scholarly journals Operation of Laboratory Photobioreactors with Online Growth Measurements and Customizable Light Regimes

10.3791/62910 ◽  
2021 ◽  
Author(s):  
Marianne Haines ◽  
Marc Strous
Keyword(s):  
Light Regimes

INFLUENCE OF WEEKLY CHANGES IN TEMPERATURE AND LIGHT REGIMES ON THE INCIDENCE OF BLOTCHY RIPENING OF TOMATOES

1974 ◽  
Vol 54 (1) ◽  
pp. 129-133
Author(s):  
T. MATSUMOTO ◽  
C. A. HORNBY
Keyword(s):  
Cumulative Effect ◽  
Controlled Environment ◽  
Diurnal Changes ◽  
Light Regimes ◽  
Common Trend ◽  
Cloudy Weather ◽  
Two Factors ◽  
Temperature Levels ◽  
Greenhouse Tomatoes ◽  
Compensatory Effect

The hypothesis that blotchy ripening (BR) of greenhouse tomatoes (Lycopersicon esculentum Mill.) was associated with a cumulative effect of alternating periods of bright sunshine and cloudy weather was tested in controlled environment chambers. Temperatures were programed to give diurnal changes between 11.7 C/26.7 C night/day representing sunny days, and 11.7 C/21.2 C night/day for cloudy days. The two levels of light were (1) 18,299 lx for sunny days, and (2) 16,656 lx for cloudy days. These two factors were combined in four regimes to represent (1) sunny-day temperature and light; (2) sunny-day temperature and alternate weeks of sunny-day and cloudy-day light; (3) alternate weeks of sunny-day and cloudy-day temperature and sunny-day light; and (4) alternate weeks of sunny-day temperature and light, and cloudy-day temperature and light. Four series of plants showed a common trend. Consistent sunny-day temperature and alternating weeks of sunny or cloudy-day light produced the highest incidence of BR. Alternating weeks of temperature levels with consistent sunny-day light produced less BR but not significantly so. When sunny-day temperature and light were alternated weekly with cloudy day conditions, there was a reduced percentage of BR and less severe symptoms. This regime suggests a compensatory effect when temperature is varied directly with changes in light intensity. The regime for consistent sunny-day temperature and light gave the lowest BR incidence with mild symptoms.

scholarly journals The effects of light regimes and hormones on corneal growth in vivo and in organ culture

2011 ◽  
Vol 219 (6) ◽  
pp. 766-775 ◽  
Author(s):  
Christina Wahl ◽  
Tong Li ◽  
Yuko Takagi ◽  
Howard Howland
Keyword(s):  
Organ Culture ◽  
Light Regimes

Do changes in light direction affect absorption profiles in leaves?

2010 ◽  
Vol 37 (5) ◽  
pp. 403 ◽  
Author(s):  
Craig R. Brodersen ◽  
Thomas C. Vogelmann
Keyword(s):  
Cross Sections ◽  
Incident Light ◽  
Monochromatic Light ◽  
Diffuse Light ◽  
Spongy Mesophyll ◽  
Light Regimes ◽  
Direct Light ◽  
Direct Measurements ◽  
Leaf Level

Leaf anatomy plays a functional role in propagating light through the leaf; palisade mesophyll has been shown to facilitate the channelling of collimated light deeper into the spongy mesophyll. Direct measurements of the propagation of diffuse light into the leaf, however, are absent. Using chlorophyll fluorescence imaging of leaf cross-sections, we measured light absorption profiles in leaves under direct (collimated), diffuse and low-angle monochromatic light. Low-angle and diffuse light was absorbed closer to the irradiated surface than direct light perpendicular to the surface. The shapes of internal absorption profiles indicated that leaves were influenced by the directional quality of the incident light. In addition, absorption profiles revealed that leaves were not simple light absorbing objects and that cellular anatomy influences the direction of light travelling into the mesophyll. These findings also suggest a mechanism for previously measured differences in leaf level photosynthesis under opposing light regimes.

