Häikiö Elina, Freiwald Vera, Julkunen-Tiitto Riitta, Beuker Egbert, Holopainen Toini, Oksanen Elina
Department of Environmental Science, University of Kuopio, FI-70211 Kuopio, Finland.
Tree Physiol. 2009 Jan;29(1):53-66. doi: 10.1093/treephys/tpn005. Epub 2008 Dec 3.
The authors analyzed a suite of leaf characteristics that might help to explain the difference between ozone-sensitive and ozone-tolerant hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) clones. An open-field experiment comprising ambient ozone and 1.5x ambient ozone concentration (about 35 ppb) and two soil nitrogen regimes (60 and 140 kg N ha(-1) year(-1)) was conducted over two growing seasons on potted plants of eight hybrid aspen clones. Four of the clones had previously been determined to be ozone sensitive based on impaired growth in response to elevated ozone concentration. Photosynthetic rate, chlorophyll fluorescence, and concentrations of chlorophyll, protein and carbohydrates were analyzed three times during the second growing season, and foliar phenolic concentrations were measured at the end of the second growing season. Nitrogen amendment counteracted the effects of ozone, but had no effect on growth-related ozone sensitivity of the clones. Ozone-sensitive clones had higher photosynthetic capacity and higher concentrations of Rubisco and phenolics than ozone-tolerant clones, but the effects of ozone were similar in the sensitive and tolerant groups. Nitrogen addition had no effect on phenolic concentration, but elevated ozone concentration increased the concentrations of chlorogenic acid and (+)-catechin. This study suggests that condensed tannins and catechin, but not salicylates or flavonol glycosides, play a role in the ozone tolerance of hybrid aspen.
作者分析了一系列叶片特征，这些特征可能有助于解释对臭氧敏感和耐臭氧的杂交白杨（Populus tremula L. x Populus tremuloides Michx.）无性系之间的差异。在两个生长季节中，对八个杂交白杨无性系的盆栽植物进行了一项野外试验，试验包括环境臭氧浓度和1.5倍环境臭氧浓度（约35 ppb）以及两种土壤氮素水平（60和140 kg N ha(-1) 年(-1)）。其中四个无性系先前已根据对升高的臭氧浓度的生长受损情况被确定为对臭氧敏感。在第二个生长季节中三次分析了光合速率、叶绿素荧光以及叶绿素、蛋白质和碳水化合物的浓度，并在第二个生长季节结束时测量了叶片酚类物质的浓度。氮素添加抵消了臭氧的影响，但对无性系与生长相关的臭氧敏感性没有影响。对臭氧敏感的无性系比耐臭氧的无性系具有更高的光合能力以及更高浓度的核酮糖-1,5-二磷酸羧化酶和酚类物质，但臭氧对敏感组和耐受组的影响相似。添加氮素对酚类物质浓度没有影响，但升高的臭氧浓度增加了绿原酸和（+）-儿茶素的浓度。这项研究表明，缩合单宁和儿茶素而非水杨酸盐或黄酮醇糖苷在杂交白杨的耐臭氧性中起作用。
