scholarly journals Diurnal Changes in Dark Respiration of Rice Plant Grown under Natural Light Conditions.

1998 ◽  
Vol 67 (1) ◽  
pp. 91-93 ◽  
Author(s):  
Kuniyuki SAITOH ◽  
Mitsuru SUGIMOTO
Keyword(s):  
Rice Plant ◽  
Dark Respiration ◽  
Natural Light ◽  
Diurnal Changes ◽  
Light Conditions ◽  
Plant Grown

scholarly journals Preliminary investigation on the interaction between some physiological processes in donors and acceptors of assimilates

2015 ◽  
Vol 42 (1) ◽  
pp. 143-162 ◽  
Author(s):  
Z. Starck
Keyword(s):  
Photosynthetic Activity ◽  
Dark Respiration ◽  
Sugar Content ◽  
Preliminary Investigation ◽  
Extended Period ◽  
Natural Light ◽  
Light Conditions ◽  
Physiological Processes ◽  
Bean Plants ◽  
P Absorption

The interaction between physiological processes in donors and acceptors of <sup>14</sup>C-assimilates was studied in sunflower and bean plants with temporarily limited supply of assimilates (shading a few days and then replacing in natural light conditions (NL)). An extended period of shading (4-7 days) affected growth of plants and reduced photosynthetic activity, especially in sunflower. The proportion of <sup>14</sup>C-transported to roots decreased and that to the stern increased as an effect of preshading and did not significantly change in plants replaced in natural light conditions a few days before <sup>14</sup>CO<sub>2</sub>-exposure. In preshaded blades and roots the rate of dark respiration decreased, but soon improved after a few days of NL conditions following the shading period. Absorption of <sup>32</sup>P coincided with root respiration and sugar content in bean plant, in contrast to sunflower where <sup>32</sup>P-absorption, calculated per l g of root dry matter in preshaded plants exceeded that in control ones.

Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

The photosynthetic response of American chestnut seedlings to differing light conditions

2007 ◽  
Vol 37 (9) ◽  
pp. 1714-1722 ◽  
Author(s):  
Heather M. Joesting ◽  
Brian C. McCarthy ◽  
Kim J. Brown
Keyword(s):  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Nitrogen Concentration ◽  
American Chestnut ◽  
Control Treatment ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Light Conditions ◽  
Eastern Deciduous Forest

Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.

scholarly journals Fluctuating light experiments and semi-automated plant phenotyping enabled by self-built growth racks and simple upgrades to the IMAGING-PAM

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Dominik Schneider ◽  
Laura S. Lopez ◽  
Meng Li ◽  
Joseph D. Crawford ◽  
Helmut Kirchhoff ◽  
...  
Keyword(s):  
Data Analysis ◽  
Low Cost ◽  
Growth Conditions ◽  
Research Field ◽  
Constant Light ◽  
Plant Phenotyping ◽  
Natural Light ◽  
Light Conditions ◽  
Fluctuating Light ◽  
Science Labs

Abstract Background Over the last years, several plant science labs have started to employ fluctuating growth light conditions to simulate natural light regimes more closely. Many plant mutants reveal quantifiable effects under fluctuating light despite being indistinguishable from wild-type plants under standard constant light. Moreover, many subtle plant phenotypes become intensified and thus can be studied in more detail. This observation has caused a paradigm shift within the photosynthesis research community and an increasing number of scientists are interested in using fluctuating light growth conditions. However, high installation costs for commercial controllable LED setups as well as costly phenotyping equipment can make it hard for small academic groups to compete in this emerging field. Results We show a simple do-it-yourself approach to enable fluctuating light growth experiments. Our results using previously published fluctuating light sensitive mutants, stn7 and pgr5, confirm that our low-cost setup yields similar results as top-prized commercial growth regimes. Moreover, we show how we increased the throughput of our Walz IMAGING-PAM, also found in many other departments around the world. We have designed a Python and R-based open source toolkit that allows for semi-automated sample segmentation and data analysis thereby reducing the processing bottleneck of large experimental datasets. We provide detailed instructions on how to build and functionally test each setup. Conclusions With material costs well below USD$1000, it is possible to setup a fluctuating light rack including a constant light control shelf for comparison. This allows more scientists to perform experiments closer to natural light conditions and contribute to an emerging research field. A small addition to the IMAGING-PAM hardware not only increases sample throughput but also enables larger-scale plant phenotyping with automated data analysis.

scholarly journals Development of an automatic visual grading system for grafting seedlings

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668626 ◽  
Author(s):  
Subo Tian ◽  
Zifan Wang ◽  
Jifeng Yang ◽  
Zichen Huang ◽  
Ruili Wang ◽  
...  
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Grading System ◽  
Natural Light ◽  
Maximum Frequency ◽  
Light Conditions ◽  
Visual Grading ◽  
Key Technology ◽  
Background Light ◽  
Blue Background

