Photosynthetic apparatus in Selaginella. I. Morphology and photosynthesis under different light and temperature regimes

1970 ◽  
Vol 48 (10) ◽  
pp. 1843-1852 ◽  
Author(s):  
Richard Jagels
Keyword(s):  
Light Intensity ◽  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Photosynthetic Rates ◽  
Sterile Culture ◽  
Light Levels ◽  
Light Intensities ◽  
Temperature Regimes ◽  
Normal Green ◽  
Branching Patterns

Several hydrophytic and umbrophilic species of Selaginella were grown in sterile culture and scrutinized for morphological and photosynthetic variability under light intensities between 0 and 500 ft-c and temperatures of 9° and 22 °C. Bleaching was induced by raising light intensity; and for a particular light intensity was enhanced by lowering temperature. Regreening could be achieved by reversing conditions. Branching patterns, leaf symmetry, and orientation of leaves to axis were also light dependent. Light levels which produced normal green plants for S. uncinata initiated only half-saturation photosynthetic rates. Photosaturating light intensities, if applied for several weeks, induced bleaching. Based on fresh or dry weight bleaching plants had lower photosynthetic rates than green plant's; but based on chlorophyll content the photosynthetic rates of green and bleaching plants were the same.

scholarly journals The Effect of Low Light Intensity and Temperature on Growth of Schefflera arboricola in Interior Landscapes

HortScience ◽  
2007 ◽  
Vol 42 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Astrid Kubatsch ◽  
Heiner Grüneberg ◽  
Christian Ulrichs
Keyword(s):  
Light Intensity ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Leaf Thickness ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Low Light ◽  
Light Intensities ◽  
Temperature Regimes ◽  
Schefflera Arboricola

Schefflera arboricola was held in light- and temperature-controlled chambers for 6 months under three light intensities of 10 μmol·m–2·s–1, 20 μmol·m–2·s–1, and 80 μmol·m–2·s–1 measured as photon flux density (PFD). Plants also received three temperature regimes: 15 °C, 20 °C, and 25 °C. Reduced light intensity significantly decreased fresh and dry weight and increased chlorophyll content, but did not affect leaf thickness and palisade and spongy mesophyll parenchyma. High temperatures reduced fresh weight and significantly increased chlorophyll content and leaf thickness. The authors conclude that reduced photosynthetic energy flow at low light intensities (10 μmol·m–2·s–1, 20 μmol·m–2·s–1) could not be buffered by a downregulation of energy-consuming processes. Therefore the life span and quality of S. arboricola is reduced at such PFD values, especially at higher temperatures. Plants lose their marketability within 6 months.

scholarly journals Leaf Characteristics and Yield Performance of Mungbean (Vigna radiata L.) Varieties under Different Levels of Shading

2018 ◽  
Vol 15 (2) ◽  
pp. 40-51
Author(s):  
M A Hossain ◽  
M A Hasan ◽  
S Sikder ◽  
A K M M B Chowdhury
Keyword(s):  
Light Intensity ◽  
Grain Yield ◽  
Vigna Radiata ◽  
Dry Weight ◽  
Light Levels ◽  
Spongy Layer ◽  
Partial Shade ◽  
Shade Condition ◽  
Reduced Light ◽  
Leaf Dry Weight

