Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria (EEA) Mendoza, San Martin 3853, Luján de Cuyo (5507), Mendoza, Argentina; and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Rivadavia 1917, ciudad Autónoma de Buenos Aires, C1033AAJ, Argentina.
Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria (EEA) Mendoza, San Martin 3853, Luján de Cuyo (5507), Mendoza, Argentina.
Funct Plant Biol. 2021 Feb;48(3):342-357. doi: 10.1071/FP20212.
Photosynthesis acclimation to high temperature differs among and within species. Grapevine intra-specific variation in photosynthetic acclimation to elevated temperature has been scarcely assessed. Our objectives were to (i) evaluate the mechanisms underlying long-term acclimation of photosynthesis to elevated temperature in grapevine, and (ii) determine whether these responses are similar among two varieties. A warming experiment with well irrigated Grenache and Syrah field-grown plants was performed during two growing seasons comparing plants exposed at ambient temperature (control) with plants in open-top chambers (heating) that increased mean air temperature between 1.5 and 3.6°C. Photosynthetic acclimation was assessed through the response of net assimilation (An), Rubisco carboxylation rate (Vcmax) and electron transport rate (Jmax), at leaf temperatures from 20 to 40°C. Our results evidenced different mechanisms for photosynthetic acclimation to elevated temperature. Compared with control, Grenache heated increased An, maintaining higher Vcmax and Jmax at temperatures above 35°C. By contrast, Syrah heated and control presented similar values of An, Vcmax and Jmax, evidencing an adjustment of photosynthesis without increasing C assimilation. Both varieties increased the optimum temperature for An, but to a lesser extent when growth temperature was higher. Our study provides evidence that grapevine varieties present different acclimation mechanisms to expected warming.
光合作用对高温的适应在不同物种和同一物种内都有所不同。葡萄属植物对高温的光合作用适应的种内变异尚未得到充分评估。我们的目标是：（i）评估葡萄光合作用对高温长期适应的机制，（ii）确定这些响应在两个品种之间是否相似。在两个生长季节中，对充分灌溉的 Grenache 和 Syrah 田间生长的葡萄进行了升温实验，比较了在环境温度下暴露的植物（对照）和在开顶室中暴露的植物（加热），开顶室将空气平均温度提高了 1.5 至 3.6°C。通过在 20 至 40°C 的叶片温度下测定净同化（An）、Rubisco 羧化速率（Vcmax）和电子传递速率（Jmax）来评估光合作用的适应能力。我们的结果表明，葡萄对高温的光合作用适应有不同的机制。与对照相比，加热的 Grenache 增加了 An，在 35°C 以上的温度下保持了更高的 Vcmax 和 Jmax。相比之下，加热的 Syrah 和对照表现出相似的 An、Vcmax 和 Jmax 值，表明光合作用的调节而不增加 C 同化。两个品种都增加了 An 的最佳温度，但在生长温度较高时，增加的幅度较小。我们的研究提供了证据表明，葡萄品种对预期变暖表现出不同的适应机制。
