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Journal articles on the topic 'Plant hypergravity'

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Author: Grafiati

Published: 10 March 2023

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1

Hattori, Takayuki, Kouichi Soga, Kazuyuki Wakabayashi, and Takayuki Hoson. "An Arabidopsis PTH2 Gene Is Responsible for Gravity Resistance Supporting Plant Growth under Different Gravity Conditions." Life 12, no. 10 (October 14, 2022): 1603. http://dx.doi.org/10.3390/life12101603.

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Terrestrial plants respond to and resist gravitational force. The response is termed “gravity resistance”, and centrifugal hypergravity conditions are efficient for investigating its nature and mechanism. A functional screening of Arabidopsis T-DNA insertion lines for the suppression rate of elongation growth of hypocotyls under hypergravity conditions was performed in this study to identify the genes required for gravity resistance. As a result, we identified PEPTIDYL-tRNA HYDROLASE II (PTH2). In the wild type, elongation growth was suppressed by hypergravity, but this did not happen in the pth2 mutant. Lateral growth, dynamics of cortical microtubules, mechanical properties of cell walls, or cell wall thickness were also not affected by hypergravity in the pth2 mutant. In other words, the pth2 mutant did not show any significant hypergravity responses. However, the gravitropic curvature of hypocotyls of the pth2 mutant was almost equal to that of the wild type, indicating that the PTH2 gene is not required for gravitropism. It is suggested by these results that PTH2 is responsible for the critical processes of gravity resistance in Arabidopsis hypocotyls.

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2

Soga, Kouichi, Kazuyuki Wakabayashi, Seiichiro Kamisaka, and Takayuki Hoson. "Mechanoreceptors rather than sedimentable amyloplasts perceive the gravity signal in hypergravity-induced inhibition of root growth in azuki bean." Functional Plant Biology 32, no. 2 (2005): 175. http://dx.doi.org/10.1071/fp04145.

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Elongation of primary roots of azuki bean (Vigna angularis Ohwi et Ohashi) was suppressed under hypergravity conditions produced by centrifugation, such that the growth rate decreased in proportion to the logarithm of the magnitude of the gravity. The removal of the root cap did not influence the hypergravity-induced inhibition of root growth, although it completely inhibited the gravitropic root curvature. Lanthanum and gadolinium, blockers of mechanoreceptors, nullified the growth-inhibitory effect of hypergravity. These results suggest that the gravity signal for the hypergravity-induced inhibition of root growth is perceived independently from that of gravitropism, which involves amyloplasts as statoliths. Horizontal and basipetal hypergravity suppressed root growth as did acropetal hypergravity, all of which were nullified by the presence of lanthanum or gadolinium. These findings suggest that mechanoreceptors on the plasma membrane perceive the gravity signal independently of the direction of the stimuli and roots may utilise it to regulate their growth rate.

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3

Park, J., M. L. Salmi, W. W. A. Wan Salim, A. Rademacher, B. Wickizer, A. Schooley, J. Benton, et al. "An autonomous lab on a chip for space flight calibration of gravity-induced transcellular calcium polarization in single-cell fern spores." Lab on a Chip 17, no. 6 (2017): 1095–103. http://dx.doi.org/10.1039/c6lc01370h.

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4

Musgrave, M. E., A. Kuang, J. Allen, J. Blasiak, and J. J. W. A. van Loon. "Brassica rapa L. seed development in hypergravity." Seed Science Research 19, no. 2 (June 2009): 63–72. http://dx.doi.org/10.1017/s0960258509303360.

