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vol. 9, nr. 1 (2007)
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A temperature study of water uptake by pea seeds
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Grażyna Plencler
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Department of Physics, Agricultural University, ul. Wojska Polskiego 38/42, 60-637 Poznań
e-mail: gplenz@au.poznan.pl |
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vol. 9 (2007), nr. 1,
pp. 183-190
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abstract:
The process of germination depends on the temperature and accessibility of water and oxygen. It starts with the imbibitive absorption of water leading to an increase in the fresh mass and volume of seeds. The kinetics of water absorption by pea seeds at different temperatures and on wetting with water and water solution of mercury chloride HgCl2 were studied. Mercury chloride, known as the inhibitor of water channels (aquaporins), was used for determination of water transport in the conditions of partial water channels blocking. On the basis of the temperature study of water uptake kinetics the hydration constant and activation energy of hydration were calculated. The activation energy of the hydration in the presence of water and water solution of HgCl2 was found to be higher in lower temperatures (280-290K) and was 42 kJ mol-1 and 44 kJ mol-1, respectively. At higher temperatures (290-300K), the activation energy decreased to 30 kJ mol-1 for the seeds in contact with water solution of HgCl2 and for the seeds in contact with water. The results indicated that the water uptake by pea seeds was markedly temperature-dependent with an intersection point near 293 K. 0.2 mM HgCl2 affected the energy barrier for water transport into the seeds insignificantly.
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keywords:
aquaporins (water channels) pea seeds, activation energy, osmoregulation
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original in:
English
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