Development of an algal treatment system for Se removal: Effects of light regimes, nutrients, sulfate and hypersalinity

Chemosphere ◽  
2016 ◽  
Vol 164 ◽  
pp. 372-378 ◽  
Author(s):  
Fang Liu ◽  
Jung-Chen Huang ◽  
Chuanqi Zhou ◽  
Shengbing He ◽  
Weili Zhou
Keyword(s):  
Treatment System ◽  
Light Regimes

Control of morphogenesis in the gametophyte of a fern by light and growth hormones

1980 ◽  
Vol 58 (13) ◽  
pp. 1464-1473 ◽  
Author(s):  
Piyush Swami ◽  
V. Raghavan
Keyword(s):  
Abscisic Acid ◽  
Blue Light ◽  
Red Light ◽  
Basal Medium ◽  
Cell Number ◽  
Growth Hormones ◽  
Dichlorophenoxyacetic Acid ◽  
Light Regimes ◽  
Lygodium Japonicum ◽  
2,4 Dichlorophenoxyacetic Acid

The effects of 2,4-dichlorophenoxyacetic acid (2,4-D), gibberellic acid (GA), and abscisic acid (ABA) on the morphogenesis of gametophytes of Lygodium japonicum growing as longer-than-broad biplanar plates in red light and as broader-than-long biplanar plates in blue light were studied. Addition of 2,4-D or GA to the medium induced a change in the form of gametophytes from biplanar to filamentous in red light. Gametophytes growing in a medium containing 2,4-D in blue light were longer than broad, very much like gametophytes growing in the basal medium in red light. Although ABA generally retarded the growth of gametophytes in both light regimes, its presence in a medium containing 2,4-D nullified the effect of the latter, causing gametophytes to become plate-like in red light and short and stunted in blue light. Changes in the morphology of gametophytes induced by growth hormones were accompanied by corresponding changes in their length:width ratio and cell number.

scholarly journals Physical characterization of Rhipsalis (Cactaceae) fruits and seeds germination in different temperatures and light regimes

2016 ◽  
Vol 76 (2) ◽  
pp. 367-373 ◽  
Author(s):  
A. B. Lone ◽  
R. C. Colombo ◽  
B. L. G. Andrade ◽  
L. S. A. Takahashi ◽  
R. T. Faria
Keyword(s):  
Seed Germination ◽  
Germination Percentage ◽  
Light Regimes ◽  
Total Absence ◽  
Germination Characteristics ◽  
Different Temperatures ◽  
Medium Time ◽  
Seeds Germination

Abstract The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

scholarly journals Physiological responses of two tropical weeds to shade: I. Growth and biomass allocation

1999 ◽  
Vol 34 (6) ◽  
pp. 944-952 ◽  
Author(s):  
Moacyr Bernardino Dias-Filho
Keyword(s):  
Leaf Area ◽  
Weed Management ◽  
Dry Mass ◽  
High Light ◽  
Low Light ◽  
Light Regimes ◽  
Leaf Dry Mass ◽  
Lower Ability ◽  
Total Plant ◽  
Plant Dry Mass

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in Brazilian Amazonia, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. For both species leaf dry mass and leaf area per total plant dry mass, and leaf area per leaf dry mass were higher for low-light plants, whereas root mass per total plant dry mass was higher for high-light plants. High-light S. cayennensis allocated significantly more biomass to reproductive tissue than low-light plants, suggesting a probably lower ability of this species to maintain itself under shaded conditions. Relative growth rate (RGR) in I. asarifolia was initially higher for high-light grown plants and after 20 days started decreasing, becoming similar to low-light plants at the last two harvests (at 30 and 40 days). In S. cayennensis, RGR was also higher for high-light plants; however, this trend was not significant at the first and last harvest dates (10 and 40 days). These results are discussed in relation to their ecological and weed management implications.

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