scholarly journals Distinct Responses to Light in Plants

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 894
Author(s):  
Rita Teresa Teixeira
Keyword(s):  
Light Quality ◽  
Photosynthetic Apparatus ◽  
Spectral Composition ◽  
Light Regulation ◽  
Living Organism ◽  
Life Forms ◽  
The Sun ◽  
Light Duration ◽  
Solar Uv ◽  
Transition To Flowering

The development of almost every living organism is, to some extent, regulated by light. When discussing light regulation on biological systems, one is referring to the sun that has long been positioned in the center of the solar system. Through light regulation, all life forms have evolved around the presence of the sun. As soon our planet started to develop an atmospheric shield against most of the detrimental solar UV rays, life invaded land, and in the presence of water, it thrived. Especially for plants, light (solar radiation) is the source of energy that controls a high number of developmental aspects of growth, a process called photomorphogenesis. Once hypocotyls reach soil′s surface, its elongation deaccelerates, and the photosynthetic apparatus is established for an autotrophic growth due to the presence of light. Plants can sense light intensities, light quality, light direction, and light duration through photoreceptors that accurately detect alterations in the spectral composition (UV-B to far-red) and are located throughout the plant. The most well-known mechanism promoted by light occurring on plants is photosynthesis, which converts light energy into carbohydrates. Plants also use light to signal the beginning/end of key developmental processes such as the transition to flowering and dormancy. These two processes are particularly important for plant´s yield, since transition to flowering reduces the duration of the vegetative stage, and for plants growing under temperate or boreal climates, dormancy leads to a complete growth arrest. Understanding how light affects these processes enables plant breeders to produce crops which are able to retard the transition to flowering and avoid dormancy, increasing the yield of the plant.

scholarly journals Bryophytes on the devastated territories of sulphur deposits and their role in restoration of dump substrate

2018 ◽  
Vol 26 (4) ◽  
pp. 339-353
Author(s):  
I. V. Rabyk ◽  
O. V. Lobachevska ◽  
N. Y. Kyyak ◽  
O. I. Shcherbachenko
Keyword(s):  
Plant Cover ◽  
Photosynthetic Apparatus ◽  
Life Forms ◽  
Climatic Conditions ◽  
Projective Cover ◽  
Biogenic Elements ◽  
Moisture Regime ◽  
Moss Species ◽  
Vegetative Period ◽  
Specific Composition

Bryophytes possess a wide ecological diapason allowing them to populate substrates of technogenic origins which are scarcely suitable or completely unsuitable for viability of vascular plants. 49 bryophyte species, which belong to 2 divisions, 3 classes, 8 orders, 17 families, and 33 genera have been found on the dump territory of sulphur extraction of the mining-chemical enterprise “Sirka” (Yavoriv district, Lviv region). Seven transects, three on the north slope (base, slope, top), three on the south slope and one on the plateau were laid for sample selections. 20 investigated 0.5 × 0.5 m plots located 2 m apart were analyzed within each 10 × 10 m transect. Specific composition, life forms, projective cover, biomass of bryophytes, numbers of male, female and sterile plants, moisture content in the turfs, pH and physiological investigation of mosses were determined on each plot. The quantitative analysis of the biomorphological structure allowed us to establish the dependence of the spread of life forms on exposition and slope height; essential variability of the projective cover and moss biomass. Bryophyte cover plays an essential part in optimization of the moisture regime and surface layer temperature of technogenic substrates, improving the conditions of growth localities. We established that on the dump the dominant moss species are dioecious with a high level of reproductive effort (sexual and sexless), with short ontogenesis and age of first reproduction, which provides the chance to produce the maximum number of progeny in the minimum period and to form a complete moss cover. The analysis of seasonal moss photosynthesis dynamics has demonstrated the adaptability of moss photosynthetic apparatus to contrasting climatic conditions and the ability to support the intensity of photosynthetic processes on a rather stable level during the vegetative period. Our research showed that bryophytes play an important role in productivity of plant cover on the post-technogenic territories of sulphur extraction. It was found that bryophytes play a role in accumulation of organic carbon and biogenic elements in the substrate of the sulphur extraction dump . Carrying out research of specific composition dynamics and species activity is the precondition for revealing the essence of the dynamic processes taking place in the structure of the bryophyte communities on devastated territories and the influence of these processes on the formation of vegetation on dump complexes.

Distribution and ecology of epiphytic bryophytes and lichens in dry evergreen forest of Guyana

1989 ◽  
Vol 5 (2) ◽  
pp. 131-150 ◽  
Author(s):  
J. H. C. Cornelissen ◽  
H. Ter Steege
Keyword(s):  
South America ◽  
Vertical Distribution ◽  
Ecological Study ◽  
Distribution Patterns ◽  
Life Forms ◽  
Evergreen Forest ◽  
The Sun ◽  
Dry Evergreen Forest ◽  
Distribution And Ecology

