Karlson Dale T, Zeng Yan, Stirm Vicki E, Joly Robert J, Ashworth Edward N
Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907-1165, USA.
Plant Cell Physiol. 2003 Jan;44(1):25-34. doi: 10.1093/pcp/pcg006.
A predominant 24-kD dehydrin-like protein was previously found to fluctuate seasonally within red-osier dogwood (Cornus sericea L.) stems. The current study attempted to determine what environmental cues triggered the accumulation of the 24-kD protein and to assess its potential role in winter survival. Controlled photoperiod and field studies confirmed that photoperiod regulates a reduction of stem water content (SWC), freeze-tolerance enhancement and accumulation of the 24-kD protein. Diverse climatic ecotypes, which are known to respond to different critical photoperiods, displayed differential reduction of SWC and accumulation of the 24-kD protein. A time-course study confirmed that prolonged exposure to short days is essential for SWC reduction, 24-kD protein accumulation, and freeze-tolerance enhancement. Water deficit induced 24-kD protein accumulation and enhanced freeze-tolerance under long-day conditions. In all instances, freeze-tolerance enhancement and 24-kD protein accumulation was preceded by a reduction of SWC. These results are consistent with the hypothesis that C. sericea responds to decreasing photoperiod, which triggers a reduction in SWC. Reduced SWC in turn may trigger the accumulation of the 24-kD protein and a parallel increase in freeze-tolerance.
先前发现，红枝山茱萸（Cornus sericea L.）茎中一种主要的24-kD脱水素样蛋白会随季节波动。本研究试图确定哪些环境信号触发了24-kD蛋白的积累，并评估其在冬季存活中的潜在作用。对照光周期和田间研究证实，光周期调节茎含水量（SWC）的降低、抗冻性增强以及24-kD蛋白的积累。已知对不同临界光周期有反应的不同气候生态型，表现出SWC降低和24-kD蛋白积累的差异。一项时间进程研究证实，长时间暴露于短日照对于SWC降低、24-kD蛋白积累和抗冻性增强至关重要。水分亏缺在长日照条件下诱导24-kD蛋白积累并增强抗冻性。在所有情况下，抗冻性增强和24-kD蛋白积累之前均有SWC降低。这些结果与以下假设一致：红枝山茱萸对光周期缩短作出反应，这会触发SWC降低。SWC降低反过来可能触发24-kD蛋白的积累以及抗冻性的平行增加。
