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Light‐induced Starch Degradation in Non‐dormant Turions of Spirodela polyrhiza ¶
Author(s) -
Appenroth KlausJ.,
Gabrys Halina
Publication year - 2001
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2001)0730077lisdin2.0.co2
Subject(s) - phytochrome , starch , germination , botany , far red , biology , degradation (telecommunications) , biophysics , red light , food science , telecommunications , computer science
Continuous red light controls starch degradation in turions of Spirodela polyrhiza [Dölger, K., U. K. Tirlapur and K.‐J. Appenroth [1997] Photochem. Photobiol. 66, 126–127 (1997)]. This light could be replaced by repeated red light pulses with the reciprocity law fulfilled over a large range of fluence rates. The effect of red light pulses repeated every 24 or 12 h for 6 days was reversible by subsequent far‐red light pulses. In contrast, hourly applied red pulses were irreversible by far‐red light. This discrepancy was explained by showing the starch degradation activity of far‐red pulses themselves. The investigated process was categorized as a phytochrome low fluence response with an unusual property: requirement of light treatment for several days. A partial fulfillment of this requirement was obtained with a red pulse followed by a dark period and a 24 h continuous irradiation. These results suggest the existence of two separate steps in the process of starch degradation in turions: formation of a sprout (=sink) during the pulse‐induced germination, and starch degradation in the storage tissue (=source) induced by the second light treatment.