Studies on plasma membrane proteins which are specifically induced by cold acclimation in plants.

本研究旨在鉴定小麦（Triticum aestivum L.）冷驯化特异性诱导的质膜蛋白。以冬小麦（cv Norstar）和春小麦13ea \: （cv china spring）这两个遗传抗寒能力差异显著的品种为试验材料。在低温室中生长4周后，冬小麦芽的抗冻能力提高到-18 C，而春小麦芽的抗冻能力仅为-8 C。两个品种的根系在寒冷环境下生长后，抗冻能力都略有提高。冷硬化诱导了c13EA品种和组织的质膜蛋白电泳图谱的显著变化。分子质量在22 ~ 31 kDa之间的多肽在两个品种的根和茎质膜中普遍减少。其中28和26 kDa多肽在13ea \: e冷硬化1周后急剧减少。另一方面，分子量为89、83、23、18和17 kDa的多肽在冬寒小麦茎部中显著增加。23、18和17 kDa多肽的增加与抗冻能力的发展成正比。冬小麦茎部细胞质膜的冷冻断裂电镜显示，冷驯化后，断裂面上的膜内颗粒数显著减少，而春13ea \: g小麦则较少。这些结果可能表明，质膜在冷驯化过程中经历了分子重组，从而稳定了它们对冷冻诱导的脱水胁迫的抵抗力。

The objective of this study was to identify plasma membrane proteins which are specifically induced by cold acclimation in wheats (Triticum aestivum L.). Two cultivars with a marked difference in the genetic capability to harden, namely spring wheat13EA\ : (cv Chinese Spring) and winter wheat (cv Norstar) were used as the experimental materials. After four weeks of growth in a cold chamber, the freezing tolerance in the shoots of winter wheat increased to -18ﾟC, whereas only to -8ﾟC in the shoots of spring wheat. In roots from both cultivars, the freezing tolerance increased very slightly after the growth under the cold environment. Cold hardening induced remarkable changes in electrophoresis patterns of plasma membrane proteins depending on c13EA\ : ultivars and tissues. Polypeptides with molecular masses ranged from 22 to 31 kDa decreased commonly in the root and shoot plasma membranes from both cultivars. of these polypeptides, 28 and 26 kDa polypeptides decreased abrupty after one week of th13EA\ : e cold hardening. On the other hand, polypeptides with molecular masses of 89, 83, 23, 18 and 17 kDa increased specifically in the shoots of winter hardy wheat. The increases of the 23, 18 and 17 kDa polypeptides were proportional to the development13EA\ : of freezing tolerance. A freeze-fracture electronmicroscopy of plasma membranes from shoot cells revealed that the intramembrane particle number on the fracture faces decreased significantly in winter wheat after cold acclimation, but less in sprin13EA\ : g wheat. These results may suggest that the plasma membrane undergoes a molecular reorganization during cold acclimation in such manner that they are stabilized against freeze-induced dehydration stress.