Journal
RUSSIAN JOURNAL OF PLANT PHYSIOLOGY
Volume 53, Issue 1, Pages 96-101Publisher
MAIK NAUKA/INTERPERIODICA/SPRINGER
DOI: 10.1134/S1021443706010122
Keywords
Pisum sativum; seeds; accelerated ageing; fractions of seeds differing in quality; aquaporins; water channels; p-chloromercuribenzoate; dithiothreitol; NaF
Categories
Ask authors/readers for more resources
Using the method of room temperature phosphorescence (RTP), we divided air-dry pea (Pisum sativum L.) seeds subjected to accelerated ageing (40 degrees C, 85% relative humidity) into three fractions: (I) high-quality seeds, (II) weakened seeds, and (III) dead seeds. In the process of ageing, seed germinability firstly decreased and then increased due to so-called improved seeds of fraction II, which returned to fraction I as judged from the RTP level; the germinability of these seeds became equal to that of fraction I seeds. Seeds capable of germination (fractions I and II) differed in the rates of imbibition, which depended on plasma membrane permeability (opened or closed water channels) but not on the presence of the seed coat. A low activation energy of seed imbibition in fraction II (less than 5 kcal/mol) indicates that water channels are open. A mercury-containing compound (5 mu M p-chloromercuribenzoate (PCMB) reduced the rate of water uptake by these seeds, and dithiothreitol restored it. A high activation energy of fraction I seed imbibition (more than 12 kcal/mol) corresponded to the water uptake mainly across the lipid bilayer when water channels are closed. PCMB did not affect the rate of fraction I seed imbibition. We supposed that mature air-dry pea seeds had open water channels. During the first stages of fraction I seed imbibition, these channels were closed, limiting water uptake. NaF (100 mu M), an inhibitor of phosphatase, prevented channel closing and accelerated the imbibition of fraction I seeds. It did not affect the imbibition rate of fraction II seeds, indicating their water channels to be opened. However, NaF did not affect the water uptake of improved fraction II seeds as well. It seems likely that their channels were closed during accelerated ageing but otherwise than via dephosphorylation. The results obtained indicate the possibility of water inflow regulation in the weakened seeds via the state of aquaporins, which form water channels in the membranes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available