AbstractThe time course of gravicurvature of 3-day-old wheat (Triticum aestivum L., cv. Apogee) coleoptiles and 7-day-old wheat stems were studied in darkness and under red and red-blue light illumination after declination from the vertical at various angles. The experiments showed that the shortest gravitropic curvature corresponded to 30° initial angle of gravistimulation (IAG). The time course became longer as the IAG increased and with plant age. The effects of unilateral red (660nm) and red-blue light (660nm; 470nm) at photosynthetic photon flux (PPF) of 30μmolm−2s−1 on the curvature of 3-day-old coleoptiles were evaluated. Red light did not produce phototropic bending of wheat coleoptiles in contrast with red-blue light. The analysis of experimental data showed that the curvature in response to a gravitropic stimulus or to combined gravity-light stimuli were not statistically different. Time course of gravitropic curvature were used to determine the acceptable crop rotation rate around the horizontal axis. Approximation of stem bending to a linear dynamic system described by a first-order aperiodic element with a lag allowed the determination of the dependence of the amplitude of apex oscillations on the rate of horizontal rotation under 1-g conditions. The calculated lowest minimal rotation rate (MRR) minimizing the gravitropic effects on wheat was about 1 revolution per hour (rph). Rotating the plant growth chamber (PGC) at a rate of more than MRR eliminated the effect of gravitropic curvature.
The gravitropic and phototropic responses of wheat grown in a space greenhouse prototype with hemispherical planting surface
Advances in Space Research ; 46 , 10 ; 1273-1279
2010-05-31
7 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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