Donnelly Alison, Craigon Jim, Black Colin R., Colls Jeremy J., Landon Geoff
School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
Physiol Plant. 2001 Apr;111(4):501-511. doi: 10.1034/j.1399-3054.2001.1110410.x.
This study examined the impact of season-long exposure to elevated carbon dioxide (CO2) and ozone (O3), individually and in combination, on leaf chlorophyll content and gas exchange characteristics in potato (Solanum tuberosum L. cv. Bintje). Plants grown in open-top chambers were exposed to three CO2 (ambient, 550 and 680 µmol mol-1) and two O3 treatments (ambient and elevated; 25 and 65 nmol mol-1, 8 h day-1 means, respectively) between crop emergence and maturity; plants were also grown in unchambered field plots. Non-destructive measurements of chlorophyll content and visible foliar injury were made for all treatments at 2-week intervals between 43 and 95 days after emergence. Gas exchange measurements were made for all except the intermediate 550 µmol mol-1 CO2 treatment. Season-long exposure to elevated O3 under ambient CO2 reduced chlorophyll content and induced extensive visible foliar damage, but had little effect on net assimilation rate or stomatal conductance. Elevated CO2 had no significant effect on chlorophyll content, but greatly reduced the damaging impact of O3 on chlorophyll content and visible foliar damage. Light-saturated assimilation rates for leaves grown under elevated CO2 were consistently lower when measured under either elevated or ambient CO2 than in equivalent leaves grown under ambient CO2. Analysis of CO2 response curves revealed that CO2-saturated assimilation rate, maximum rates of carboxylation and electron transport and respiration decreased with time. CO2-saturated assimilation rate was reduced by elevated O3 during the early stages of the season, while respiration was significantly greater under elevated CO2 as the crop approached maturity. The physiological origins of these responses and their implications for the performance of potato in a changing climate are discussed.
本研究考察了整个生长季单独或联合暴露于高浓度二氧化碳（CO₂）和臭氧（O₃）对马铃薯（Solanum tuberosum L. cv. Bintje）叶片叶绿素含量和气体交换特性的影响。在开放式气室中生长的植株，在作物出苗至成熟期间，接受三种CO₂处理（环境浓度、550和680 µmol mol⁻¹）和两种O₃处理（环境浓度和升高浓度；分别为25和65 nmol mol⁻¹，日均值8小时）；植株也种植在无气室的田间地块。在出苗后43至95天期间，每隔2周对所有处理进行叶绿素含量的无损测量和可见叶损伤观察。除中间浓度550 µmol mol⁻¹的CO₂处理外，对所有处理进行了气体交换测量。在环境CO₂浓度下整个生长季暴露于高浓度O₃会降低叶绿素含量并导致广泛的可见叶损伤，但对净同化率或气孔导度影响较小。高浓度CO₂对叶绿素含量无显著影响，但大大降低了O₃对叶绿素含量和可见叶损伤的破坏作用。在高浓度CO₂下生长的叶片，无论在高浓度还是环境CO₂浓度下测量，其光饱和同化率始终低于在环境CO₂浓度下生长的同等叶片。对CO₂响应曲线的分析表明，CO₂饱和同化率、羧化和电子传递以及呼吸作用的最大速率随时间下降。在生长季早期，高浓度O₃降低了CO₂饱和同化率，而随着作物接近成熟，在高浓度CO₂下呼吸作用显著增强。讨论了这些响应的生理起源及其对马铃薯在气候变化条件下表现的影响。