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AbstractPrevious experiments had shown that microgravity adversely affected seed development in Brassica rapa L. We tested the hypothesis that gravity controls seed development via modulation of gases around the developing seeds, by studying how hypergravity affects the silique microenvironment and seed development. Using an in vitro silique maturation system, we sampled internal silique gases for 16 d late in the seed maturation sequence at 4 g or 1 g. The carbon dioxide level was significantly higher inside the 4-g siliques, and the immature seeds became heavier than those maturing at 1 g. Pollination and early embryo development were also studied by growing whole plants at 2 g or 4 g for 16 d inside chambers mounted on a large-diameter centrifuge. Each day the rotor was briefly stopped to permit manual pollination of flowers, thereby producing cohorts of same-aged siliques for comparison with stationary control material. The loss of starch and soluble carbohydrates during seed development was accelerated in hypergravity, with seeds developing at 4 g more advanced by 2 d than those at 1 g. Seeds produced at 4 g contained more lipid than those at 1 g. Taken together, these results indicate that hypergravity enhances gas availability to the developing embryos. Gravity's role in seed development is of importance to the space programme because of the plan to use plants for food production and habitat regeneration in extraterrestrial settings. These results are significant because they underscore the tight co-regulation of Brassica seed development and the atmosphere maintained inside the siliques.

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5

Souza, Tiago Alves Jorge de, Greice Lubini, Andrea Carla Quiapim, and Tiago Campos Pereira. "Nicotiana benthamiana seeds tolerate hyperaccelerations up to 400,000 x g." Research, Society and Development 10, no. 8 (July 12, 2021): e27510817323. http://dx.doi.org/10.33448/rsd-v10i8.17323.

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Exposure to hypergravity can alter the viability, morphology, development and behavior of living beings. Thus, the analysis of these factors is essential when considering life on supermassive planets, as well as in 'ballistic panspermia' scenarios related to the ejection of rocks from the surface of a planet, which could serve as transfer vehicles to spread the life between planets within a solar system. Studies analyzing the effects of hypergravity regimes are abundant in the literature, however, only a few researches carried out experiments using conditions of the order of 105 x g. In addition, the only plant species tested so far, as an entire structure instead of detached parts, exposed to gravity stress of this order of magnitude in its entirety was Oryza sativa, whose seeds were able to germinate after being exposed to 450,000 x g. Recently, our research group demonstrated that some free-living nematode species can support 400,000 x g. In the present study, we report that seeds of the plant model Nicotiana benthamiana exposed to 400,000 x g for 1h are able to germinate into fully normal young seedlings, with no apparent morphological alterations. Since N. benthamiana is used in laboratories worldwide and an easy to cultivate plant model, theoretical and experimental models of lithopanspermia and life in supermassive planets may benefit from it.

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6

Musgrave, Mary E., Anxiu Kuang, Joan Allen, and Jack J. W. A. van Loon. "Hypergravity prevents seed production in Arabidopsis by disrupting pollen tube growth." Planta 230, no. 5 (August 1, 2009): 863–70. http://dx.doi.org/10.1007/s00425-009-0992-5.

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7

kasahara, Hirokazu, Masahide Shiwa, Yuichi Takeuchi, and Mitsuhiro Yamada. "Effects of hypergravity on the elongation growth in radish and cucumber hypocotyls." Journal of Plant Research 108, no. 1 (March 1995): 59–64. http://dx.doi.org/10.1007/bf02344306.

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8

Fitzelle, Karli J., and John Z. Kiss. "Restoration of gravitropic sensitivity in starch‐deficient mutants of Arabidopsis by hypergravity." Journal of Experimental Botany 52, no. 355 (February 2001): 265–75. http://dx.doi.org/10.1093/jexbot/52.355.265.

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9

Hoson, T., K. Nishitani, K. Miyamoto, J. Ueda, S. Kamisaka, R. Yamamoto, and Y. Masuda. "Effects of hypergravity on growth and cell wall properties of cress hypocotyls." Journal of Experimental Botany 47, no. 4 (1996): 513–17. http://dx.doi.org/10.1093/jxb/47.4.513.

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10

Takemura, Kaori, Hiroyuki Kamachi, Atsushi Kume, Tomomichi Fujita, Ichirou Karahara, and Yuko T. Hanba. "A hypergravity environment increases chloroplast size, photosynthesis, and plant growth in the moss Physcomitrella patens." Journal of Plant Research 130, no. 1 (November 28, 2016): 181–92. http://dx.doi.org/10.1007/s10265-016-0879-z.