An experiment was carried out to evaluate the leaf characteristics and yield performances of mungbean (Vigna radiata L.) under different light levels at the Crop Physiology and Ecology Research Field of Hajee Mohammad Danesh Science and Technology University, Dinajpur during March to June 2016. The experiment was laid out in a split plot design with three replications. Three light levels (L100 - 100 % light intensity, L75- 75 % light intensity and L50- 50% light intensity) were assigned in the main plots and four varieties (BARl Mung-6, BINA Mung-8, BINA Mung-5 and BU Mug-4) were assigned in subplots. Mosquito nets of different pore size were used for maintaining 75 and 50 percent light intensity. Leaf area was increased due to reduced light levels in all mugbean varieties but the increment was significant in BINA Mung-5 and BINA Mung-8 only at 75% light intensity at 40 days after sowing and only in BARI Mung-6 with L50 and BU Mug-4 with L75 and L50at 50 days after sowing. Due to reduced light levels, leaf dry weight was affected more in BINA Mung-5 and BU Mug- 4 than BARI Mung-6 and BINA Mung-8. Leaf thickness was reduced under shade in all the mungbean varieties, except in BU Mug-4 at 75% light intensity, and the reduction in leaf thickness was mainly due to the reduction in thickness of spongy layer. The palisade layer thickness was influenced insignificantly but spongy layer thickness was increased in BINA Mung-5 at 100% light intensity. The grain yields (t ha-1) of BARI Mung-6 and BINA Mung-8 remained stable under partial shade condition but the grain yield of BINA Mung-5 and BU Mug-4 was reduced drastically under partial shade condition. Higher leaf dry weight, number of pods plant-1, seeds pod-1, and heavier grains in BARI Mung-6 and BINA Mung-8 contributed to the higher grain yield plant-1 under partial shade condition than in BINA Mung-5 and BU Mug-4.The Agriculturists 2017; 15(2) 40-51

scholarly journals Light Exposure during Days with Night, Outdoor, and Indoor Work

2019 ◽  
Vol 63 (6) ◽  
pp. 651-665 ◽  
Author(s):  
Stine Daugaard ◽  
Jakob Markvart ◽  
Jens Peter Bonde ◽  
Jens Christoffersen ◽  
Anne Helene Garde ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Exposure ◽  
Spectral Composition ◽  
Working Hours ◽  
Well Being ◽  
Outdoor Workers ◽  
Light Levels ◽  
Light Intensities ◽  
Treatment Of Depression ◽  
Night Shifts

Abstract Objective To assess light exposure during days with indoor, outdoor, and night work and days off work. Methods Light intensity was continuously recorded for 7 days across the year among indoor (n = 170), outdoor (n = 151), and night workers (n = 188) in Denmark (55–56°N) equipped with a personal light recorder. White light intensity, duration above 80, 1000, and 2500 lux, and proportion of red, green, and blue light was depicted by time of the day and season for work days and days off work. Results Indoor workers’ average light exposure only intermittently exceeded 1000 lux during daytime working hours in summer and never in winter. During daytime working hours, most outdoor workers exceeded 2500 lux in summer and 1000 lux in winter. Night workers spent on average 10–50 min >80 lux when working night shifts. During days off work, indoor and night workers were exposed to higher light intensities than during work days and few differences were seen between indoor, outdoor, and night workers. The spectral composition of light was similar for indoor, outdoor, and night workers during days at and off work. Conclusion The night workers of this study were during night hours on average exposed for a limited time to light intensities expected to suppress melatonin. The indoor workers were exposed to light levels during daylight hours that may reduce general well-being and mood, especially in winter. Outdoor workers were during summer daylight hours exposed to light levels comparable to those used for the treatment of depression.

EAR LENGTH AND SPIKELET NUMBER OF WHEAT GROWN AT DIFFERENT TEMPERATURES AND LIGHT INTENSITIES

1965 ◽  
Vol 43 (3) ◽  
pp. 345-353 ◽  
Author(s):  
D. J. C. Friend
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Dry Weight ◽  
High Light ◽  
Morphological Development ◽  
Spikelet Number ◽  
Light Intensities ◽  
Different Temperatures ◽  
Total Plant ◽  
Effects Of Temperature

The number of spikelets on the differentiating inflorescence and the ear at anthesis was highest at high light intensities and at low temperatures. The length of the developing inflorescence and the ear, the height of the main stem, and the total plant dry weight at the time of anthesis were also greatest under these conditions.These results are related to differential effects of temperature and light intensity on the rates and duration of apical elongation, morphological development of the ear, and spikelet formation.

scholarly journals Substrate Acidification by Geranium: Light Effects and Phosphorus Uptake

