Ozone threshold doses and exposure–response relationships for the development of ozone injury symptoms in wild plant species

Abstract

The relative ozone sensitivities of 25 German native herbaceous plant species, representative of arable field margins or disturbed habitats, were examined over three consecutive growing seasons. Plants were grown from seed, potted into natural soils and exposed in open-top chambers for the entire season to different ozone-exposure regimes covering a range of concentrations from 5 to 48 ppb (seasonal 8 h daily mean). The assessment of ozone effects was carried out by recording the first day of visible symptom appearance and the percentage of injured leaves at the end of vegetative growth. Species exhibited contrasting patterns of symptom expression under ozone stress, with either ozone-specific symptoms or ozone-enhanced foliar pigmentation and senescence. Classifications of species according to their ozone susceptibility varied depending on whether measurement was of the total extent of visible injury, ozone threshold doses for the incidence of symptoms, or modelled exposure-response relationships. The most sensitive species exhibiting ozone-specific symptoms were Cirsium arvense and Sonchus asper, which responded to accumulated ozone exposures 1500 ppb.h (AOT40). For these and three other species, an AOT40 peak of a single day was found to be responsible for the incidence of ozonespecific symptoms, i.e. injury occurred rapidly within a few days of the day with the highest AOT40, while other species responded only to longer-term ozone exposures. The relative ozone sensitivity of the species was calculated by combining the different sensitivity criteria, and possible systematic trends (taxonomic or evolutionary features) are pointed out. The results suggest it may be possible to use a particular group of native herbaceous plant species with contrasting patterns of ozone sensitivity as a biomonitoring system in the field. This allows plant responses to be related either to peak values or to prolonged ozone exposure, making it possible to distinguish between shortand long-term effects of ozone.

Growth response to ozone of annual species from Mediterranean pastures

“…These types of disagreements in the sensitivity classifications when visible injury or growth-related parameters have been reported by many authors in the literature (see review by Davison and Barnes, 1998). It is worth noting the high sensitivity of the Trifolium species involved in the study, in agreement with Nebel and Fuhrer (1994), Nussbaum et al (1995), Karlsson et al (1995), Balls et al (1996), Ashmore et al (1996), Bergmann et al (1999) and Gimeno et al (2004). Since the ecology of these Trifolium species is quite different, Bergmann et al (1999) suggested that their great sensitivity could be related to evolutionary and genetic features.…”

Trends in ozone levels and identification of visible injuries on agricultural crops in areas in the Metropolitan Zone of Mexico Valley

“…For this reason, ozone concentrations reached maximum values exceeding 110 ppb during for hours (Figure 7). researchers for crops with wide leaves when these are exposed to high ozone levels [2,3,6,7] . The typical damage is irregular, bifacial, marginal and intervein, with necrotic areas, whitish dots, and chlorotic in aged leaves.…”

“…Some research works about exposure of plants from different communities at realistic levels of ozone have been reported, to assess the sensitivity of specific species to this pollutant to determine threshold values of damage and to propose secondary standards for protection to the vegetation [1,6,7,10,17].…”

Foliar injury, growth, and SOD activity of Pinus densiflora exposed to ozone

“…We can therefore compare ozone sensitivity between species using visible injury, growth change induced by ozone, and antioxidant activity (Heath [9], Sheng et al [18], Bergmann et al [3], Bungener et al [5]). Recently there have been many studies conducted to determine plant response to ozone, but the physio-biochemical response to ozone may be expressed in complicated ways, and thus it may difficult to determine the exact relationship between ozone and plant growth.…”