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11

Soga, Kouichi, Kazuyuki Wakabayashi, Seiichiro Kamisaka, and Takayuki Hoson. "Hypergravity induces reorientation of cortical microtubules and modifies growth anisotropy in azuki bean epicotyls." Planta 224, no. 6 (June 10, 2006): 1485–94. http://dx.doi.org/10.1007/s00425-006-0319-8.

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12

Hodick, D., and A. Sievers. "Hypergravity can reduce but not enhance the gravitropic response ofChara globularis protonemata." Protoplasma 204, no. 3-4 (September 1998): 145–54. http://dx.doi.org/10.1007/bf01280321.

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13

Takemura, Kaori, Rina Watanabe, Ryuji Kameishi, Naoya Sakaguchi, Hiroyuki Kamachi, Atsushi Kume, Ichirou Karahara, Yuko T. Hanba, and Tomomichi Fujita. "Hypergravity of 10g Changes Plant Growth, Anatomy, Chloroplast Size, and Photosynthesis in the Moss Physcomitrella patens." Microgravity Science and Technology 29, no. 6 (October 27, 2017): 467–73. http://dx.doi.org/10.1007/s12217-017-9565-6.

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14

Takemura, Kaori, Hiroyuki Kamachi, Atsushi Kume, Tomomichi Fujita, Ichirou Karahara, and Yuko T. Hanba. "Correction to: A hypergravity environment increases chloroplast size, photosynthesis, and plant growth in the moss Physcomitrella patens." Journal of Plant Research 131, no. 5 (July 18, 2018): 887. http://dx.doi.org/10.1007/s10265-018-1054-5.

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15

Tamaoki, Daisuke, Ichirou Karahara, Lukas Schreiber, Tatsuya Wakasugi, Kyoji Yamada, and Seiichiro Kamisaka. "Effects of hypergravity conditions on elongation growth and lignin formation in the inflorescence stem of Arabidopsis thaliana." Journal of Plant Research 119, no. 2 (November 19, 2005): 79–84. http://dx.doi.org/10.1007/s10265-005-0243-1.

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16

Tamaoki, D., I. Karahara, T. Nishiuchi, T. Wakasugi, K. Yamada, and S. Kamisaka. "Effects of hypergravity stimulus on global gene expression during reproductive growth inArabidopsis." Plant Biology 16 (December 23, 2013): 179–86. http://dx.doi.org/10.1111/plb.12124.

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17

Tamaoki, D., I. Karahara, T. Nishiuchi, S. De Oliveira, L. Schreiber, T. Wakasugi, K. Yamada, K. Yamaguchi, and S. Kamisaka. "Transcriptome profiling in Arabidopsis inflorescence stems grown under hypergravity in terms of cell walls and plant hormones." Advances in Space Research 44, no. 2 (July 2009): 245–53. http://dx.doi.org/10.1016/j.asr.2009.03.016.

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18

Tamaoki, D., I. Karahara, T. Nishiuchi, T. Wakasugi, K. Yamada, and S. Kamisaka. "Involvement of auxin dynamics in hypergravity-induced promotion of lignin-related gene expression in Arabidopsis inflorescence stems." Journal of Experimental Botany 62, no. 15 (August 12, 2011): 5463–69. http://dx.doi.org/10.1093/jxb/err224.

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19

Schmidt, Werner, and Paul Galland. "Optospectroscopic Detection of Primary Reactions Associated with the Graviperception of Phycomyces. Effects of Micro- and Hypergravity." Plant Physiology 135, no. 1 (April 30, 2004): 183–92. http://dx.doi.org/10.1104/pp.103.033282.

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20

Soga, Kouichi, Keita Harada, Kazuyuki Wakabayashi, Takayuki Hoson, and Seiichiro Kamisaka. "Increased Molecular Mass of Hemicellulosic Polysaccharides is Involved in Growth Inhibition of Maize Coleoptiles and Mesocotyls under Hypergravity Conditions." Journal of Plant Research 112, no. 3 (September 1999): 273–78. http://dx.doi.org/10.1007/pl00013881.

