Foliar responses to ozone of Fagus sylvatica L. seedlings grown in shaded and in full sunlight conditions
Foliar responses to ozone of Fagus sylvatica L. seedlings grown in shaded and in full sunlight conditions
复制标题
DOI：
10.1016/j.envexpbot.2009.10.003
复制
发表时间：
2010-04-01
影响因子：
5.7
通讯作者：
Strasser, Reto J.
中科院分区：
文献类型：
--
作者：
Cascio, Chiara;Schaub, Marcus;Strasser, Reto J.
众所周知，臭氧 (O-3) 在实验条件下会影响树苗的光合作用。在自然条件下，幼树在竞争性环境下生长，这可能会改变光的可用性。在瑞士南部（Lattecaldo）进行的开顶室（OTC）实验中模拟了此类条件。实验设置包括水青冈（山毛榉）幼苗地块（种植在同一室内），或者是单一种群（单种，在全日照条件下生长的叶子-FL），或者是与较高的马缨丹植物（混合、遮荫叶子-SH）竞争。这些培养物用环境空气（NF，未过滤，环境空气中臭氧含量为 92%）和木炭过滤空气（CF，环境空气中臭氧含量为 50%）处理。净光合作用 (P-N) 和叶绿素 a 荧光（通过 OKJIP 瞬态分析）的测量是在 6 月至 9 月的生长季节进行的。单光条件下（全光叶），净光合作用 (P-N) 和到达受体侧的电子最大量子产率 (phi(Ro) = RE0/ABS) 较高。反之亦然，初级光化学的量子产率 (phi(Po) = TR0/ABS = F-V/F-M) 和吸收基础性能指数 (PIABS) 在混合图（阴影叶子）中较高。臭氧引起的变化仅发生在生长季节末（九月）。臭氧主要影响 PN，与 CF 相比，PN 的影响较低，无论是单一（-19%）还是混合（-28%）地块。与臭氧暴露相比，荧光参数受光照条件（全光与阴影叶子）的影响更大，但臭氧通过降低 TR0/ABS 和 PIABS 的值来增强高光的作用。臭氧最具体的影响涉及 RE0/ABS 的减少，这表明电子末端受体失活，从而产生过量的氧化压力。讨论了臭氧对森林再生过程的影响的结果。 (C) 2009 Elsevier B.V. 保留所有权利。
Ozone (O-3) is well known to affect photosynthesis on tree seedlings under experimental conditions. In natural conditions, young trees grow under a competitive environment that may alter light availability. Such conditions were simulated in an open-top chamber (OTC) experiment carried out in Southern Switzerland (Lattecaldo). The experimental set-up consisted of Fagus sylvatica (beech) seedling plots (planted within the same chamber) either in a monospecific population (Mono, leaves grown in full sunlight conditions-FL) or under competition with taller plants of Viburnum lantana (Mixed, shaded leaves-SH). These Cultures were treated with ambient air (NF, not filtered, 92% of ozone in ambient air) and with charcoal filtered air (CF, 50% of ozone in ambient air). Measures of net photosynthesis (P-N) and chlorophyll a fluorescence (with the analysis of the OKJIP transient) were performed over a growing season, from June to September. Net photosynthesis (P-N) and the maximum quantum yield of electrons reaching the acceptor side (phi(Ro) = RE0/ABS) were higher in Mono conditions (full light leaves). Vice versa, quantum yield of primary photochemistry (phi(Po) = TR0/ABS = F-V/F-M) and Performance Index on absorption basis (PIABS) were higher in Mixed plots (shaded leaves). Changes due to ozone occurred only at the end of the growing season (September). Ozone affected mainly PN, that was lower in the NF-OTCs, both Mono (-19%) and Mixed (-28%) plots, compared to the CF ones. Fluorescence parameters were affected much more by light conditions (full light vs. shaded leaves) than ozone exposure, but ozone enhanced the action of high light by lowering the values of TR0/ABS and PIABS. The most specific effect of ozone concerned the decrease in RE0/ABS, that indicates the inactivation of the end acceptors of electrons, so producing an excess of oxidative pressure. Results are discussed in relation to the impact of ozone on the processes of the regeneration of forests. (C) 2009 Elsevier B.V. All rights reserved.