Madsen Tom Vindbæk, Brix Hans
Department of Plant Ecology, University of Aarhus, Nordlandsvej 68, DK-8240 Risskov, Denmark fax: +45 89 42 47 47; e-mail:
Oecologia. 1997 Apr;110(3):320-327. doi: 10.1007/s004420050165.
In this study we examine the influence of temperature on growth, photosynthetic performance and acclimation of two submerged macrophyte species, Elodea canadensis L.C. Rich and Ranunculus aquatilis (L.) Wimmer. The plants were grown at 5, 10 and 15°C and a photon flux density of 300 μmol m s (PAR) in a medium with an alkalinity of 0.85 meq l bubbled with atmospheric air containing 400 ppm CO. In general, growth rates of both species increased with temperature with a Q varying from 2.3 to 3.5. An exception was Elodea at 5°C, where growth was nearly arrested. Temperature effects on ambient rates of net photosynthesis and photosynthetic capacity followed the pattern observed for growth. Dark respiration was not suppressed for Elodea at 5°C and both species had a Q of 2.3. The light-use efficiency (α) for photosynthesis declined with increasing growth temperature for Ranunculus. For Elodea no difference in α was observed between 10 and 15°C; at 5°C, however, α was reduced by about 30%. Both species acclimated to temperature as shown in a series of experiments in which the plants were exposed to a change in temperature. Acclimation was faster for shoots transferred from low to high temperature, where growth rates stabilised after a few days; for shoots transferred to low temperature growth rates still changed after 22 days. Although acclimation was evident, the changes in the metabolic apparatus were insufficient to balance effects of temperature. It is suggested that temperature may affect local distribution of the two species and their ability to grow in turbid or deep water.
在本研究中，我们考察了温度对两种沉水植物加拿大伊乐藻（Elodea canadensis L.C. Rich）和水毛茛（Ranunculus aquatilis (L.) Wimmer）生长、光合性能及适应性的影响。这些植物在5℃、10℃和15℃的温度以及300 μmol m⁻² s⁻¹的光合有效辐射（PAR）下培养，培养介质的碱度为0.85 meq l⁻¹，并用含有400 ppm CO₂的大气空气进行曝气。总体而言，两种植物的生长速率均随温度升高而增加，Q₁₀值在2.3至3.5之间变化。例外的是5℃下的加拿大伊乐藻，其生长几乎停滞。温度对净光合速率和光合能力的影响遵循与生长相同的模式。5℃下的加拿大伊乐藻暗呼吸未受抑制，两种植物的Q₁₀值均为2.3。水毛茛的光合作用光利用效率（α）随生长温度升高而下降。对于加拿大伊乐藻，10℃和15℃之间未观察到α的差异；然而，在5℃时，α降低了约30%。在一系列实验中，将植物暴露于温度变化下，结果表明两种植物都能适应温度。从低温转移到高温的茎适应速度更快，几天后生长速率就稳定下来；转移到低温的茎在22天后生长速率仍有变化。尽管适应现象明显，但代谢机制的变化不足以平衡温度的影响。研究表明，温度可能会影响这两种植物的局部分布及其在浑浊或深水环境中的生长能力。