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21

Manzano, Ana I., Raúl Herranz, Jack J. W. A. van Loon, and F. Javier Medina. "A Hypergravity Environment Induced by Centrifugation Alters Plant Cell Proliferation and Growth in an Opposite Way to Microgravity." Microgravity Science and Technology 24, no. 6 (June 3, 2012): 373–81. http://dx.doi.org/10.1007/s12217-012-9301-1.

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22

Kasahara, Hirokazu, Kazumi Yanagiya, Yuichi Takeuchi, Masamichi Yamashita, and Mitsuhiro Yamada. "Effects of hypergravity on the elongation and morphology of protonemata of Adiantum capillus-veneris." Physiologia Plantarum 93, no. 2 (February 1995): 352–56. http://dx.doi.org/10.1111/j.1399-3054.1995.tb02239.x.

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23

NAKABAYASHI, IZUMI, ICHIROU KARAHARA, DAISUKE TAMAOKI, KYOJIRO MASUDA, TATSUYA WAKASUGI, KYOJI YAMADA, KOUICHI SOGA, TAKAYUKI HOSON, and SEIICHIRO KAMISAKA. "Hypergravity Stimulus Enhances Primary Xylem Development and Decreases Mechanical Properties of Secondary Cell Walls in Inflorescence Stems of Arabidopsis thaliana." Annals of Botany 97, no. 6 (March 14, 2006): 1083–90. http://dx.doi.org/10.1093/aob/mcl055.

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24

Scherer, G. F. E. "Halotolerance is enhanced in carrot callus by sensing hypergravity: influence of calcium modulators and cytochalasin D." Protoplasma 229, no. 2-4 (December 2006): 149–54. http://dx.doi.org/10.1007/s00709-006-0201-3.

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25

Wakabayashi, Kazuyuki, Saho Nakano, Kouichi Soga, and Takayuki Hoson. "Cell wall-bound peroxidase activity and lignin formation in azuki bean epicotyls grown under hypergravity conditions." Journal of Plant Physiology 166, no. 9 (June 2009): 947–54. http://dx.doi.org/10.1016/j.jplph.2008.12.006.

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26

Wakabayashi, Kazuyuki, Seiichiro Kamisaka, Takayuki Hoson, and Kouichi Soga. "Graviperception in growth inhibition of plant shoots under hypergravity conditions produced by centrifugation is independent of that in gravitropism and may involve mechanoreceptors." Planta 218, no. 6 (April 1, 2004): 1054–61. http://dx.doi.org/10.1007/s00425-003-1187-0.

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27

Wakabayashi, Kazuyuki, Kouichi Soga, Seiichiro Kamisaka, and Takayuki Hoson. "Increase in the level of arabinoxylan-hydroxycinnamate network in cell walls of wheat coleoptiles grown under continuous hypergravity conditions." Physiologia Plantarum 125, no. 1 (September 2005): 127–34. http://dx.doi.org/10.1111/j.1399-3054.2005.00544.x.

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28

Clark, Torin K., Michael C. Newman, Charles M. Oman, Daniel M. Merfeld, and Laurence R. Young. "Human perceptual overestimation of whole body roll tilt in hypergravity." Journal of Neurophysiology 113, no. 7 (April 2015): 2062–77. http://dx.doi.org/10.1152/jn.00095.2014.

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Hypergravity provides a unique environment to study human perception of orientation. We utilized a long-radius centrifuge to study perception of both static and dynamic whole body roll tilt in hypergravity, across a range of angles, frequencies, and net gravito-inertial levels (referred to as G levels). While studies of static tilt perception in hypergravity have been published, this is the first to measure dynamic tilt perception (i.e., with time-varying canal stimulation) in hypergravity using a continuous matching task. In complete darkness, subjects reported their orientation perception using a haptic task, whereby they attempted to align a hand-held bar with their perceived horizontal. Static roll tilt was overestimated in hypergravity, with more overestimation at larger angles and higher G levels, across the conditions tested (overestimated by ∼35% per additional G level, P < 0.001). As our primary contribution, we show that dynamic roll tilt was also consistently overestimated in hypergravity ( P < 0.001) at all angles and frequencies tested, again with more overestimation at higher G levels. The overestimation was similar to that for static tilts at low angular velocities but decreased at higher angular velocities ( P = 0.006), consistent with semicircular canal sensory integration. To match our findings, we propose a modification to a previous Observer-type canal-otolith interaction model. Specifically, our data were better modeled by including the hypothesis that the central nervous system treats otolith stimulation in the utricular plane differently than stimulation out of the utricular plane. This modified model was able to simulate quantitatively both the static and the dynamic roll tilt overestimation in hypergravity measured experimentally.

