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vol. 7, nr. 1 (2006)
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A fractal scaling law for seed hydration kinetics
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Ewa Maria Miedziejko
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Research Center for Agricultural and Forest Environment, Polish Academy of Sciences, ul. Bukowska 19, 60-809 Poznań |
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vol. 7 (2006), nr. 1,
pp. 141-150
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abstract:
The paper reports results of a study of the water sorption rate, PGSE NMR (Pulsed Field Gradient Spin Echo Nuclear Magnetic Resonace) measurements of water diffusion coefficient and photosensitivity by difference spectroscopy in vivo of tobacco (c.v. Księżnicki) and pea (c.v. Finalle) seeds. The probability of water uptake upon seed hydration and the spin-echo amplitude function of seed water proton, both related to the long-lasting evolution, take the form of power law. These dependencies were used to demonstrate that the random deposition of water molecules into the seeds matrix during hydration process leads to filling up the seed volume with characteristic clusters created by diffusion limited by aggregation (DLA). The hydration process starts with the creation of small clusters at and near macromolecules and finishes along with a big percolation one, spreading throughout the seed. Using the fractal model for hydration process it was shown that the PhyA (phytochrome A) heterodimer was a photoreceptor for water flow regulation, activated by a very low fluence reaction (VLFR).
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keywords:
seeds, sorption half-time, fractal dimension, phytochrome
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original in:
Polish
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