CAM ‐physiology and carbon gain of the orchid Phalaenopsis in response to light intensity, light integral and CO 2

2020 ◽  
Author(s):  
Sander W. Hogewoning ◽  
Stefan A.J. Boogaart ◽  
Evelien Tongerlo ◽  
Govert Trouwborst
Keyword(s):  
Light Intensity ◽  
Carbon Gain ◽  
Light Integral

scholarly journals Morphological and Physiological Properties of Greenhouse-Grown Cucumber Seedlings as Influenced by Supplementary Light-Emitting Diodes with Same Daily Light Integral

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 361
Author(s):  
Zhengnan Yan ◽  
Long Wang ◽  
Yifei Wang ◽  
Yangyang Chu ◽  
Duo Lin ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Emitting Diodes ◽  
Root Surface Area ◽  
Light Emitting ◽  
Cucumber Seedlings ◽  
Daily Light Integral ◽  
Physiological Properties ◽  
Light Duration ◽  
Light Integral

Insufficient light in autumn–winter may prolong the production periods and reduce the quality of plug seedlings grown in greenhouses. Additionally, there is no optimal protocol for supplementary light strategies when providing the same amount of light for plug seedling production. This study was conducted to determine the influences of combinations of supplementary light intensity and light duration with the same daily light integral (DLI) on the morphological and physiological properties of cucumber seedlings (Cucumis sativus L. cv. Tianjiao No. 5) grown in a greenhouse. A supplementary light with the same DLI of 6.0 mol m−2 d−1 was applied with the light duration set to 6, 8, 10, or 12 h d−1 provided by light-emitting diodes (LEDs), and cucumber seedlings grown with sunlight only were set as the control. The results indicated that increasing DLI using supplementary light promoted the growth and development of cucumber seedlings over those grown without supplementary light; however, opposite trends were observed in the superoxide dismutase (SOD) and catalase (CAT) activities. Under equal DLI, increasing the supplementary light duration from 6 to 10 h d−1 increased the root surface area (66.8%), shoot dry weight (24.0%), seedling quality index (237.0%), root activity (60.0%), and stem firmness (27.2%) of the cucumber seedlings. The specific leaf area of the cucumber seedlings decreased quadratically with an increase in supplementary light duration, and an opposite trend was exhibited for the stem diameter of the cucumber seedlings. In summary, increased DLI or longer light duration combined with lower light intensity with equal DLI provided by supplementary light in insufficient sunlight seasons improved the quality of the cucumber seedlings through the modification of the root architecture and stem firmness, increasing the mechanical strength of the cucumber seedlings for transplanting.

scholarly journals Both Multi-Segment Light Intensity and Extended Photoperiod Lighting Strategies, with the Same Daily Light Integral, Promoted Lactuca sativa L. Growth and Photosynthesis

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 857 ◽  
Author(s):  
Hanping Mao ◽  
Teng Hang ◽  
Xiaodong Zhang ◽  
Na Lu
Keyword(s):  
Quantum Yield ◽  
Light Intensity ◽  
Plant Growth ◽  
Light Stress ◽  
Photochemical Quenching ◽  
Daily Light Integral ◽  
Weak Light ◽  
Research On Application ◽  
Non Photochemical Quenching ◽  
Light Integral

With the rise of plant factories around the world, more and more crops are cultivated under artificial light. Studies on effects of lighting strategies on plant growth, such as different light intensities, photoperiods, and their combinations, have been widely conducted. However, research on application of multi-segment light strategies and associated plant growth mechanisms is still relatively lacking. In the present study, two lighting strategies, multi-segment light intensity and extended photoperiod, were compared with a constant light intensity with a 12 h light/12 h dark cycle and the same daily light integral (DLI). Both lighting strategies promoted plant growth but acted via different mechanisms. The multi-segment light intensity lighting strategy promoted plant growth by decreasing non-photochemical quenching (NPQ) of the excited state of chlorophyll and increasing the quantum yield of PSII electron transport (PhiPSII), quantum yield of the carboxylation rate (PhiCO2), and photochemical quenching (qP), also taking advantage of the circadian rhythm. The extended photoperiod lighting strategy promoted plant growth by compensating for weak light stress and increasing light-use efficiency by increasing chlorophyll content under weak light conditions.