2008 ◽  
Vol 133 (4) ◽  
pp. 515-520 ◽  
Author(s):  
Matthew D. Taylor ◽  
Paul V. Nelson ◽  
Jonathan M. Frantz
Keyword(s):  
Light Intensity ◽  
Phosphorus Uptake ◽  
Dry Weight ◽  
P Uptake ◽  
High Light Intensity ◽  
High Light ◽  
P Deficiency ◽  
Light Levels ◽  
Direct Light ◽  
Substrate Ph

Sudden pH decline (SPD) describes the situation where crops growing at an appropriate pH rapidly (within 1–2 weeks) cause the substrate pH to shift downward one to two units. ‘Designer Dark Red’ geraniums (Pelargonium ×hortorum Bailey) were grown in three experiments to assess possible effects of light on SPD and phosphorous (P) uptake. The first experiment tested the effect of four light intensities (105, 210, 575, and 1020 ± 25 μmol·m−2·s−1) on substrate acidification. At 63 days, substrate pH declined from 6.0 to 4.8 as light intensity increased. Tissue P of plants grown at the highest two light levels was extremely low (0.10%–0.14% of dry weight). P stress has been reported to cause acidification. Because plants in the two lowest light treatments had adequate P, it was not possible to determine if the drop in substrate pH was a direct light effect or a combination of light and P. The second experiment used a factorial combination of the three highest light levels from Expt. 1 and five preplant P rates (0, 0.065, 0.13, 0.26, or 0.52 g·L−1 substrate) to assess this question. When tissue P concentrations were deficient, pH decreased by 0.6 to 1.0 pH units within 2 weeks and deficiency occurred more often with high light intensity. These data indicated that P deficiency caused substrate acidification and indicated the possibility that P uptake was suppressed by high light intensity. The third experiment was conducted in hydroponics to determine the direct effect of high light intensity on P uptake. In this experiment, cumulative P uptake per gram root and the rate of P uptake per gram root per day both decreased 20% when light intensity increased from 500 to 1100 μmol·m−2·s−1. It is clear from this study that P deficiency causes geraniums to acidify the substrate and that high light suppresses P uptake.

scholarly journals Photoautotrophic Micropropagation of Triploid Melon. I: Sucrose, Light, and CO2 Affect Growth and Net Photosynthetic Rates of Shoot Buds

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 752G-753 ◽  
Author(s):  
Jeffrey Adelberg ◽  
Kazuhiro Fujiwara ◽  
Chalermpol Kirdmanee ◽  
Toyoki Kozai
Keyword(s):  
Interactive Effect ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Photosynthetic Rates ◽  
Shoot Buds ◽  
Light Levels ◽  
Photoautotrophic Micropropagation ◽  
The Media ◽  
L 14 ◽  
Free Media

Growth and net photosynthetic rates of shoots of a triploid melon clone, `(L-14 × B) × L-14', were observed over 21 days following transfer from a multiplication MS medium containing 3% sucrose and 10 μM BA to a shoot development medium containing 1 μM BA at varying levels of sucrose in the medium (0%, 1%, and 3%), and light (50, 100, and 150 PPF) and CO2 (500, 1000, and 1500 ppm) in the headspace. Largest numbers of shoot buds were observed in media with 3% sucrose. Increased light and CO2 had a positive interactive effect. Fresh and dry weights were greatest at highest levels of sucrose, light, and CO2. Although there was less growth in the absence of sucrose, fresh or dry weight of shoot buds grown without sucrose in the media still doubled over the 21 days of culture. Net photosynthetic rates of buds were negative 4 days after initiation of culture and approximately zero after 20 days of treatment. When transferring buds to fresh, sugar-free media, net photosynthetic rates became highly positive. Buds that had been cultured in the absence of sucrose and at highest light levels had the highest net photosynthesis rates upon transfer to fresh, sugar-free media.

