Circadian Rhythm in 15O-Labeled Water Uptake Manner of a Soybean Plant by PETIS(Position Emitting Tracer Imaging System).

Abstract

We present a circadian rhythm of water uptake manner in a soybean plant through realtime imaging of water, labeled with 150. Nitrogen gas was irradiated with deuterons accelerated by a cyclotron at Hamamatsu Photonics Co. to produce 150-labeled water. Then the 150-labeled water was supplied to a soybean plant from the root and the realtime water uptake amount was measured for 20 min by Positron Emitting Tracer Imaging System (PETIS). All the targeting positions for the measurements were stems, two points at an internode between root and the first leaves, between the first leaves and the first trifoliates and between the first trifoliates and the second trifoliates. The water uptake amount was gradually increased and showed its maximum at around 13:00, especially at the basal part of the stem. Then the water uptake activity was gradually decreased until 17:00. The water amount taken up by a plant at 13:00 was about 40% higher than that at 17:00.

A circadian and an ultradian rhythm are both evident in root growth of rice

“…The circadian rhythm, an endogenous rhythm observed in plants, has been studied extensively in relation to plant shoot growth (Walter et al, 2009). Daily rhythmic patterns for plant root growth parameters have also been found with respect to various physiological phenomena such as nitrate uptake (Pearson and Steer, 1977), root respiration (Hansen, 1980), xylem sap exudation (Vaadia, 1960), hydraulic conductivity, root pressure (Henzler et al, 1999), water uptake (Nakanishi et al, 2001), and mucilage exudation (Iijima et al, 2003c). Recently, a diurnal growth pattern of root elongation was reported in Arabidopsis thaliana , although the endogenous rhythmicity itself was not analyzed.…”

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“…However, the lower picture showed clear difference of the water distribution between heartwood and sapwood parts. Water image of the Japanese cypress showed high amount of water in only outer part of the wood and small amount of water was distributed along the annual ring in inner part Water movement using RI: water movement [28][29][30][31][32][33][34][35] The first trial to analyze water absorption manner was studied using the cowpea plant supplied with 18 F (half-life: 110 min) containing water, which was produced by irradiation of water with He ? beam.…”

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“…While this spatial resolution is four times finer than that of the Duke prototype PET device, the imaging area is reduced by about a factor of 8. Since this original application, the PETIS device has been used to visualize translocation of 11 C-labeled methionine in barley (Nakanishi et al, 1999), 13 N-labeled nitrates in soybean plants (Ohtake et al, 2001), 13 N-labeled ammonium in rice (Kiyomiya et al, 2001b), and 15 O-labeled water in soybean plants (Nakanishi et al, 2001a). The primary limitation of the original PETIS was the small FOV.…”