy to sustain physiological activities. In contrast, S. paramamosain produced more energy to adapt to the pressure of high light intensities. The findings of the study add to the knowledge of regulatory mechanisms related to S. paramamosain metabolism under different light intensities.

Factors affecting growith and distribution of kauri (Agathis australis Salisb.) I. Effect of light on the establishment of Kaura and of Phyllocladus trichomanoides D.Don

1959 ◽  
Vol 7 (3) ◽  
pp. 252 ◽  
Author(s):  
RL Bieleski
Keyword(s):  
Light Intensity ◽  
Frequency Distribution ◽  
High Light Intensity ◽  
High Light ◽  
Low Light ◽  
Factors Affecting ◽  
Light Intensities ◽  
Seedling Distribution ◽  
Conifer Seedling ◽  
Effect Of Light

A method for determining the effect of light on seedling distribution in the field is described. It can be applied when seedling frequencies are as low as 1/m2. The frequency distribution of light intensities occupied by seedlings in a quadrat is compared with the frequency distribution of light intensities measured on a grid in the quadrat. This method was used to study the effect of light intensity on the establishment of two New Zealand gymnosperms, kauri (Agathis australis) and Phyllocladus trichomanoides, in the nursery community, a semimature Leptospermum scoparium – L. ericoides associes. Kauri and Phyllocladus did not occur at light intensities below 0.015 and 0.018 full daylight respectively. This limitation appeared to be due to the low light intensity presumably limiting photosynthesis. Kauri, but not Phyllocladus, also showed a high light intensity limit, at 0.30 full daylight, above which seedlings did not establish. Reasons are given for considering this as an indirect effect, probably through related solar heating affecting soil temperature or moisture. The optimal light intensity for kauri and Phyllocladus seedling establishment was close to the modal light intensity under the Leptospermum community: Leptospermum spp. were incapable of regenerating under their own cover. These two reasons appear to explain the suitability of the Leptospermum community as a nurse crop for the two conifer seedling species.

Selection for light preference during ovipositing in Drosophila pseudoobscura

1983 ◽  
Vol 25 (5) ◽  
pp. 446-449 ◽  
Author(s):  
Marvin B. Seiger ◽  
Amelia Broach Sanner
Keyword(s):  
Light Intensity ◽  
Genetic Variability ◽  
High Light Intensity ◽  
High Light ◽  
Drosophila Pseudoobscura ◽  
Low Light ◽  
Original Population ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Light Preference

Selection was carried out on a population of Drosophila pseudoobscura to obtain lines preferring high-light intensity or low-light intensity during oviposition. This species is generally characterized as preferring low-light intensities. It was possible to select for increased preference for high-light intensity, but not for low-light intensity during oviposition. However, additive genetic variability exists in preferences for both high- and low-light intensities. The original population was probably operating at a photonegative extreme for oviposition, yet maintained enough genetic variability to permit selection toward a photopositive preference.

scholarly journals Transcriptome analysis of genes and pathways associated with metabolism in Scylla paramamosain under different light intensities during indoor overwintering

2020 ◽  
Author(s):  
Na Li ◽  
Junming Zhou ◽  
Huan Wang ◽  
Changkao Mu ◽  
Ce Shi ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Light Intensity ◽  
Differentially Expressed Genes ◽  
High Light ◽  
Differentially Expressed ◽  
Scylla Paramamosain ◽  
Strong Impact ◽  
Low Light ◽  
Light Intensities ◽  
Light Group

Abstract Background: Scylla paramamosain is one of the commercially crucial marine crustaceans belonging to the genus Scylla , which is commonly distributed along the coasts of China, Vietnam, and Japan. Genomic and transcriptomic data are scarce for the mud crab. Light intensity is one of the ecological factors that affect S. paramamosain during indoor overwintering. To understand the energy metabolism mechanism adapted to light intensity, we analyzed the transcriptome of S. paramamosain hepatopancreas in response to different light intensities (0, 1.43, 40.31 μmol·m -2 ·s -1 ). Results: A total of 5052 differentially expressed genes were identified in low light group (LL group, 3104 genes were up-regulated and 1948 genes were down-regulated). A total of 7403 differentially expressed genes were identified in high light group (HL group, 5262 genes were up-regulated and 2141 genes were down-regulated). S. paramamosain adapts to different light intensity environments through the regulation of amino acids, fatty acids, carbon and energy metabolism. Different light intensities had a strong impact on the energy generation of S. paramamosain by influencing oxygen consumption rate, aerobic respiration, glycolysis/gluconeogenesis pathway, the citrate cycle (TCA cycle) and fatty acid degradation. Conclusion: Low light is more conducive to the survival of S. paramamosain , which needs to produce and consume relatively less energy to sustain physiological activities. In contrast, S. paramamosain produced more energy to adapt to the pressure of high light intensities. The findings of the study add to the knowledge of regulatory mechanisms related to S. paramamosain metabolism under different light intensities.

