title: Ultraweak Photon Emission from the Seed Coat in Response to Temperature and Humidity-A Potential Mechanism for Environmental Signal Transduction in the Soil Seed Bank.
abstract: Seeds beneath the soil sense the changing environment to time germination and seedling emergence with the optimum time of year for survival. Environmental signals first impact with the seed at the seed coat. To investigate whether seed coats have a role in environmental sensing we investigated their ultraweak photon emission (UPE) under the variable temperature, relative humidity and oxygen conditions they could experience in the soil seed bank. Using a custom-built luminometer we measured UPE intensity and spectra (300-700 nm) from Phaseolus vulgaris seeds, seed coats and cotyledons. UPE was greatest from the internal surface of the seed coat. Seed coat UPE increased concomitantly with both increasing temperature and decreasing relative humidity. Emission was oxygen dependent and it was abolished by treatment with dinitrophenylhydrazine, demonstrating the key role of seed coat carbonyls in the phenomenon. We hypothesize that beneath the soil surface the attenuation of light (virtual darkness: low background noise) enables seeds to exploit UPE for transducing key environmental variables in the soil (temperature, humidity and oxygen) to inform them of seasonal and local temperature patterns. Overall, seed coats were found to have potential as effective transducers of key fluctuating environmental variables in the soil.
authors.affiliation: School of Life Sciences, University of Warwick, Warwickshire, UK. sfootitt@outlook.com.
authors.forename: Steven
authors.initials: S
authors.lastname: Footitt
authors.affiliation: Department of Haematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Palleschi
authors.affiliation: Department of Fundamental and Applied Sciences for Engineering, Sapienza University of Rome, Rome, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Fazio
authors.affiliation: The National Institute for Insurance against Accidents at Work (INAIL), Rome, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Palomba
authors.affiliation: School of Life Sciences, University of Warwick, Warwickshire, UK.
authors.forename: William E
authors.initials: WE
authors.lastname: Finch-Savage
authors.affiliation: Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy.
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Silvestroni
mesh_terms: D006813:Humidity; D008027:Light; D017785:Photons; D000068098:Seed Bank / Q000592:standards*; D012639:Seeds / Q000737:chemistry*; D012987:Soil; D013696:Temperature
chemical_list: D012987:Soil