ABSTRACTA floristic and ecological study of epiphytic bryophytes and lichens on standing mature Eperua trees was carried out in dry evergreen (walaba) forest in Guyana, South America. The trees were sampled from their base up to the highest canopy twigs, using mountaineering techniques. Clear vertical distribution patterns of epiphytic species and life-forms were found. Many species, particularly foliose lichens, appear to be preferential or exclusive to either Eperua grandiflora or E. falcata (Leguminosae), which are the dominant trees in the walaba forest. Special attention is given to the species-rich epiphyte vegetation on the upper canopy twigs, which include two categories of species: the sun epiphytes and the pioneers (facultative epiphylls).

scholarly journals The role of far-red light (FR) in photomorphogenesis and its use in greenhouse plant production

2020 ◽  
Vol 116 (1) ◽  
pp. 93
Author(s):  
Bojka KUMP
Keyword(s):  
Growth And Development ◽  
Light Quality ◽  
Red Light ◽  
Spectral Composition ◽  
Plant Production ◽  
Recent Developments ◽  
Long Time ◽  
Supplementary Lighting ◽  
Quality Of Products

<p>Light energy is one of the most important factors regulating the growth and development of plants. In greenhouses and other controlled- environments in which the natural radiation intensities are often low, plant production relies on supplementary lighting to optimize the photosynthesis, increase production levels, and enable year-round production. For a long time, the research related to artificial lighting sources focused on the optimization of the efficiency of use for photosynthesis. The quality of light in plant production has been widely addressed only recently with the development of advanced LED technology that is energy efficient and enables the control of the spectral composition of light. Red and far-red light are sensed by the phytochromes that trigger several morphological and developmental processes that impact productivity and yield quality. Thus, to efficiently exploit all the advantages of LEDs and to develop LED arrays for specific plant applications, it is essential to understand thoroughly how light quality influences plant growth and development. This paper presents an overview of the recent developments in light quality manipulation, focusing on far-red light and the R: FR ratio, to improve yield and quality of products and to manage plant architecture and flowering in vegetable and ornamental horticulture.</p>

scholarly journals 160 m Pulsations in the Magnetosphere of the Earth Possibly Caused by Oscillations of the Sun

1983 ◽  
Vol 66 ◽  
pp. 451-455
Author(s):  
B.M. Vladimirsky ◽  
V.P. Bobova ◽  
N.M. Bondarenko ◽  
V.K. Veretennikova
Keyword(s):  
Uv Radiation ◽  
Wavelength Range ◽  
Optical Observations ◽  
Stable Phase ◽  
Expansion Velocity ◽  
The Sun ◽  
Flux Variation ◽  
Geophysical Observatory ◽  
The Earth ◽  
Solar Uv

AbstractThe measurements of the amplitudes envelope of Pc 3–4 geomagnetic micropulsations obtained at the Borok Geophysical Observatory were analysed by the cosinor method to search for magnetospheric pulsations with a period of about 160 m. 216 days of observations in 1974–1978 were used. It was found that Pc3–4 amplitudes are modulated by the period 160.010 m with a stable phase. The maximum of the Pc3–4 amplitudes follows approximately 20 m after the maximum of the solar expansion velocity (for the center of the disk) in the optical observations of Severny et al. This modulation of the Pc3–4 amplitudes could be caused by the presence of an oscillating component in solar UV radiation over the wavelength range 100-900 Å. The amplitude of the UV flux variation may be as large as 2–4%.

scholarly journals The Role of Chloroplast Membrane Lipid Metabolism in Plant Environmental Responses

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 706
Author(s):  
Ron Cook ◽  
Josselin Lupette ◽  
Christoph Benning
Keyword(s):  
Environmental Conditions ◽  
Environmental Changes ◽  
Photosynthetic Apparatus ◽  
Life Forms ◽  
Membrane Lipid ◽  
Chloroplast Membrane ◽  
Class Composition ◽  
Environmental Responses

Plants are nonmotile life forms that are constantly exposed to changing environmental conditions during the course of their life cycle. Fluctuations in environmental conditions can be drastic during both day–night and seasonal cycles, as well as in the long term as the climate changes. Plants are naturally adapted to face these environmental challenges, and it has become increasingly apparent that membranes and their lipid composition are an important component of this adaptive response. Plants can remodel their membranes to change the abundance of different lipid classes, and they can release fatty acids that give rise to signaling compounds in response to environmental cues. Chloroplasts harbor the photosynthetic apparatus of plants embedded into one of the most extensive membrane systems found in nature. In part one of this review, we focus on changes in chloroplast membrane lipid class composition in response to environmental changes, and in part two, we will detail chloroplast lipid-derived signals.

scholarly journals Seeing the Light: The Roles of Red- and Blue-Light Sensing in Plant Microbes

2018 ◽  
Vol 56 (1) ◽  
pp. 41-66 ◽  
Author(s):  
Gwyn A. Beattie ◽  
Bridget M. Hatfield ◽  
Haili Dong ◽  
Regina S. McGrane
Keyword(s):  
Blue Light ◽  
Molecular Mechanisms ◽  
Red Light ◽  
Light Availability ◽  
Photosynthetic Apparatus ◽  
Light Regulation ◽  
Environmental Signals ◽  
Light Sensing ◽  
Fungal Phytopathogens ◽  
Bacteria And Fungi

Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage) domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont. Bacterial LOV proteins also influence light-mediated changes in both symbiotic and pathogenic phenotypes. Although red-light sensing by fungal phytopathogens is poorly understood, fungal LOV proteins contribute to blue-light regulation of traits, including asexual development and virulence. Collectively, these studies highlight that plant microbes have evolved to exploit light cues and that light sensing is often coupled with sensing other environmental signals.