Inhibition of photosynthesis by low oxygen concentrations

1981 ◽  
Vol 59 (5) ◽  
pp. 721-725 ◽  
Author(s):  
P. B. E. McVetty ◽  
D. T. Canvin
Keyword(s):  
Oxygen Concentration ◽  
High Light ◽  
Low Oxygen ◽  
Low Light ◽  
Light Intensities ◽  
Oxidation Reduction ◽  
Transport Chain ◽  
Rate Of Photosynthesis ◽  
Effect Of Oxygen ◽  
Temporary Inhibition

The effect of changing the oxygen concentration from 21 to 2% on photosynthesis of wheat, sunflower, and soybean was investigated. At low CO2 concentrations and low light intensities, a stimulation of photosynthesis was observed in 2% oxygen compared with the rate in 21% O2. At high CO2 concentrations and high light intensities, a temporary inhibition of photosynthesis was observed when the oxygen concentration was changed from 21 to 2%. In wheat and sunflower, this inhibition was observed at progressively lower CO2 concentrations as temperatures were decreased. In soybean only, a slight inhibition of photosynthesis was observed at higher temperatures. In some cases, especially in plants grown under a low light intensity, a long-lasting (> 45 min) inhibition of photosynthesis was observed. In most cases, however, the inhibition lasted only for several minutes and final rates of photosynthesis in 2% O2 were equal to or greater than the rate of photosynthesis in 21% O2. The stimulatory effect of oxygen on photosynthesis at high CO2 concentrations and high light intensities could possibly be due to a regulation of the oxidation–reduction state of the electron transport chain and the maintenance of phosphorylation.

SAWFLY RESISTANCE IN WHEAT: IV. SOME EFFECTS OF LIGHT INTENSITY ON RESISTANCE

1961 ◽  
Vol 41 (3) ◽  
pp. 457-465 ◽  
Author(s):  
D. W. A. Roberts ◽  
C. Tyrrell
Keyword(s):  
Light Intensity ◽  
High Intensity ◽  
High Light ◽  
Low Light ◽  
Wheat Stem Sawfly ◽  
Low Resistance ◽  
Light Intensities ◽  
Stem Solidness ◽  
Maximum Expression ◽  
High Intensity Light

The degree of resistance to the wheat stem sawfly (Cephus cinctus Nort.) of seven varieties of wheat grown under shaded conditions was shown to be lower than that of plants grown under unshaded conditions. The breakdown of resistance of Rescue wheat grown in the greenhouse in the winter was prevented by a high-intensity light supplement of 4000 foot-candles but not by a supplement of 1500 foot-candles. The low resistance of Rescue wheat grown in the greenhouse results from low light intensities in the greenhouse in both summer and winter. It was concluded that high light intensities are required for the maximum expression of stem-solidness and sawfly resistance in Rescue wheat.

scholarly journals Light control of catechin accumulation is mediated by photosynthetic capacity in tea plant (Camellia sinensis)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ping Xiang ◽  
Qiufang Zhu ◽  
Marat Tukhvatshin ◽  
Bosi Cheng ◽  
Meng Tan ◽  
...  
Keyword(s):  
Light Intensity ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Photosynthetic Capacity ◽  
Epigallocatechin Gallate ◽  
Tea Plant ◽  
High Light ◽  
Light Intensities ◽  
Tea Plants

Abstract Background Catechins are crucial in determining the flavour and health benefits of tea, but it remains unclear that how the light intensity regulates catechins biosynthesis. Therefore, we cultivated tea plants in a phytotron to elucidate the response mechanism of catechins biosynthesis to light intensity changes. Results In the 250 μmol·m− 2·s− 1 treatment, the contents of epigallocatechin, epigallocatechin gallate and total catechins were increased by 98.94, 14.5 and 13.0% respectively, compared with those in the 550 μmol·m− 2·s− 1 treatment. Meanwhile, the photosynthetic capacity was enhanced in the 250 μmol·m− 2·s− 1 treatment, including the electron transport rate, net photosynthetic rate, transpiration rate and expression of related genes (such as CspsbA, CspsbB, CspsbC, CspsbD, CsPsbR and CsGLK1). In contrast, the extremely low or high light intensity decreased the catechins accumulation and photosynthetic capacity of the tea plants. The comprehensive analysis revealed that the response of catechins biosynthesis to the light intensity was mediated by the photosynthetic capacity of the tea plants. Appropriately high light upregulated the expression of genes related to photosynthetic capacity to improve the net photosynthetic rate (Pn), transpiration rate (Tr), and electron transfer rate (ETR), which enhanced the contents of substrates for non-esterified catechins biosynthesis (such as EGC). Meanwhile, these photosynthetic capacity-related genes and gallic acid (GA) biosynthesis-related genes (CsaroB, CsaroDE1, CsaroDE2 and CsaroDE3) co-regulated the response of GA accumulation to light intensity. Eventually, the epigallocatechin gallate content was enhanced by the increased contents of its precursors (EGC and GA) and the upregulation of the CsSCPL gene. Conclusions In this study, the catechin content and photosynthetic capacity of tea plants increased under appropriately high light intensities (250 μmol·m− 2·s− 1 and 350 μmol·m− 2·s− 1) but decreased under extremely low or high light intensities (150 μmol·m− 2·s− 1 or 550 μmol·m− 2·s− 1). We found that the control of catechin accumulation by light intensity in tea plants is mediated by the plant photosynthetic capacity. The research provided useful information for improving catechins content and its light-intensity regulation mechanism in tea plant.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

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