Department of Biology and The Biotron Experimental Climate Change Research Centre, The University of Western Ontario, London, ON N6A 5B7, Canada.
Physiol Plant. 2012 Feb;144(2):169-88. doi: 10.1111/j.1399-3054.2011.01513.x. Epub 2011 Nov 29.
The contributions of phenotypic plasticity to photosynthetic performance in winter (cv Musketeer, cv Norstar) and spring (cv SR4A, cv Katepwa) rye (Secale cereale) and wheat (Triticum aestivum) cultivars grown at either 20°C [non-acclimated (NA)] or 5°C [cold acclimated (CA)] were assessed. The 22-40% increase in light-saturated rates of CO₂ assimilation in CA vs NA winter cereals were accounted for by phenotypic plasticity as indicated by the dwarf phenotype and increased specific leaf weight. However, phenotypic plasticity could not account for (1) the differential temperature sensitivity of CO₂ assimilation and photosynthetic electron transport, (2) the increased efficiency and light-saturated rates of photosynthetic electron transport or (3) the decreased light sensitivity of excitation pressure and non-photochemical quenching between NA and NA winter cultivars. Cold acclimation decreased photosynthetic performance of spring relative to winter cultivars. However, the differences in photosynthetic performances between CA winter and spring cultivars were dependent upon the basis on which photosynthetic performance was expressed. Overexpression of BNCBF17 in Brassica napus generally decreased the low temperature sensitivity (Q₁₀) of CO₂ assimilation and photosynthetic electron transport even though the latter had not been exposed to low temperature. Photosynthetic performance in wild type compared to the BNCBF17-overexpressing transgenic B. napus indicated that CBFs/DREBs regulate not only freezing tolerance but also govern plant architecture, leaf anatomy and photosynthetic performance. The apparent positive and negative effects of cold acclimation on photosynthetic performance are discussed in terms of the apparent costs and benefits of phenotypic plasticity, winter survival and reproductive fitness.
研究了在 20°C（非驯化（NA））或 5°C（驯化（CA））下生长的冬季（cv Musketeer，cv Norstar）和春季（cv SR4A，cv Katepwa）黑麦（Secale cereale）和小麦（Triticum aestivum）品种的表型可塑性对光合作用性能的贡献。CA 与 NA 冬季谷物中光饱和 CO₂同化率增加 22-40%归因于表型可塑性，表型为矮化和增加的比叶重。然而，表型可塑性无法解释（1）CO₂同化和光合电子传递的温度敏感性差异，（2）光合电子传递效率和光饱和率的增加，或（3）在 NA 和 NA 冬季品种之间激发压力和非光化学猝灭的光敏感性降低。驯化降低了春季与冬季品种的光合作用性能。然而，CA 冬季和春季品种之间的光合作用性能差异取决于表达光合作用性能的基础。在 Brassica napus 中过表达 BNCBF17 通常会降低 CO₂同化和光合电子传递的低温敏感性（Q₁₀），尽管后者没有暴露于低温下。与过表达 BNCBF17 的转基因 Brassica napus 相比，野生型的光合作用性能表明 CBFs/DREBs 不仅调节抗冻性，还调节植物结构、叶片解剖结构和光合作用性能。从表型可塑性、冬季生存和生殖适应性的明显成本和收益的角度讨论了驯化对光合作用性能的明显积极和消极影响。