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29

Nooij, Suzanne A. E., Jelte E. Bos, and Eric L. Groen. "Orientation of Listing's plane after hypergravity in humans." Journal of Vestibular Research 18, no. 2-3 (December 26, 2008): 97–105. http://dx.doi.org/10.3233/ves-2008-182-303.

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Adaptation to a novel gravitational state involves adaptation of vestibular mediated responses, in particular those mediated by the otolith organs. The present paper investigates whether the orientation of Listing's plane, which is under control of otolith signals, is affected by sustained exposure to hypergravity. Subjects were exposed to four G-loads differing in duration (45 or 90 min) and magnitude (2 or 3G). During centrifugation subjects were in a supine position, directing the gravito-inertial acceleration along the naso-occipetal axis. We determined the orientation of Listing's plane before and after each centrifuge run, with the head erect and tilted in pitch. Head tilt in pitch induced a counter-pitch of Listing's plane, which was found to be less pronounced after centrifugation. In addition, exposure to 3G for 90~min induced a small backward tilt of Listing's plane compared to the pretest orientation (head erect). In order to explain these results a hypothesis is discussed, proposing that the orientation of Listing's plane in the head is governed by a head fixed orientation vector that is modulated by the direction of gravity relative to the head. Sustained centrifugation is proposed to decrease this gravitational modulation, leading to the effects observed. This could reflect a shift towards a more body centered frame of reference.

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30

Li, Gen, and Xiande Fang. "Numerical Simulation on the Boiling Flow Patterns of Al2O3-Water Nanofluid in Micro/Minichannel under Different Hypergravity Levels and Directions." International Journal of Aerospace Engineering 2021 (December 17, 2021): 1–12. http://dx.doi.org/10.1155/2021/4802182.

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Due to the influence of hypergravity that has a significant impact on the performance of heat exchanger in aircraft, which is crucial for electronic equipment on the plane and life safeties of pilots and passengers, a numerical study is conducted using Fluent 20R2 software to investigate boiling flow patterns under different gravity levels and directions. In this study, the thermophysical properties of nanofluids are analyzed, and select the most suitable theoretical model of thermal conductivity, viscosity, and surface tension for present simulations. Choose the grid structure of 122,116 after independence check for grid. The VOF approach is employed for present simulation, and the standard κ − ε turbulence model with nonequilibrium wall function is used. The UDFs for mass and energy source terms and thermophysical properties of nanofluid are developed for calculating the HTC of nanofluid. There are three different gravity directions with gravity levels from 1 g to 9 g. The results show that the flow pattern becomes the stratified flow with the gravity levels increasing when the hypergravity direction is perpendicular to the flow direction, and the HTCs decrease with the increment of gravity levels. The vapor-phase transform to circular when the hypergravity direction is the same as the flow direction, and the HTCs of the second half of the tube are decreasing with the increasing gravity levels. On the contrary, the vapor phase is elongated when the hypergravity direction is opposite to the flow direction, and the HTCs show the enhanced tendency.

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31

Crevecoeur, F., J. McIntyre, J. L. Thonnard, and P. Lefèvre. "Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements." Journal of Neurophysiology 112, no. 2 (July 15, 2014): 384–92. http://dx.doi.org/10.1152/jn.00061.2014.