scholarly journals Elevated CO2 Enhances Dynamic Photosynthesis in Rice and Wheat

2021 ◽  
Vol 12 ◽  
Author(s):  
Huixing Kang ◽  
Ting Zhu ◽  
Yan Zhang ◽  
Xinran Ke ◽  
Wenjuan Sun ◽  
...  
Keyword(s):  
Light Intensity ◽  
Carbon Gain ◽  
Substrate Effect ◽  
Sudden Increase ◽  
Photosynthetic Induction ◽  
Crop Species ◽  
Relative Contribution ◽  
Dynamic Photosynthesis ◽  
Photosynthetic Carbon ◽  
Time Required

Crops developed under elevated carbon dioxide (eCO2) exhibit enhanced leaf photosynthesis under steady states. However, little is known about the effect of eCO2 on dynamic photosynthesis and the relative contribution of the short-term (substrate) and long-term (acclimation) effects of eCO2. We grew an Oryza sativa japonica cultivar and a Triticum aestivum cultivar under 400 μmol CO2 mol−1 air (ambient, A) and 600 μmol CO2 mol−1 air (elevated, E). Regardless of growth [CO2], the photosynthetic responses to the sudden increase and decrease in light intensity were characterized under 400 (a) or 600 μmol CO2 mol−1 air (e). The Aa1, Ae2, Ea3, and Ee4 treatments were employed to quantify the acclimation effect (Ae vs. Ee and Aa vs. Ea) and substrate effect (Aa vs. Ae and Ea vs. Ee). In comparison with the Aa treatment, both the steady-state photosynthetic rate (PN) and induction state (IS) were higher under the Ae and Ee treatments but lower under the Ea treatment in both species. However, IS reached at the 60 sec after the increase in light intensity, the time required for photosynthetic induction, and induction efficiency under Ae and Ee treatment did not differ significantly from those under Aa treatment. The substrate effect increased the accumulative carbon gain (ACG) during photosynthetic induction by 45.5% in rice and by 39.3% in wheat, whereas the acclimation effect decreased the ACG by 18.3% in rice but increased it by 7.5% in wheat. Thus, eCO2, either during growth or at measurement, enhances the dynamic photosynthetic carbon gain in both crop species. This indicates that photosynthetic carbon loss due to an induction limitation may be reduced in the future, under a high-CO2 world.

The effect of some environmental factors on the growth of young aspen trees (Populus tremuloides) in controlled environments

1971 ◽  
Vol 49 (8) ◽  
pp. 1443-1453 ◽  
Author(s):  
G. C. Bate ◽  
D. T. Canvin
Keyword(s):  
Light Intensity ◽  
Photosynthetic Rate ◽  
Populus Tremuloides ◽  
Dark Respiration ◽  
Continuous Light ◽  
Carbon Gain ◽  
Fluorescent Light ◽  
Controlled Environment ◽  
Rate Of Photosynthesis ◽  
Photosynthesis And Respiration

