Changes in the responses to light quality during ontogeny in Chenopodium album

2003 ◽  
Vol 81 (2) ◽  
pp. 152-163 ◽  
Author(s):  
Humberto Fabio Causin ◽  
Renata D Wulff
Keyword(s):  
Plant Growth ◽  
Light Quality ◽  
Chenopodium Album ◽  
Intraspecific Variability ◽  
Reproductive Fitness ◽  
Stem Length ◽  
Shade Avoidance ◽  
Late Flowering ◽  
Total Leaf ◽  
Avoidance Responses

Morphological shade-avoidance responses have been hypothesized to be a form of adaptive plasticity to improve competition for light; however, little is known about their intraspecific variability and their effect on reproductive fitness. To compare plant responses either at a common age or at a common phenological stage, two experiments were conducted with early- and late-flowering Chenopodium album plants exposed to different red (660 nm) to far red (730 nm) ratios. In the first experiment, plant height and number of leaves were recorded at several times during the vegetative stage, and at the onset of flowering, each plant was harvested and other growth traits were measured. In the second experiment, three destructive harvests were performed across the whole plant cycle. Plant growth and development markedly differed between early- and late-flowering plants in all of the conditions tested. Light treatments significantly affected stem length, total leaf number, total leaf area, and relative allocation to leaf biomass. In all families, the response of stem elongation to light treatments decreased later in the development, while changes in the other plastic responses were mostly due to variations in plant growth. No significant treatment effect was found on relative biomass allocation to reproductive structures. However, individual seed mass significantly differed between certain groups, indicating that light quality can affect reproductive fitness through changes in traits other than fruit or seed set.Key words: Chenopodium album, fitness, intraspecific variability, phenotypic plasticity, red to far red ratio, shade-avoidance responses.

scholarly journals Identification and expression of the trehalose-6-phosphate synthase gene family members in tomato exposed to different light spectra

2017 ◽  
Vol 69 (1) ◽  
pp. 93-101
Author(s):  
Zexiong Chen ◽  
Juan Lou
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
White Light ◽  
Growth And Development ◽  
Light Quality ◽  
Red Light ◽  
Floral Transition ◽  
Stem Length ◽  
Pcr Analysis ◽  
Phosphate Synthase

Light is the source of energy for plants. Light wavelengths, densities and irradiation periods act as signals directing morphological and physiological characteristics during plant growth and development. To evaluate the effects of light wavelengths on tomato growth and development, Solanum lycopersicum (cv. micro-Tom) seedlings were exposed to different light-quality environments, including white light and red light supplemented with blue light (at ratios of 3:1 and 8;1, respectively). Tomatoes grown under red light supplemented with blue light displayed significantly shorter stem length, a higher number of flower buds and rate of fruit set, but an extremely late flowering compared to white-light-grown plants. To illustrate the mechanism underlying the inhibition of stem growth and floral transition mediated by red/blue light, 10 trehalose-6-phosphate synthase (TPS) genes were identified in tomato, and bioinformatics analysis was performed. qRT-PCR analysis showed that SlTPSs were expressed widely throughout plant development and SlTPS1 was expressed at extremely high levels in stems and buds. Further analysis of several flowering-associated genes and microRNAs showed that the expressions of SlTPS1, SlFT and miR172 were significantly downregulated in tomato grown under red and blue light compared with those grown under white light, whereas miR156 transcript levels were increased. A regulatory model underlying vegetative growth and floral transition regulated by light qualities is presented. Our data provide evidence that light quality strongly affects plant growth and phase transition, most likely via the TPS1-T6P signaling pathway.

scholarly journals Phytochrome contributes to blue-light-mediated stem elongation and associated shade-avoidance response in mature Arabidopsis plants

2020 ◽  
Author(s):  
Yun Kong ◽  
Youbin Zheng
Keyword(s):  
Avoidance Response ◽  
Blue Light ◽  
Stem Elongation ◽  
Growth Trait ◽  
Stem Length ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Shade Avoidance ◽  
Wild Type ◽  
Avoidance Responses

