The effects of enhanced ozone and enhanced carbon dioxide concentrations on biomass, pigments and antioxidative enzymes in spruce needles (Picea abies L.)

Abstract

During one growing period, 5‐year‐old spruce trees (Picea abies L., Karst.) were exposed in environmental chambers to elevated concentrations of carbon dioxide (750 cm3 m−3) and ozone (008 cm3 m−3) as single variables or in combination. Control concentrations of the gases were 350cm3 m−3CO2 and 0.02 cm3 m −3 ozone. To investigate whether an elevated CO2 concentration can prevent adverse ozone effects by reducing oxidative stress, the activities of the protective enzymes superoxide dismutase, catalase and peroxidase were determined. Furthermore, shoot biomass, pigment and protein contents of two needle age classes were investigated. Ozone caused pigment reduction and visible injury in the previous year's needles and growth reduction in the current year's shoots. In the presence of elevated concentrations of ozone and CO2, growth reduction in the current year's shoots was prevented, but emergence of visible damage in the previous year's needles was only delayed and pigment reduction was still found. Elevated concentrations of ozone or CO2 as single variables caused a significant reduction in the activities of superoxide dismutase and catalase in the current year's needles. Minimum activities of superoxide dismutase and catalase and decreased peroxidase activities were found in both needle age classes from spruce trees grown at enhanced concentrations of both CO2 and ozone. These results suggest a reduced tolerance to oxidative stress in spruce trees under conditions of elevated concentrations of both CO2 and ozone.

Effects of elevated CO2, O3 and K deficiency on Norway spruce (Picea abies): nutrient supply, content and leaching

“…This implies that uptake and transfer of these nutrients into the current-year needles did not satisfy the demand generated by enhanced growth at elevated CO, (see Norby, O'Neill & Luxmore, 1986;Polle et al, 1993). However, care needs to be taken in the interpretation of these data because starch accumulated in the needles of CO2-enriched trees over the course of the season (Barnes et al, 1995a).…”

Tree and forest functioning in an enriched CO2 atmosphere

“…The negative impact of O $ on  was related to increased leaf dark respiration, decreased photosynthesis and\or decreased . Kull et al (1996) Polle et al (1993) did not find that CO # enrichment protected against O $ stress by increasing protective enzymes. Ozone reduced growth in current-year shoots, whereas CO # prevented this.…”

Elevated concentrations of atmospheric CO2 protect against and compensate for O3 damage to photosynthetic tissues of field‐grown wheat

“…In combination, ozone damage to photosynthetic tissues is ameliorated by elevated [CO # ], and recent studies have examined the mechanisms behind this interaction (Kramer et al, 1991 ;Polle et al, 1993 ;McKee et al, 1995McKee et al, , 1997bRao et al, 1995 ;Booker et al, 1997 ;Volin et al, 1998 ;Wieser et al, 1998). In controlled-environment studies, in which spring wheat was exposed to chronically elevated concentrations of CO # and\or O $ , the effect of elevated [O $ ] on photosynthesis resulted mainly from a loss of Rubisco activity (McKee et al, 1995(McKee et al, , 1997b.…”

“…7) , 1997bFiscus et al, 1997) ; this protective effect, as shown in this study, might be less consistent under variable field conditions. Second, greater availability of photosynthate under elevated [CO # ] might enhance detoxification capacity (Rao et al, 1995), although some studies suggest that this may be of minor importance (Polle et al, 1993 ;McKee et al, 1997b $ -sensitive Rubisco limitation to the relatively insensitive RuBP-regeneration limitation. In this experiment, a compensatory shift in photosynthetic control was also observed in the flag leaf at noon on Day III (Fig.…”