Effects of micro-environmental factors on the photoautotrophic growth of Hibiscus sagittifolius Kurz cultured in vitro

2018 ◽  
Vol 39 (4) ◽  
pp. 496-506 ◽  
Author(s):  
Nguyen Thuy Phuong Duyen ◽  
Tran Thi Van ◽  
Nguyen Thu Le Minh ◽  
Nguyen Thi Quynh
Keyword(s):  
Environmental Factors ◽  
Light Intensity ◽  
Leaf Area ◽  
Dark Period ◽  
Dry Weight ◽  
Fresh Weight ◽  
Photoautotrophic Growth ◽  
Temperature Regimes ◽  
Folk Remedy

The arrow leaf abelmoschus rhizome (Hibiscus sagittifolius Kurz), or Sam Bo Chinhin Vietnamese, is a perennial suffrutex herb from which the tuber root is used as a medicine in folk remedy. This species is widely distributed and can be found on many terrains across South East Asia. With an aim to create a large number of uniform and high-quality H. sagittifolius transplants in vitro, effects of some environmental factors such as photoperiod and temperature on the photoautotrophic growth of H. sagittifoliusin vitro plants were investigated. In vitro single nodal cuttings, each with an unfolded leaf, were cultured photoautotrophically (without sucrose and vitamins) on mineral SH medium, under light intensity of 150 µmol m-2 s-1, temperature of 24oC ± 2oC, relative humidity (RH) of 55% ± 5% and three different photoperiods (8, 12 or 16 h d-1) in the first experiment. Commercial polypropylene bags (V = 1,000 ml), attached with two filter-paper membranes, were used as culture vessels. After 42 days of culture, H. sagittifolius plants under the photoperiod of 16 h d-1 had the greatestincreased fresh weight (502.3 mg/plt), increased dry weight (39.5 mg/plt) and leaf area (17.0 cm2) than those put under 8 hd-1or 12 h d-1. In addition, H. sagittifolius plants also showed statistical differences in growth when photoautotrophically cultured in different air temperature regimes, including 28/25oC (photo-/dark period), 25/25oC and 20/25oC. Increased fresh weight (775 mg/plt), increased dry weight (62 mg/plt) and leaf area (22.7 cm2) of in vitro H. sagittifolius plants were the greatest when temperature was maintained at 28 oC during photoperiod. On the contrary, the photoperiod temperature of 20oC resulted in the shortest shoot length and root length of H. sagittifoliusplants. In conclusion, this study proved that H. sagittifolius plants had the best growth when cultured on SH medium, without sucrose and vitamins supplementation, under light intensity of 150 µmol m-2 s-1, RH 55% ± 5%, photoperiod of 16 h d-1, temperature regime of 28/25oC(photo-/dark period). Citation: Nguyen Thuy Phuong Duyen, Tran Thi Van, Nguyen Le Thu Minh, Nguyen Thi Quynh, 2017. Effects of micro-environmental factors on the photoautotrophic growth of Hibiscus sagittifolius Kurz cultured in vitro. Tap chi Sinh hoc, 39(4): 496-506. DOI: 10.15625/0866-7160/v39n4.11030. *Corresponding author: [email protected] 7 September 2017, accepted 15 December 2017

Growth kinetics of Marquis wheat. II. Carbon dioxide dependence

1972 ◽  
Vol 50 (4) ◽  
pp. 883-889 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Carbon Dioxide ◽  
Light Intensity ◽  
Carbon Dioxide Concentration ◽  
Dry Weight ◽  
Maximum Growth ◽  
Carbon Dioxide Enrichment ◽  
Low Light ◽  
Growth Coefficient ◽  
Light Intensities ◽  
Wide Range

Marquis wheat was grown in growth rooms with four different concentrations of carbon dioxide and four to seven different intensities of light in a 16-h photoperiod at 25 °C. Growth was expressed quantitatively as the pseudo-first-order rate coefficient. Carbon dioxide stimulated growth, but the effect was greater the lower the light intensity in opposition to the known effect on photosynthesis. Carbon dioxide and light, in effect, did not influence the "rate" of growth of wheat additively but, rather, mutually compensated over a wide range. The growth coefficient of the roots was a little less than that of the shoots at all carbon dioxide concentrations and light intensities, probably owing to the cost of translocation. However, root growth benefited most from carbon dioxide enrichment at low light intensities. At intermediate light intensity there appeared to be a carbon dioxide concentration optimal for shoot growth. Carbon dioxide enrichment did not influence the maximum growth coefficient of Marquis wheat with respect to light intensity. The light-using efficiency of growth, calculated for vanishingly low light intensity at which it is maximal, was maximal for shoots at 1300 ppm CO2 but that for laminal area and root dry weight increased with CO2 to 2200 ppm at which the value for "leaves" was nearly fourfold that for roots. Unlike photosynthesis, the stimulation of growth by raised CO2 concentration was accomplished by increased efficiency of, and not capacity for, the net photosynthetic use of light.

