Phosphatidylinositol metabolism in low temperature-affected winter oilseed rape leaves [cold acclimation]
1994
Smolenska-Sym, G. | Kacperska, A.
The aim of the present experiments was to find out whether low temperature may put into operation the phospholipase C-inositolphospholipid signaling cascade in tissues of chilling-tolerant plants. Therefore, the effects of a short and a rapid exposure of non-acclimated (NA) and cold-acclimated (CA) winter oilseed rape (Brassica napus L. var. oleifera L. cv. Jantar) leaves to chilling (0 deg C) or freezing (-5 deg C, -7 deg C) temperatures on the inositolphospholipid (PI, PIP and PIP2) contents and [2-3H]-inositol incorporation into phosphoinositides and inositol phosphates (IP3, IP2, and IP) were studied. LiCl (50 mM) was used to arrest inositol phosphate hydrolysis on the IP level. Cold acclimation resulted in increased contents of PI and PIP2 in the leaves. Rapid exposure of NA leaves to 0 deg C. and CA leaves to -7 deg C. (temperature of ice nucleation in the tissue) increased the amount of radioactivity in inositol phosphates and decreased the radioactivity in PIP2 and PIP. The data indicate that low temperature induced phospholiphase C activity in winter rape leaves, the effectiveness of the treatment being dependent on the state of plant acclimation to cold. Mechanisms engaged and some biological implications of the responses observed for cold acclimation of plants are discussed
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