RESUMO
Background: A brief review is given of Peter W. Barlows' contributions to research on gravity tide-related phenomena in plant biology, or 'selenonastic' effects as he called them, including his early research on root growth. Also, new results are presented here from long-term recordings of spontaneous ultra-weak light emission during germination, reinforcing the relationship between local lunisolar tidal acceleration and seedling growth. Scope: The main ideas and broad relevance of the work by Barlow and his collaborators about the effects of gravity on plants are reviewed, highlighting the necessity of new models to explain the apparent synchronism between root growth and microscale gravity changes 107 times lower than that exerted by the Earth's gravity. The new results, showing for the first time the germination of coffee beans in sequential tests over 2 months, confirm the co-variation between the patterns in ultra-weak light emission and the lunisolar tidal gravity curves for the initial growth phase. For young sprouts (<1 month old), the rhythm of growth as well as variation in light emission exhibit the once a day and twice a day periodic variations, frequency components that are the hallmark of local lunisolar gravimetric tides. Although present, this pattern is less pronounced in coffee beans older than 1 month. Conclusions: The apparent co-variation between ultra-weak light emission and growth pattern in coffee seedlings and the lunisolar gravity cycles corroborate those previously found in seedlings from other species. It is proposed here that such patterns may attenuate with time for older sprouts with slow development. These data suggest that new models considering both intra- and intercellular interactions are needed to explain the putative sensing and reaction of seedlings to the variations in the gravimetric tide. Here, a possible model is presented based on supracellular matrix interconnections.
Assuntos
Coffea/fisiologia , Germinação/fisiologia , Gravitação , Luz , Fenômenos Fisiológicos Vegetais , História do Século XX , História do Século XXIRESUMO
In order to corroborate the hypothesis that variations in the rate of spontaneous ultra-weak photon emission (UPE) from germinating seedlings are related to local variations of the lunisolar tidal force, a series of simultaneous tests was performed using the time courses of UPE collected from three plant species-corn, wheat and sunflower-and also from wheat samples whose grains were transported between continents, from Brazil to The Netherlands and vice versa. All tests which were run in parallel showed coincident inflections within the UPE time courses not only between seedlings of the same species but also between the different species. In most cases, the UPE inflections were synchronised with the turning points in the local gravimetric tidal variation. Statistical tests using the local Pearson correlation verified these coincidences in the two time series. The results therefore support the hypothesis of a relationship between UPE emissions and, in the oscillations, the local gravimetric tide. This applies to both the emissions from seedlings of different species and to the seedlings raised from transported grain samples of the same species.
Assuntos
Gravitação , Internacionalidade , Fótons , Plantas/metabolismo , Plântula/metabolismo , Especificidade da Espécie , Fatores de TempoRESUMO
Measurements of spontaneous ultra-weak light (biophoton) emission from native Brazilian and German wheat seedlings in three simultaneous series of germination tests are presented, two run in Germany and one in Brazil. Seedlings in both countries presented semi-circadian rhythms of emission that were in accordance with the local lunisolar gravimetric tidal acceleration, as did seeds which had been transported from Brazil to Germany. The simultaneity of the photon emission patterns in all tests argues for the lunisolar tide and its rhythmic variations as regulators of the natural rhythm of photon emission. However, seedlings from seed samples transported from Brazil to Germany showed, in addition, a temporary disturbance within the emission periodicity which may indicate a possible short-term acclimatization to the new location.
Assuntos
Germinação , Plântula/fisiologia , Triticum/fisiologia , Aclimatação , Brasil , Ritmo Circadiano , Alemanha , Lua , Fótons , Ondas de MaréRESUMO
Semi-circadian rhythms of spontaneous photon emission from wheat seedlings germinated and grown in a constant environment (darkened chamber) were found to be synchronized with the rhythm of the local gravimetric (lunisolar) tidal acceleration. Time courses of the photon-count curves were also found to match the growth velocity profile of the seedlings. Pair-wise analyses of the data--growth, photon count, and tidal--by local tracking correlation always revealed significant coefficients (P > 0.7) for more than 80% of any of the time periods considered. Using fast Fourier transform, the photon-count data revealed periodic components similar to those of the gravimetric tide. Time courses of biophoton emissions would appear to be an additional, useful, and innovative tool in both chronobiological and biophysical studies.
Assuntos
Ritmo Circadiano , Luz , Fótons , Plântula/fisiologia , Triticum/fisiologia , Plântula/crescimento & desenvolvimento , Fatores de Tempo , Triticum/crescimento & desenvolvimentoRESUMO
The recovery of an optical carrier with the deletion of its amplitude modulation is introduced using a deeply saturated ultra-long semiconductor optical amplifier (UL-SOA). The experimental results were achieved for input signal bit rates up to 12.5 Gbps with high extinction ratio (up to 13.9 dB). The influence of parameters such as UL-SOA bias current, optical bandwidth, signal input power, modulation depth and bit rate are analyzed including the carrier spectral broadening effects due to the self-phase modulation effect.