scholarly journals ACCUMULATION AND METABOLISM OF CARBOHYDRATES IN MARIGOLD SEEDLINGS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 648d-648
Author(s):  
Jack W. Buxton ◽  
Donna Switzer ◽  
Guoqiang Hou
Keyword(s):  
Light Intensity ◽  
Reducing Sugars ◽  
Starch Content ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Night Temperature ◽  
Temperature Regimes ◽  
Lower Light ◽  
Lower Light Intensity

Marigold seedlings, 3 weeks old, were grown in natural light growth chambers at 3 day/night temperature regimes, 8°N/16°D, 13°N/20°D and 18°N/24°D, in a factorial combination with ambient and 1000-1500 ppm CO2. Seedlings were harvested at regular intervals during a 24 hr period and were analyzed for soluble sugars (reducing sugars and sucrose) and starch. Neither temperature nor CO2 concentration affected the accumulation of soluble sugars or starch during the day or night. The soluble sugar concentration ranged from 3% of dry weight at sunrise to 6% at mid-day; the concentration changed little during the night. Light intensity was different during replications of the experiment. Increased light intensity appeared to cause a slight increase in the soluble sugars maintained by the seedling during the day. Accumulated starch increased 6% to 8% from sunrise to late afternoon. Preliminary results indicate that light intensity greatly affected the concentration of starch. On the higher light intensity day, starch accumulated to a maximum of 18% of dry weight; whereas on the lower light intensity day the maximum concentration was 10%. During the night following the lower light intensity day, the starch concentration decreased to approximately 3% by the end of the night; following a brighter day the starch content was 13% at the end of the night.

Adaptations of the photosynthetic apparatus of sun- and shade-grown yellow birch (Betula alleghaniensis Britt.)

1970 ◽  
Vol 48 (9) ◽  
pp. 1681-1688 ◽  
Author(s):  
K. T. Logan
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Dark Respiration ◽  
Photosynthetic Apparatus ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Photosynthetic Rates ◽  
Light Intensities ◽  
Young Leaves ◽  
Sun And Shade

Rates of apparent photosynthesis and dark respiration of 4-year-old yellow birch (Betula alleghaniensis Britt.) seedlings, grown in full light and shade (13% of full light), were measured with an infrared gas analyzer. Measurements were made periodically throughout the growing season, using either attached branches or entire seedlings. Effects of light intensities from 0 to 4500 ft-c on photosynthetic rates were studied, and comparisons made between young and old leaves and between photosynthetic rates in normal (300 p.p.m.) and saturating (1245 p.p.m.) CO2 concentration.The photosynthetic apparatus of yellow birch was found to adapt poorly to shaded conditions. In saturating light, the rate of apparent photosynthesis of young leaves of shade-grown seedlings was only half that of sun-grown seedlings; for old leaves the reduction was even greater. As a result, shade-grown seedlings had a lower photosynthetic capacity in saturating light despite their larger leaf area. In low light intensities, leaves of sun- and shade-grown seedlings had nearly the same rates of apparent photosynthesis. Rates of respiration of shade-grown seedlings were one-half those of sun-grown seedlings.When seedlings were exposed to light intensities comparable to those in which they were grown, their photosynthetic rates correlated with their dry matter production.When the CO2 concentration was raised to 1245 p.p.m., photosynthetic rates of leaves of sun- and shade-grown seedlings increased by the same relative amount. It is concluded that the poor adaptation of yellow birch to shade results from a reduction in content of carboxylating enzymes rather than changes in chlorophyll content or resistance to CO2 diffusion. Adaptations of yellow birch are contrasted with those of sugar maple (Acer saccharum Marsh.).

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