Growth and Yield Responses of Snap Bean to Mixtures of Carbon Dioxide and Ozone

Abstract

Elevated CO 2 concentrations expected in the 21st century can stimulate plant growth and yield, whereas tropospheric 03 suppresses plant growth and yield in many areas of the world. Recent experiments showed that elevated CO 2 often protects plants from 03 stress, but this has not been tested for many important crop species including snap bean (Phaseolus vulgaris L.). The objective of this study was to determine if elevated CO 2 protects snap bean from 03 stress. An O 3 -tolerant cultivar (Tendereffe) and an 0 3 -sensitive selection (S156) were exposed from shortly after emergence to maturity to mixtures of CO 2 and 03 in open-top field chambers. The two CO 2 treatments were ambient and ambient with CO 2 added for 24 h d-l resulting in seasonal 12 h d-l (0800-2000 h EST) mean concentrations of 366 and 697 FL L-l, respectively. The twvo 03 treatments were charcoal-filtered air and nonfiltered air with 03 added for 12 h d-I to achieve seasonal 12 h d-I (0800-2000 h EST) mean concentrations of 23 and 72 nL L', respectively. Elevated CO 2 significantly stimulated growth and pod weight of Tenderette and S156, whereas elevated 03 significantly suppressed growth and pod weight of S156 but not of Tenderette. The suppressive effect of elevated 03 on pod dry weight of S156 was approximately 75% at ambient CO 2 and approximately 60% at elevated CO 2 (harvests combined). This amount of protection from 03 stress afforded by elevated CO 2 was much less than reported for other crop species. Extreme sensitivity to 03 may be the reason elevated CO 2 failed to significantly protect S156 from 03 stress.

Growth and Yield Responses of Potato to Mixtures of Carbon Dioxide and Ozone

“…For example, at ambient CO 2 , total tuber yield at 80 nL L −1 was 88% less than at 15 nL L −1 , whereas at double ambient CO 2 , O 3 did not affect yield. However, at the final harvest of the present study and for a previous study with bean (Heagle et al, 2002), elevated CO 2 did not provide significant protection. Too much O 3 stress may have offset possible protection of bean by elevated CO 2 (Heagle et al, 2002).…”

“…However, at the final harvest of the present study and for a previous study with bean (Heagle et al, 2002), elevated CO 2 did not provide significant protection. Too much O 3 stress may have offset possible protection of bean by elevated CO 2 (Heagle et al, 2002). One reason for protection of Dark Red Norland early in the season but not later may be related to different degrees of O 3 stress.…”

“…An exception occurred for an O 3 –sensitive selection (S156) of bean ( Phaseolus vulgaris L.), however. Ozone injured S156 as much at elevated as at ambient CO 2 , and the response to CO 2 enrichment was similar at all O 3 levels (Heagle et al, 2002).…”

Effects of ozone on growth, net photosynthesis and yield of two African varieties of Vigna unguiculata

“…Huang et al (2004) reported a 60% yield reduction in soybean plants exposed to 100 ppb O 3 . Heagle et al (2002) found that a sensitive snap bean genotype (S156) had a 90.1% reduction in final pod weight under elevated O 3 concentrations (72 nmol mol À1 ). They also reported a 15.4% reduction in final pod weight for an O 3 -tolerant snap bean cultivar (Tenderette) at the same O 3 concentrations.…”

Cultivar-Specific Response of Soybean (Glycine max L.) to Ambient and Elevated Concentrations of Ozone Under Open Top Chambers

“…Gelang et al (2000) observed that accelerated senescence of flag leaves shortened the grain-filling duration and thereby reduced grain yield under elevated O 3 . Another possible reason for O 3 -induced yield loss could be due to toxic effects of O 3 on pollen tube growth and fertilization in wheat (Black et al 2000;Mckee et al 1997;Mulholland et al 1998) or high sensitivity of certain snap bean and potato cultivars to O 3 (Heagle et al 2003;Heagle et al 2002). Wang et al (2007) compared EDU-treated with untreated wheat plants and concluded that local ambient levels of O 3 with an annual mean concentrations of 74 ppb mainly affected wheat but not rice.…”