In this study, a visual grading system of vegetable grafting machine was developed. The study described key technology of visual grading system of vegetable grafting machine. First, the contrasting experiment was conducted between acquired images under blue background light and natural light conditions, with the blue background light chosen as lighting source. The Visual C++ platform with open-source computer vision library (Open CV) was used for the image processing. Subsequently, maximum frequency of total number of 0-valued pixels was predicted and used to extract the measurements of scion and rootstock stem diameters. Finally, the developed integrated visual grading system was experimented with 100 scions and rootstock seedlings. The results showed that success rate of grading reached up to 98%. This shows that selection and grading of scion and rootstock could be fully automated with this developed visual grading system. Hence, this technology would be greatly helpful for improving the grading accuracy and efficiency.

Studies on reflexion of light from silvery surfaces of fishes, with special reference to the bleak, Alburnus alburnus

1965 ◽  
Vol 45 (3) ◽  
pp. 683-703 ◽  
Author(s):  
E. J. Denton ◽  
J. A. C. Nicol
Keyword(s):  
Special Reference ◽  
Aquatic Environment ◽  
The Body ◽  
Natural Light ◽  
Light Conditions ◽  
Trachurus Trachurus ◽  
Reflecting Surfaces ◽  
Bleak Alburnus Alburnus ◽  
Different Parts

The problem of how a fish can make itself invisible in the natural light-conditions in an aquatic environment is discussed with particular reference to the silvery surfaces of fish.In fish which we have examined, the silvery surfaces are of two types: (1) an argenteum which consists of long thin crystals of guanine whose reflecting surfaces are approximately parallel with the surface of the fish; (2) layers of guanine crystals lying either on the inner surfaces of the scales or in the subdermis—these crystals are not, in general, orientated with their reflecting surfaces parallel with the surfaces of the fish, and are much broader than those of the argenteum.Methods are described by which the orientation of the crystal planes with respect to the planes of the scales on which they lie can be determined.The orientation of the crystals of type 2 in different parts of the body is described for the horse mackerel, Trachurus trachurus (L.), and for the bleak, Alburnus alburnus (L.).For the bleak it is shown that although the planes of the crystals are often very much inclined with respect to the planes of the scales, the long axes of the crystals are always approximately parallel with the planes of scales. The inclination of the crystals, therefore, is away from the scales across their short axes.Measurements of the light transmitted by silvery scales of the bleak show that they reflect light strongly when this falls obliquely on the crystals which they contain and that they are most transparent to light which strikes the scales in a direction perpendicular to the reflecting planes of the crystals.

scholarly journals Fluctuating light experiments and semi-automated plant phenotyping enabled by self-built growth racks and simple upgrades to the IMAGING-PAM

2019 ◽  
Author(s):  
Dominik Schneider ◽  
Laura S. Lopez ◽  
Meng Li ◽  
Joseph D. Crawford ◽  
Helmut Kirchhoff ◽  
...  
Keyword(s):  
Data Analysis ◽  
Low Cost ◽  
Growth Conditions ◽  
Research Field ◽  
Constant Light ◽  
Plant Phenotyping ◽  
Natural Light ◽  
Light Conditions ◽  
Fluctuating Light ◽  
Science Labs

AbstractBackgroundOver the last years, several plant science labs have started to employ fluctuating growth light conditions to simulate natural light regimes more closely. Many plant mutants reveal quantifiable effects under fluctuating light despite being indistinguishable from wild-type plants under standard constant light. Moreover, many subtle plant phenotypes become intensified and thus can be studied in more detail. This observation has caused a paradigm shift within the photosynthesis research community and an increasing number of scientists are interested in using fluctuating light growth conditions. However, high installation costs for commercial controllable LED setups as well as costly phenotyping equipment can make it hard for small academic groups to compete in this emerging field.ResultsWe show a simple do-it-yourself approach to enable fluctuating light growth experiments. Our results using previously published fluctuating light sensitive mutants, stn7 and pgr5, confirm that our low-cost setup yields similar results as top-prized commercial growth regimes. Moreover, we show how we increased the throughput of our Walz IMAGING-PAM, also found in many other departments around the world. We have designed a Python and R-based open source toolkit that allows for semi-automated sample segmentation and data analysis thereby reducing the processing bottleneck of large experimental datasets. We provide detailed instructions on how to build and functionally test each setup.ConclusionsWith material costs well below USD$1000, it is possible to setup a fluctuating light rack including a constant light control shelf for comparison. This allows more scientists to perform experiments closer to natural light conditions and contribute to an emerging research field. A small addition to the IMAGING-PAM hardware not only increases sample throughput but also enables larger-scale plant phenotyping with automated data analysis.

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