AbstractOur recent studies on ornamental plants and microgreens indicate that blue-light-mediated stem elongation is related to phytochrome activity, which was based on the calculated phytochrome photoequilibrium. To examine whether phytochromes really contribute to the blue light’s effect, plant phenotypic responses were investigated in wild type Arabidopsis (Col-0), and its quintuple phytochrome (phyA phyB phyC phyD phyE) mutant plants under the following light treatments: (1) R, a pure red light from 660-nm LED; (2) B, a pure blue light from 455-nm LED; (3) BR, a impure blue light from LED combination of 94% B and 6% R; and (4) BRF, another impure blue light from LED combination of BR and 6 µmol m−2 s−1 of FR (735 nm). For all the light treatments, a photosynthetic photon flux density of ≈100 μmol m−2 s−1 were provided by 24-h lighting daily inside a walk-in growth chamber, which had an air temperature of ≈ 23 °C. The calculated phytochrome photoequilibrium was 0.89, 0.50, 0.69, and 0.60 for R, B, BR, and BRF, respectively, indicating a higher phytochrome activity under R and BR than B and BRF. After 18 days of light treatment, B or BRF increased main stem length in wild-type plants compared with R, but BR had an inhibition effect similar to R. Also, B and BRF relative to R or BR induced earlier flowering and reduced leaf size in wild type plants, showing typical shade-avoidance responses. In phytochrome-deficient mutant plants, the above shade-avoidance responses were inhibited under B or BRF, and induced under BR. However, as an exception, hypocotyl length, a growth trait during the de-etiolation stage, was reduced under B, BR and BRF vs. R regardless of phytochrome absence. It suggests that for mature Arabidopsis plants, phytochrome plays an active role in blue-light-mediated stem elongation and associated shade-avoidance response.

Phytochrome contributes to blue-light-mediated stem elongation and flower initiation in mature Arabidopsis thaliana plants

2021 ◽  
Author(s):  
Yun Kong ◽  
Youbin Zheng
Keyword(s):  
Arabidopsis Thaliana ◽  
Blue Light ◽  
Stem Elongation ◽  
Growth Trait ◽  
Stem Length ◽  
Photon Flux ◽  
Flower Initiation ◽  
Shade Avoidance ◽  
Wild Type ◽  
Avoidance Responses

To examine whether phytochromes contribute to blue-light-mediated stem elongation, plant phenotypic responses were investigated in wild type Arabidopsis thaliana (Col-0), and its quintuple phytochrome (phyA phyB phyC phyD phyE) mutant plants under the following light treatments: (1) R, a pure red light from 660-nm LED; (2) B, a pure blue light from 455-nm LED; (3) BR, a impure blue light from LED combination of 94% B and 6% R; and (4) BRF, another impure blue light from LED combination of BR and 6 µmol m−2 s−1 of FR (735 nm). A photosynthetic photon flux density of ≈100 μmol m−2 s−1 was provided for all the light treatments. The calculated phytochrome photoequilibrium was 0.89, 0.50, 0.69, and 0.60 for R, B, BR, and BRF, respectively, indicating a higher phytochrome activity under R and BR than B and BRF. After 18 days of light treatment, B or BRF increased main stem length in wild-type plants compared with R, but BR had an inhibition effect similar to R. Also, B and BRF relative to R or BR induced earlier flowering and reduced leaf size in wild type plants, showing typical shade-avoidance responses. In phytochrome-deficient mutant plants, the above shade-avoidance responses were inhibited under B or BRF. However, hypocotyl length, a growth trait characterizing the de-etiolation stage, was reduced under B, BR and BRF vs. R regardless of phytochrome absence. These findings suggest that for mature Arabidopsis plants, phytochrome plays a role in blue-light-mediated stem elongation and the associated shade-avoidance responses.

scholarly journals Multiple Pathways in the Control of the Shade Avoidance Response

Plants ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 102 ◽  
Author(s):  
Giovanna Sessa ◽  
Monica Carabelli ◽  
Marco Possenti ◽  
Giorgio Morelli ◽  
Ida Ruberti
Keyword(s):  
Avoidance Response ◽  
Light Quality ◽  
Developmental Stages ◽  
Relative Fitness ◽  
Shade Avoidance ◽  
Signaling Mechanisms ◽  
Similarities And Differences ◽  
Growth Development ◽  
Molecular Description ◽  
New Strategies