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Moving requires handling gravitational and inertial constraints pulling on our body and on the objects that we manipulate. Although previous work emphasized that the brain uses internal models of each type of mechanical load, little is known about their interaction during motor planning and execution. In this report, we examine visually guided reaching movements in the horizontal plane performed by naive participants exposed to changes in gravity during parabolic flight. This approach allowed us to isolate the effect of gravity because the environmental dynamics along the horizontal axis remained unchanged. We show that gravity has a direct effect on movement kinematics, with faster movements observed after transitions from normal gravity to hypergravity (1.8g), followed by significant movement slowing after the transition from hypergravity to zero gravity. We recorded finger forces applied on an object held in precision grip and found that the coupling between grip force and inertial loads displayed a similar effect, with an increase in grip force modulation gain under hypergravity followed by a reduction of modulation gain after entering the zero-gravity environment. We present a computational model to illustrate that these effects are compatible with the hypothesis that participants partially attribute changes in weight to changes in mass and scale incorrectly their motor commands with changes in gravity. These results highlight a rather direct internal mapping between the force generated during stationary holding against gravity and the estimation of inertial loads that limb and hand motor commands must overcome.

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32

Jenkin, Michael, James Zacher, Richard Dyde, Laurence Harris, and Heather Jenkin. "Perceptual Upright: The Relative Effectiveness of Dynamic and Static Images Under Different Gravity States." Seeing and Perceiving 24, no. 1 (2011): 53–64. http://dx.doi.org/10.1163/187847511x555292.

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AbstractThe perceived direction of up depends on both gravity and visual cues to orientation. Static visual cues to orientation have been shown to be less effective in influencing the perception of upright (PU) under microgravity conditions than they are on earth (Dyde et al., 2009). Here we introduce dynamic orientation cues into the visual background to ascertain whether they might increase the effectiveness of visual cues in defining the PU under different gravity conditions. Brief periods of microgravity and hypergravity were created using parabolic flight. Observers viewed a polarized, natural scene presented at various orientations on a laptop viewed through a hood which occluded all other visual cues. The visual background was either an animated video clip in which actors moved along the visual ground plane or an individual static frame taken from the same clip. We measured the perceptual upright using the oriented character recognition test (OCHART). Dynamic visual cues significantly enhance the effectiveness of vision in determining the perceptual upright under normal gravity conditions. Strong trends were found for dynamic visual cues to produce an increase in the visual effect under both microgravity and hypergravity conditions.

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33

Frerichs, Inéz, Taras Dudykevych, José Hinz, Marc Bodenstein, Günter Hahn, and Gerhard Hellige. "Gravity effects on regional lung ventilation determined by functional EIT during parabolic flights." Journal of Applied Physiology 91, no. 1 (July 1, 2001): 39–50. http://dx.doi.org/10.1152/jappl.2001.91.1.39.

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Gravity-dependent changes of regional lung function were studied during normogravity, hypergravity, and microgravity induced by parabolic flights. Seven healthy subjects were followed in the right lateral and supine postures during tidal breathing, forced vital capacity, and slow expiratory vital capacity maneuvers. Regional 1) lung ventilation, 2) lung volumes, and 3) lung emptying behavior were studied in a transverse thoracic plane by functional electrical impedance tomography (EIT). The results showed gravity-dependent changes of regional lung ventilation parameters. A significant effect of gravity on regional functional residual capacity with a rapid lung volume redistribution during the gravity transition phases was established. The most homogeneous functional residual capacity distribution was found at microgravity. During vital capacity and forced vital capacity in the right lateral posture, the decrease in lung volume on expiration was larger in the right lung region at all gravity phases. During tidal breathing, the differences in ventilation magnitudes between the right and left lung regions were not significant in either posture or gravity phase. A significant nonlinearity of lung emptying was determined at normogravity and hypergravity. The pattern of lung emptying was homogeneous during microgravity.

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34

de Sousa, Nídia, Gustavo Rodriguez-Esteban, Ivan Colagè, Paolo D’Ambrosio, Jack van Loon, Emili Saló, Teresa Adell, and Gennaro Auletta. "Transcriptomic Analysis of Planarians under Simulated Microgravity or 8 g Demonstrates That Alteration of Gravity Induces Genomic and Cellular Alterations That Could Facilitate Tumoral Transformation." International Journal of Molecular Sciences 20, no. 3 (February 8, 2019): 720. http://dx.doi.org/10.3390/ijms20030720.