Several populations (each of 32 trees) of young aspen trees (Populus tremuloides Michx) were allowed to break from dormancy in controlled environment cabinets. The rate of photosynthesis and dark respiration and the rate of carbon gain (as difference between photosynthesis and respiration) of the population as affected by photoperiod duration, light intensity, and day/night temperatures was determined by measuring the CO2 exchange of the whole population using the controlled environment cabinet as the plant chamber.The rates of photosynthesis of the plants were similar during both 12- or 18-h photoperiods. The rates of respiration during the corresponding night periods were also similar. In continuous light the photosynthetic rate remained unchanged if growth (expansion of new leaves) was rapid. During periods of slower growth, the photosynthetic rate in continuous light was reduced. In spite of this reduction in the rate of photosynthesis, carbon gain was still greatest under continuous light.In the day/night temperature study, the largest gains in carbon per day by the aspen trees were obtained at day/night temperatures of 15/10 °C or 15/15 °C. Higher day or night temperatures resulted in decreased rates of carbon gain.Increased light intensity from fluorescent lamps resulted in increased rates of photosynthesis. Addition of incandescent light to the fluorescent light resulted, in almost all cases, in decreased rates of photosynthesis. This may, in part, be due to effects on leaf temperature.Photosynthesis of the populations was usually maximal at the beginning of the photoperiod and decreased steadily during the photoperiod. The rate of decrease was directly related to the rate of photosynthesis at the beginning of the photoperiod.Both photosynthesis and respiration were affected by temperature and light but no clear relationship existed between the rate of CO2 exchange during the photoperiod and that during the nyctoperiod following.

scholarly journals Responses of Aspen Leaves to Heatflecks: Both Damaging and Non-Damaging Rapid Temperature Excursions Reduce Photosynthesis

Plants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 145 ◽  
Author(s):  
Katja Hüve ◽  
Irina Bichele ◽  
Hedi Kaldmäe ◽  
Bahtijor Rasulov ◽  
Fernando Valladares ◽  
...  
Keyword(s):  
Light Intensity ◽  
Stomatal Closure ◽  
Heat Pulse ◽  
Leaf Temperature ◽  
Cellular Damage ◽  
Carbon Gain ◽  
Hybrid Aspen ◽  
Membrane Conductivity ◽  
European Aspen ◽  
Heat Pulses

During exposure to direct sunlight, leaf temperature increases rapidly and can reach values well above air temperature in temperate forest understories, especially when transpiration is limited due to drought stress, but the physiological effects of such high-temperature events are imperfectly understood. To gain insight into leaf temperature changes in the field and the effects of temperature variation on plant photosynthetic processes, we studied leaf temperature dynamics under field conditions in European aspen (Populus tremula L.) and under nursery conditions in hybrid aspen (P. tremula × P. tremuloides Michaux), and further investigated the heat response of photosynthetic activity in hybrid aspen leaves under laboratory conditions. To simulate the complex fluctuating temperature environment in the field, intact, attached leaves were subjected to short temperature increases (“heat pulses”) of varying duration over the temperature range of 30 °C–53 °C either under constant light intensity or by simultaneously raising the light intensity from 600 μmol m−2 s−1 to 1000 μmol m−2 s−1 during the heat pulse. On a warm summer day, leaf temperatures of up to 44 °C were measured in aspen leaves growing in the hemiboreal climate of Estonia. Laboratory experiments demonstrated that a moderate heat pulse of 2 min and up to 44 °C resulted in a reversible decrease of photosynthesis. The decrease in photosynthesis resulted from a combination of suppression of photosynthesis directly caused by the heat pulse and a further decrease, for a time period of 10–40 min after the heat pulse, caused by subsequent transient stomatal closure and delayed recovery of photosystem II (PSII) quantum yield. Longer and hotter heat pulses resulted in sustained inhibition of photosynthesis, primarily due to reduced PSII activity. However, cellular damage as indicated by increased membrane conductivity was not found below 50 °C. These data demonstrate that aspen is remarkably resistant to short-term heat pulses that are frequent under strongly fluctuating light regimes. Although the heat pulses did not result in cellular damage, heatflecks can significantly reduce the whole plant carbon gain in the field due to the delayed photosynthetic recovery after the heat pulse.

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

1988 ◽  
Vol 46 ◽  
pp. 300-301
Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl
Keyword(s):  
Fatty Acid ◽  
Light Intensity ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Anabaena Variabilis ◽  
Chloroplast Envelope ◽  
Major Constituent ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Effect Of Light

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

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