Ozone Impacts on Competition between Tomato and Yellow Nutsedge: Above‐ and Below‐Ground Effects

Abstract

Tomato (Lycopersicon esculentum L.) production in the San Joa- Reinert and Henderson, 1980), and in California (Brewer quin Valley (SJV) of California is challenged by air pollution and weeds. Differential ozone (O 3 ) tolerance of tomato cultivars and weed species Temple et al., 1985). Yield losses of 31% were may alter crop-weed competition. A study was conducted in open top

Flixweed Is More Competitive than Winter Wheat under Ozone Pollution: Evidences from Membrane Lipid Peroxidation, Antioxidant Enzymes and Biomass

“…In the present study, chlorophyll contents of both winter wheat and flixweed significantly declined under the conditions of both elevated [O 3 ] and high [O 3 ] (Figure 1). It is the typical symbol of O 3 impacts on leaf pigmentation in plants as documented by previous investigations [16], [33]. However, the reduction in flixweed was less than wheat under the same treatment, suggesting flixweed was more tolerant to O 3 than wheat.…”

“…Alterations of the competitive balance expressed by total biomass and grain yield were similar to Li et al (1999) [22], who argued that higher antioxidant capacity and strong survivability to O 3 were the main causes of stress adaption and species competition superiority. In many weedy species, short life cycles, as well as prolific production and dispersal, will accelerate adaptation to higher ambient O 3 concentration [33]. From the above mentioned findings, we believe that the higher negative response of wheat is due to the competition co-existed between wheat and flixweed, and to higher susceptibility of wheat to O 3 stress during the seed filling stage [47].…”

Ozone Sensitivity Differences in Five Tomato Cultivars: Visible Injury and Effects on Biomass and Fruits

“…Finally, our results show a higher growth rate in the ozone chambers (P<0.001 time×treatment) but also a more rapid crop senescence. This can be regarded as a mechanism to compensate the loss of photosynthetically active biomass when the oldest leaves are completely dry, as has been reported for the tomato (Shrestha and Grantz 2005). At the end of crop the least sensitive cultivar (Piedmont) showed some recovery in root and aboveground biomass, because it is the only cultivar that shows a significant increase in the total number of leaves in the NF+ treatment and no significant differences in the dry leaves percentage between treatments.…”

“…In addition to crop yield studies, tomato responses to ozone have been observed in biomass, growth (Olszyk and Wise 1997), increasing of defense mechanisms (Langebartels et al 2002), parameters of chlorophyll fluorescence Barreno 2000, 2001), several biochemical and molecular responses (Nakajima et al 2001;Cosima et al 2003;Pirker et al 2003) and also in the photosynthetic parameters (Hassan et al 1999;Moeder et al 2002;Guidi et al 2004). Finally, there have also been studies on the interactions between ozone and diseases, as in the case of nematodes (Khan and Khan 1997) and viruses (Jimenez et al 2001), as well as other interactions such as ozone and uv radiation (Hao et al 2000) or competition with other plants (Shrestha and Grantz 2005). In spite of the evidence of ozone sensitivity in the tomato, there are few studies on the chronic effects of ozone on tomato cultivars, and few observations of the effect of ozone on tomato fruit quality.…”

Plant-Mediated Ecosystem Effects of Tropospheric Ozone

“…Unfortunately, overall knowledge about this issue is rather scarce. Ozone impacts on competition between crops and the C-4 weed Cyperus esculentus have been investigated by Shrestha (2005, 2006) and Shrestha and Grantz (2005). Fruit productivity of Lycopersicon esculentum in competition with this weed was reduced under low and moderate O 3 levels, whereas the crop responded only to high O 3 levels in the absence of the weed .…”