To detect the presence of neighboring vegetation, shade-avoiding plants have evolved the ability to perceive and integrate multiple signals. Among them, changes in light quality and quantity are central to elicit and regulate the shade avoidance response. Here, we describe recent progresses in the comprehension of the signaling mechanisms underlying the shade avoidance response, focusing on Arabidopsis, because most of our knowledge derives from studies conducted on this model plant. Shade avoidance is an adaptive response that results in phenotypes with a high relative fitness in individual plants growing within dense vegetation. However, it affects the growth, development, and yield of crops, and the design of new strategies aimed at attenuating shade avoidance at defined developmental stages and/or in specific organs in high-density crop plantings is a major challenge for the future. For this reason, in this review, we also report on recent advances in the molecular description of the shade avoidance response in crops, such as maize and tomato, and discuss their similarities and differences with Arabidopsis.

scholarly journals Subtle variation in shade avoidance responses may have profound consequences for plant competitiveness

2017 ◽  
Vol 121 (5) ◽  
pp. 863-873 ◽  
Author(s):  
Franca J Bongers ◽  
Ronald Pierik ◽  
Niels P R Anten ◽  
Jochem B Evers
Keyword(s):  
Shade Avoidance ◽  
Avoidance Responses

Phytochrome A inhibits shade avoidance responses under strong shade through repressing the brassinosteroid pathway in Arabidopsis

2020 ◽  
Vol 104 (6) ◽  
pp. 1520-1534
Author(s):  
Bin Song ◽  
Hongli Zhao ◽  
Kangmei Dong ◽  
Meiling Wang ◽  
Shujuan Wu ◽  
...  
Keyword(s):  
Shade Avoidance ◽  
Phytochrome A ◽  
Avoidance Responses

scholarly journals Reaching Natural Growth: Light Quality Effects on Plant Performance in Indoor Growth Facilities

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1273
Author(s):  
Camilo Chiang ◽  
Daniel Bånkestad ◽  
Günter Hoch
Keyword(s):  
Plant Growth ◽  
Field Trial ◽  
Light Quality ◽  
Plant Traits ◽  
Principal Component ◽  
Biomass Productivity ◽  
Plant Performance ◽  
Plant Responses ◽  
Natural Ecosystems ◽  
Species Specific

To transfer experimental findings in plant research to natural ecosystems it is imperative to reach near to natural-like plant performance. Previous studies propose differences in temperature and light quantity as main sources of deviations between indoor and outdoor plant growth. With increasing implementation of light emitting diodes (LED) in plant growth facilities, light quality is yet another factor that can be optimised to prevent unnatural plant performance. We investigated the effects of different wavelength combinations in phytotrons (i.e., indoor growth chambers) on plant growth and physiology in seven different plant species from different plant functional types (herbs, grasses and trees). The results from these experiments were compared against a previous field trial with the same set of species. While different proportions of blue (B) and red (R) light were applied in the phytotrons, the mean environmental conditions (photoperiod, total radiation, red to far red ratio and day/night temperature and air humidity) from the field trial were used in the phytotrons in order to assess which wavelength combinations result in the most natural-like plant performance. Different plant traits and physiological parameters, including biomass productivity, specific leaf area (SLA), leaf pigmentation, photosynthesis under a standardised light, and the respective growing light and chlorophyll fluorescence, were measured at the end of each treatment. The exposure to different B percentages induced species-specific dose response reactions for most of the analysed parameters. Compared with intermediate B light treatments (25 and/or 35% B light), extreme R or B light enriched treatments (6% and 62% of B respectively) significantly affected the height, biomass, biomass allocation, chlorophyll content, and photosynthesis parameters, differently among species. Principal component analyses (PCA) confirmed that 6% and 62% B light quality combinations induce more extreme plant performance in most cases, indicating that light quality needs to be adjusted to mitigate unnatural plant responses under indoor conditions.

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