by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC], [Springfield, Va .
Written in English
|Statement||principal investigator: David G. Heathcote.|
|Series||NASA contractor report -- NASA-CR 192157., NASA contractor report -- NASA CR-192157.|
|Contributions||United States. National Aeronautics and Space Administration.|
|The Physical Object|
The investigation was designed to provide data on the responses of wheat seedlings to various blue-light stimuli given while the plants were exposed to orbital microgravity conditions. Before the flight, a number of hypotheses were established which were to be tested by . The phototropic dose-response relationship has been determined for Triticum aestivum cv. Broom coleoptiles growing on a purpose-built clinostat apparatus providing gravity compensation by rotation. The 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 experiments showed that the shortest gravitropic curvature corresponded to 30° initial angle of gravistimulation (IAG).Author: N.V. Zyablova, Yu.A. Berkovich, A.N. Erokhin, Skripnikov. The study was conducted during Rabi season of at the Wheat Research Centre (WRC), Bangladesh Agricultural Research Institute (BARI), Dinajpur. Thirty wheat genotypes including local control BARI Gom 26 were evaluated in split-split plot design having two replications with irrigation in the main plot, seeding depth in a sub-plot and genotype was in sub-sub-plot.
Although the second positive phototropic response has often been referred to as the base response, photoreception for it is shown to occur mainly in the apical 3 mm of the coleoptile. The Bunsen-Roscoe reciprocity law, so typical of first positive phototropism, does not apply to the second positive responses, and the amount of curvature. Coleoptile Length of Wheat Varieties Jennifer Pumpa, Peter Martin, Frank McRae and Neil Coombes Coleoptile length is an important characteristic to consider when planting a wheat crop, especially in drier seasons when sowing deep to reach soil moisture. The coleoptile is the pointed protective sheath that encases the emerging shoot as it. Investigation of natural auxins and growth inhibitors markedly increases the response of oat coleoptile sections to lAA, though Schneider () reported that first internodes were almost insensitive to sucrose. Search Results for Coleoptile Stock Photos and Images (). tropic response from the lower and non-illuminated parts, the magnitude of coleoptile curvature was de-termined bymeasuring only that part of the coleoptile more than 2mmabovethe node. Plants in whichthe node showed obvious curvature were discarded. Victory oats (Avena sativa L. var. victory) were hulled and soaked in tap water for exactly 2 hours.
The time course of phototropic response to min stimulation was investigated with wild-type and cpt1 coleoptiles (Figure 6B, circles). The fluence rate of blue light used was μmol m −2 s −1. As shown in Figure 6B (circles), wild-type coleoptiles showed a biphasic time course with a . To measure the temporal pattern of wheat coleoptile growth, germinated seeds were grown in the dark for 1 day, and then the coleoptiles were measured and harvested every 6 h in green light. Extraction of cell wall proteins Cell wall proteins in the wheat coleoptiles were extracted according to the method of McQueen-Mason et al. (). Fig 1. Straightening movement of a wheat coleoptile, in the standard reading direction. The white line accounts for 10 mm. The time between each frame is minutes. The orange points on the coleoptile are the fluorescent markers used for the measurement . A time-lapse sequence of such a spatio-temporal response is shown in Fig. 2a for a Triticum aestivum wheat coleoptile grown in the dark under g and initially inclined at θ init = 50°.