Frey Beat, Scheidegger Christoph, Günthardt-Goerg Madeleine S, Matyssek Rainer
Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse III, CH-8903 Birmensdorf, Switzerland.
New Phytol. 1996 Jan;132(1):135-143. doi: 10.1111/j.1469-8137.1996.tb04519.x.
Cuttings of Betula pendula Roth were grown in field fumigation chambers throughout one growing season in filtered air with < 3 nl l O (control; C) or day/night = 90/40 nl 1 O (ozone fumigation: O ). Plants were watered with either low (0·005 %: LF) or high-concentrated (0·05%: HF) fertilizer solution. Discs between second-order veins in the central portion of the leaves were excised and immediately cryofixed in liquid nitrogen for low-temperature scanning electron-microscopy (LTSEM) at 1000 hours and 1400 hours. Stomatal width, area and density were measured by digital image-analysis. X-ray counts of potassium (K) and calcium (Ca) ions were determined by means of energy-dispersive X-ray microanalysis in guard and subsidiary cells. Accurate and fast measurements of stomatal apertures by image analysis were possible in birch leaves, because the darkness of the stomatal pore contrasts with the brightness of the guard cells and the cuticular ledges. Regression analysis showed a close relationship between the stomatal width and the pore area (r= 0·938, P < 0·01). At all harvest times, the stomatal pores were significantly narrowed in the high fertilization control treatment (O /HF vs. O /LF), and in the ozone treatment at 1400 hours (O /HF vs. C/LF). In addition to this fertilization effect, ozone had also narrowed the stomatal pores (O /HF vs. C/HF at 1400 hours, O /LF vs. C/LF at all harvest times). In addition to these functional effects, morphological effects (individual leaf area, stomatal density) were determined. Single-leaf area was increased by high fertilization, with a tendency to decrease with O fumigation. The stomatal density in intercostal fields was increased by O but decreased by high fertilisation. Stomatal widening was accompanied by increased K count rates in the guard cells, in contrast to constant K values in the subsidiary cells, irrespective of the fumigation or fertilization regimes. Calcium counts in the guard cells were similar to those in the subsidiary cells, and were independent of the aperture width. In samples with established ozone injury, the K/Ca ratio in collapsed guard cells increased compared with turgid guard cells irrespective of the pore aperture. Collapsed subsidiary cells only differed from turgid subsidiary cells when the guard cells had also collapsed and thus closed the pore.
在一个生长季节里，将欧洲白桦（Betula pendula Roth）的插条种植在田间熏蒸室中，使其处于过滤空气中，其中一种处理的氧气含量<3 nl l（对照；C），另一种处理的日/夜氧气含量=90/40 nl 1（臭氧熏蒸：O）。用低浓度（0.005%：LF）或高浓度（0.05%：HF）的肥料溶液浇灌植株。在1000小时和1400小时，切除叶片中部二级叶脉之间的叶盘，并立即在液氮中进行冷冻固定，以便进行低温扫描电子显微镜（LTSEM）观察。通过数字图像分析测量气孔宽度、面积和密度。利用能量色散X射线微分析测定保卫细胞和副卫细胞中钾（K）和钙（Ca）离子的X射线计数。通过图像分析可以准确快速地测量白桦叶片的气孔孔径，因为气孔孔的暗度与保卫细胞和角质层壁架的亮度形成对比。回归分析表明气孔宽度与孔面积之间存在密切关系（r = 0.938，P < 0.01）。在所有收获时间，高施肥对照处理（O/HF与O/LF）以及1400小时的臭氧处理（O/HF与C/LF）中，气孔孔明显变窄。除了这种施肥效应外，臭氧也使气孔孔变窄（1400小时时O/HF与C/HF，所有收获时间O/LF与C/LF）。除了这些功能效应外，还测定了形态学效应（单叶面积、气孔密度）。高施肥增加了单叶面积，臭氧熏蒸有使其减小的趋势。肋间区域的气孔密度因臭氧熏蒸而增加，但因高施肥而降低。气孔变宽伴随着保卫细胞中钾计数率的增加，与之形成对比的是，无论熏蒸或施肥处理如何，副卫细胞中的钾值保持不变。保卫细胞中的钙计数与副卫细胞中的相似，且与孔径宽度无关。在已出现臭氧损伤的样本中，无论孔径大小，塌陷保卫细胞中的钾/钙比值均高于膨胀保卫细胞。只有当保卫细胞也塌陷并因此关闭气孔时，塌陷的副卫细胞才与膨胀的副卫细胞有所不同。
