Ecophysiology of Plants, Department of Ecology and Ecosystem Management, Technische Universität München, Von-Carlowitz-Platz 2, 85354 Freising, Germany.
Lehrstuhl für Grünlandlehre, Department of Plant Sciences, Technische Universität München, Alte Akademie 12, 85350 Freising, Germany; Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
Environ Pollut. 2015 Jan;196:534-43. doi: 10.1016/j.envpol.2014.08.022. Epub 2014 Oct 12.
Allocation of recent photoassimilates of juvenile beech and spruce in response to twice-ambient ozone (2 × O(3)) and plant competition (i.e. intra vs. inter-specific) was examined in a phytotron study. To this end, we employed continuous (13)CO(2)/(12)CO(2) labeling during late summer and pursued tracer kinetics in CO(2) released from stems. In beech, allocation of recent photoassimilates to stems was significantly lowered under 2 × O(3) and increased in spruce when grown in mixed culture. As total tree biomass was not yet affected by the treatments, C allocation reflected incipient tree responses providing the mechanistic basis for biomass partitioning as observed in longer experiments. Compartmental modeling characterized functional properties of substrate pools supplying respiratory C demand. Respiration of spruce appeared to be exclusively supplied by recent photoassimilates. In beech, older C, putatively located in stem parenchyma cells, was a major source of respiratory substrate, reflecting the fundamental anatomical disparity between angiosperm beech and gymnosperm spruce.
在植物温室内的一项研究中，我们通过在夏末对（13）CO（2）/（12）CO（2）进行连续标记，并追踪从茎中释放的 CO（2）中的示踪剂动力学，来检测幼年山毛榉和云杉对两次环境臭氧（2×O（3））和植物竞争（即种内与种间）的近期光合作用产物的分配。在山毛榉中，在 2×O（3）下，近期光合作用产物向茎的分配明显降低，而在混合培养的云杉中则增加。由于总树木生物量尚未受到处理的影响，C 的分配反映了初期的树木响应，为在更长的实验中观察到的生物量分配提供了机制基础。区室模型表征了供应呼吸 C 需求的基质库的功能特性。云杉的呼吸似乎仅由近期的光合作用产物供应。在山毛榉中，推测位于茎薄壁细胞中的较老的 C 是呼吸基质的主要来源，这反映了被子植物山毛榉和裸子植物云杉之间基本的解剖差异。