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The possibility of humans to live outside of Earth on another planet has attracted the attention of numerous scientists around the world. One of the greatest difficulties is that humans cannot live in an extra-Earth environment without proper equipment. In addition, the consequences of chronic gravity alterations in human body are not known. Here, we used planarians as a model system to test how gravity fluctuations could affect complex organisms. Planarians are an ideal system, since they can regenerate any missing part and they are continuously renewing their tissues. We performed a transcriptomic analysis of animals submitted to simulated microgravity (Random Positioning Machine, RPM) (s-µg) and hypergravity (8 g), and we observed that the transcriptional levels of several genes are affected. Surprisingly, we found the major differences in the s-µg group. The results obtained in the transcriptomic analysis were validated, demonstrating that our transcriptomic data is reliable. We also found that, in a sensitive environment, as under Hippo signaling silencing, gravity fluctuations potentiate the increase in cell proliferation. Our data revealed that changes in gravity severely affect genetic transcription and that these alterations potentiate molecular disorders that could promote the development of multiple diseases such as cancer.

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35

Gaveau, Jérémie, Christos Paizis, Bastien Berret, Thierry Pozzo, and Charalambos Papaxanthis. "Sensorimotor adaptation of point-to-point arm movements after spaceflight: the role of internal representation of gravity force in trajectory planning." Journal of Neurophysiology 106, no. 2 (August 2011): 620–29. http://dx.doi.org/10.1152/jn.00081.2011.

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After an exposure to weightlessness, the central nervous system operates under new dynamic and sensory contexts. To find optimal solutions for rapid adaptation, cosmonauts have to decide whether parameters from the world or their body have changed and to estimate their properties. Here, we investigated sensorimotor adaptation after a spaceflight of 10 days. Five cosmonauts performed forward point-to-point arm movements in the sagittal plane 40 days before and 24 and 72 h after the spaceflight. We found that, whereas the shape of hand velocity profiles remained unaffected after the spaceflight, hand path curvature significantly increased 1 day after landing and returned to the preflight level on the third day. Control experiments, carried out by 10 subjects under normal gravity conditions, showed that loading the arm with varying loads (from 0.3 to 1.350 kg) did not affect path curvature. Therefore, changes in path curvature after spaceflight cannot be the outcome of a control process based on the subjective feeling that arm inertia was increased. By performing optimal control simulations, we found that arm kinematics after exposure to microgravity corresponded to a planning process that overestimated the gravity level and optimized movements in a hypergravity environment (∼1.4 g). With time and practice, the sensorimotor system was recalibrated to Earth's gravity conditions, and cosmonauts progressively generated accurate estimations of the body state, gravity level, and sensory consequences of the motor commands (72 h). These observations provide novel insights into how the central nervous system evaluates body (inertia) and environmental (gravity) states during sensorimotor adaptation of point-to-point arm movements after an exposure to weightlessness.

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36

Taube, Jeffrey S., Robert W. Stackman, Jeffrey L. Calton, and Charles M. Oman. "Rat Head Direction Cell Responses in Zero-Gravity Parabolic Flight." Journal of Neurophysiology 92, no. 5 (November 2004): 2887–997. http://dx.doi.org/10.1152/jn.00887.2003.

