Gardner Simon D L, Taylor Gail, Bosac Creana
School of Biological Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9QG, UK.
New Phytol. 1995 Sep;131(1):81-90. doi: 10.1111/j.1469-8137.1995.tb03057.x.
Leaf extension was stimulated following exposure of three interamerican hybrid poplar clones (Populus trichocarpa P. deltoides); 'Unal', 'Boelare', and 'Beaupre' and a euramerican clone 'Primo' (Populus nigra×P. deltoides) to elevated CO , in controlled environment chambers. For all three interamerican clones the evidence suggests that this was the result of increased leaf cell expansion associated with enhanced cell wall extensibility (WEx), measured as tensiomerric increases in cell wall plasticity. For the interameriean clone 'Boelare', there was also a significant increase in cell wall elasticity following exposure to elevated CO (P⩽ 0.001). The effect of elevated CO in stimulating cell wall extensibility was confirmed in a detailed spatial analysis of extensibility made across the lamina of expanding leaves of the clone 'Boelare'. For two of the interamerican hybrids, 'Unal' and 'Beaupre', both leaf cell water potential Ψ and turgor pressure (P) were lower in elevated than in ambient CO . By contrast, no significant effects on the cell wall properties or leaf water relations for the euramerican hybrid 'Primo' were observed following exposure to elevated CO . suggesting that the mechanism for increased leaf extension in elevated CO , differed, depending on clone. The cumulative total length of leaves of 'Boelare' grown in elevated CO , was significantly increased (P≤ 0.05) and since leaf number was not significantly increased in any inter-american clone it is hypothesized that final leaf size was stimulated in elevated CO for these clones. By contrast, there was no significant effect of CO on cumulative total leaf length for the euramerican clone 'Primo', but leaf number was significantly increased by elevated CO . The measurements suggest that total tree leaf area was stimulated for a range of poplar hybrids exposed to elevated CO . Given the short rotation of a coppiced crop, it is likely that increased leaf areas will result in enhanced stemwood production when hybrid poplars are grown in the CO, concentrations predicted for the next century.
在可控环境舱中，将三个美洲杂种杨树无性系（毛果杨×美洲黑杨）“Unal”“Boelare”和“Beaupre”以及一个欧美杂种无性系“Primo”（黑杨×美洲黑杨）暴露于高浓度二氧化碳环境下后，叶片伸展受到刺激。对于所有三个美洲杂种无性系而言，有证据表明这是叶片细胞扩张增加的结果，这种增加与细胞壁伸展性（WEx）增强相关，细胞壁伸展性通过细胞壁可塑性的张力测定增加来衡量。对于美洲杂种无性系“Boelare”，暴露于高浓度二氧化碳后，细胞壁弹性也显著增加（P≤0.001）。通过对“Boelare”无性系正在伸展叶片的叶片进行详细的伸展性空间分析，证实了高浓度二氧化碳对刺激细胞壁伸展性的作用。对于两个美洲杂种“Unal”和“Beaupre”，高浓度二氧化碳环境下叶片细胞水势Ψ和膨压（P）均低于环境二氧化碳环境下。相比之下，欧美杂种“Primo”暴露于高浓度二氧化碳后，未观察到对细胞壁特性或叶片水分关系有显著影响，这表明高浓度二氧化碳环境下叶片伸展增加的机制因无性系而异。在高浓度二氧化碳环境下生长的“Boelare”叶片的累计总长度显著增加（P≤0.05），并且由于任何美洲杂种无性系的叶片数量均未显著增加，因此推测这些无性系在高浓度二氧化碳环境下最终叶片大小受到刺激。相比之下，高浓度二氧化碳对欧美杂种无性系“Primo”的累计总叶长没有显著影响，但高浓度二氧化碳显著增加了叶片数量。这些测量结果表明，一系列杨树杂种暴露于高浓度二氧化碳后，总树叶面积受到刺激。鉴于矮林作物的轮伐期较短，当杂种杨树在下个世纪预计的二氧化碳浓度下生长时，叶面积增加可能会导致茎材产量提高。
