Peter Barlow’s insights and contributions to the study of tidal gravity variations and ultra-weak light emissions in plants

Abstract

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.

Full moonlight-induced circadian clock entrainment in Coffea arabica

“…Lunisolar tide influences plant phenomena such as leaf movement, stem elongation, fluctuations in tree stem diameter, root growth, biophoton emission by seedlings, and chlorophyll fluorescence [3]. Recently, Gallep and coworkers demonstrated co-variation between ultra-weak light emission, coffee seedling growth patterns and lunisolar gravity cycles [4]. These authors corroborated results previously found in seedlings of other species [3].…”

The botanical multiverse of Peter Barlow

“…Their suggestion involves mechanoreceptive molecular mechanisms that are not localized within one cell only, but have a 'supracellular' dimension [122]. Arguably, already anticipated by Barlow [123], Gallep et al [122] propose that ensembles of amyloplasts are mechanically connected by cytoskeletal filaments (or other, as yet undescribed, structures) operating together across several adjacent cells.…”

“…Gallep et al [122] present an important review of Peter's achievements with respect to the effects of lunisolar tidal forces on plants, including spontaneous ultraweak emissions from plants. Importantly, they show how his extra-terrestrial interests developed naturally from his more Earth-bound pursuits, which give insights into Peter's thinking on these matters.…”

“…The data support the notion that gravimetric tide minima and maxima affect the UPE of seedlings, but, as seedlings mature, the periodic components of the gravimetric tide become gradually less pronounced. A particular strength of this paper is that Gallep et al [122] consider an explanation of how small changes in local gravity can have an effect on the growth of seedlings. And they propose a mechanism for sensing microgravity forces involving amyloplasts (which is consistent with Earth-bound graviperception by roots), or other dense structures [122].…”

“…Arguably, already anticipated by Barlow [123], Gallep et al [122] propose that ensembles of amyloplasts are mechanically connected by cytoskeletal filaments (or other, as yet undescribed, structures) operating together across several adjacent cells. Gallep et al [122] also speculate that sensitivity to microscale gravity variation could involve the mesoscopic action of water, since coherently organized and mobile clusters of water could provide electricalmechanical input to cells in response to conformational or positional changes induced by the gravimetric tide (a notion previously explored by Barlow in 2012 [112]). Water is important not only within cells but also in their cell walls, forming a super-symplasmic continuum that permeates the whole plant body.…”