Life expectancy and life energy according to Evo-SETI theory

2018 ◽  
Vol 18 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Mathematical Theory ◽  
Physical Phenomenon ◽  
Living Organism ◽  
Strict Sense ◽  
Power Curve ◽  
The Sun ◽  
Normalization Condition ◽  
Straight Line ◽  
Least Energy ◽  
Living Creature

AbstractThis paper is profoundly innovative for the Evo-SETI (Evolution and SETI) mathematical theory. While this author's previous papers were all based on the notion of a b-lognormal, that is a probability density function in the time describing one's life between birth and ‘senility’ (the descending inflexion point), in this paper the b-lognormals range between birth and peak only, while a descending parabola covers the lifespan after the peak and down to death. The resulting finite curve in time is called a LOGPAR, a nickname for ‘b-LOGnormal and PARabola’. The advantage of such a formulation is that three variables only (birth, peak and death) are sufficient to describe the whole Evo-SETI theory and the senility is discarded forever and so is the normalization condition of b-lognormals: only the shape of the b-lognormals is kept between birth and peak, but not its normalization condition.In addition, further advantages exist:1) The notion of ENERGY becomes part of Evo-SETI theory. This is in addition to the notion of ENTROPY already contained in the theory as the Shannon Information Entropy of b-lognormals, as it was explored in this author's previous papers. Actually, the LOGPAR may now be regarded as a POWER CURVE, i.e. a curve expressing the power of the living being to which it refers. And this power is to be understood both in the strict sense of physics (i.e. a curve measured in Watts) and in the loose sense of ‘political power’ if the logpar refers to a Civilization.Then the integral in the time of this power curve is, of course, the ENERGY either absorbed or produced by the physical phenomenon that the LOGPAR is describing in the time. For instance, if the logpar shows the time evolution of the Sun over about 10 billion years, the integral of such a curve is the energy produced by the Sun over the whole of its lifetime. Or, if the logpar describes the life of a man, the integral is the energy that this man must use in order to live.2) The PRINCIPLE OF LEAST ENERGY, reminiscent of the Principle of Least Action, i.e. the key stone to all Physics, also enters now into the Evo-SETI Theory by virtue of the so-called LOGPAR HISTORY FORMULAE, expressing the b-lognormal's mu and sigma directly in terms of the three only inputs b, p, d. The optimization of the lifetime of a living creature, or of a Civilization, or of a star, is obtained by setting to zero the first derivative of the area under the logpar power curve with respect to sigma. That yields the best value of both mu and sigma fulfilling the Principle of Least Energy for Evo-SETI Theory.3) We also derive for the first time a few more mathematical equations related to the ‘adolescence’ (or ‘puberty’) time, i.e. the time when the living organism acquires the capability of producing offsprings. This time is defined as the abscissa of ascending inflection point of the b-lognormal between birth and peak. In addition, we prove that the straight line parallel to the time axis and departing from the puberty time comes to mean the ‘Fertility Span’ in between puberty and the EOF (End-Of-Fertility time), which is where the above straight line intersects the descending parabola. All these new results apply well to the description of Man as the living creature to which our Evo-SETI mathematical theory perfectly applies.In conclusion, this paper really breaks new mathematical ground in Evo-SETI Theory, thus paving the way to further applications of the theory to Astrobiology and SETI.

scholarly journals Welcome to the Arbustocene

2005 ◽  
Vol 11 (2) ◽  
pp. 77 ◽  
Author(s):  
Harry F. Recher ◽  
Paul R. Ehrlich
Keyword(s):  
Global Climate Change ◽  
Mass Extinction ◽  
Global Climate ◽  
Chemical Change ◽  
Life Forms ◽  
The Sun ◽  
Evolution Of Life ◽  
Insufficient Time ◽  
Biophysical Environment ◽  
Evolution Of Photosynthesis

The beginning and end of each geological epoch is marked by a major, often cataclysmic, event affecting Earth?s biophysical environment. Most often major periods in Earth?s history requiring a new epoch to be named are remarkable by the mass extinction of dominant life forms and their eventual replacement by new groups of organisms which then dominate Earth?s ecosystems. Only once in pre-history were these spectacular evolutionary events precipitated by a physical or chemical change to Earth?s atmosphere as a result of biological activity. This occurred early in Earth?s history with the release of ?polluting? oxygen after the evolution of photosynthesis. More frequently, punctuations in the evolution of life have been brought on by some virtually instantaneous disruption to climate by extreme volcanic activity or an asteroid strike, such as that which heralded the end of dinosaurs and the dawn of the age of mammals. In these instances, changes to the capacity of Earth?s atmosphere to absorb and reflect light and heat from the Sun initiated a period of rapid global climate change leaving insufficient time for organisms to migrate or adapt.

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