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Astronauts working in zero-gravity (0-G) often experience visual reorientation illusions (VRIs). For example, when floating upside down, they commonly misperceive the spacecraft floor as a ceiling and have a reversed sense of direction. Previous studies have identified a population of neurons in the rat's brain that discharge as a function of the rat's head direction (HD) in a gravitationally horizontal plane and is dependent on an intact vestibular system. Our goal was to characterize HD cell discharge under conditions of acute weightlessness. Seven HD cells in the anterior dorsal thalamus were monitored from rats aboard an aircraft in 0-G parabolic flight. Unrestrained rats locomoted in a clear plexiglas rectangular chamber that had wire mesh covering the floor, ceiling, and one wall. The chamber and surrounding visual environment were relatively up-down symmetrical. Each HD cell was recorded across forty 20-s episodes of 0-G. All HD cells maintained a significant direction-specific discharge when the rat was on the chamber floor during the 0-G and also during the hypergravity pull-out periods. Three of five cells also showed direction-specific responses on the wall in 1-G. In contrast, direction-specific discharge was usually not maintained when the rat locomoted on the vertical wall or ceiling in 0-G. The loss of direction-specific firing was accompanied by an overall increase in background firing. However, while the rat was on the ceiling, some cells showed occasional bursts of firing when the rat's head was oriented in directions that were flipped relative to the long axis of symmetry of the chamber compared with the cell's preferred firing direction on the floor. This finding is consistent with what might be expected if the rat had experienced a VRI. These responses indicate that rats maintain a normal allocentric frame of reference in 0-G and 1-G when on the floor, but may lose their sense of directional heading when placed on a wall or ceiling during acute exposures to 0-G.

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Swamy, Basavalingayya K., Ravikumar Hosamani, Malarvizhi Sathasivam, S. S. Chandrashekhar, Uday G. Reddy, and Narayan Moger. "Novel hypergravity treatment enhances root phenotype and positively influences physio-biochemical parameters in bread wheat (Triticum aestivum L.)." Scientific Reports 11, no. 1 (July 27, 2021). http://dx.doi.org/10.1038/s41598-021-94771-8.

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AbstractHypergravity—an evolutionarily novel environment has been exploited to comprehend the response of living organisms including plants in the context of extra-terrestrial applications. Recently, researchers have shown that hypergravity induces desired phenotypic variability in seedlings. In the present study, we tested the utility of hypergravity as a novel tool in inducing reliable phenotype/s for potential terrestrial crop improvement applications. To investigate, bread wheat seeds (UAS-375 genotype) were subjected to hypergravity treatment (10×g for 12, and 24 h), and evaluated for seedling vigor and plant growth parameters in both laboratory and greenhouse conditions. It was also attempted to elucidate the associated biochemical and hormonal changes at different stages of vegetative growth. Resultant data revealed that hypergravity treatment (10×g for 12 h) significantly enhanced root length, root volume, and root biomass in response to hypergravity. The robust seedling growth phenotype may be attributed to increased alpha-amylase and TDH enzyme activities observed in seeds treated with hypergravity. Elevated total chlorophyll content and Rubisco (55 kDa) protein expression across different stages of vegetative growth in response to hypergravity may impart physiological benefits to wheat growth. Further, hypergravity elicited robust endogenous phytohormones dynamics in root signifying altered phenotype/s. Collectively, this study for the first time describes the utility of hypergravity as a novel tool in inducing reliable root phenotype that could be potentially exploited for improving wheat varieties for better water usage management.

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Hosamani, Ravikumar, Basavalingayya K. Swamy, Ajwal Dsouza, and Malarvizhi Sathasivam. "Plant responses to hypergravity: a comprehensive review." Planta 257, no. 1 (December 19, 2022). http://dx.doi.org/10.1007/s00425-022-04051-6.

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Soga, Kouichi, Kazuyuki Wakabayashi, Seiichiro Kamisaka, and Takayuki Hoson. "Effects of hypergravity on expression of XTH genes in azuki bean epicotyls." Physiologia Plantarum, June 12, 2007, 070612062620003—??? http://dx.doi.org/10.1111/j.1399-3054.2007.00949.x.

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Kume, Atsushi, Hiroyuki Kamachi, Yusuke Onoda, Yuko T. Hanba, Yuji Hiwatashi, Ichirou Karahara, and Tomomichi Fujita. "How plants grow under gravity conditions besides 1 g: perspectives from hypergravity and space experiments that employ bryophytes as a model organism." Plant Molecular Biology, April 14, 2021. http://dx.doi.org/10.1007/s11103-021-01146-8.

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