Ozone uptake in the sun and shade crown of spruce: quantifying the physiological effects of ozone exposure

✍ Scribed by Gerhad Wieser; Wilhelm M. Havranek

• Book ID: 104661468
• Publisher: Springer-Verlag
• Year: 1993
• Tongue: English
• Weight: 608 KB
• Volume: 7
• Category: Article
• ISSN: 0931-1890
• DOI: 10.1007/bf00202078

✦ Synopsis

The uptake of air pollutants depends both on pollutant concentration and on stomatal conductance. This paper deals with the uptake of ozone (03) from the air into the needles of Norway spruce [Picea abies (L.) Karst.] under ambient climatic conditions. Regulation of 03 uptake by the stomata is shown and also the difference b~tween the "physiologically active 03 concentration" and the 03 concentration of the ambient air. Data from the sun and shade crown of spruce trees at 1000 m a. s. 1. are presented. Analysis of data from three vegetation periods has shown that at low ambient 03 concentrations the 03 uptake is largely regulated by stomatal conductance. Water vapour pressure deficit (VPD) of the atmosphere is the climatic factor which showed the highest positive correlation with 03 concentration. However, a high leaf-air VDP led to stomatal closure, thus reducing the 03 uptake in the needles despite high 03 concentrations in the ambient air. The potential 03 stress caused by high 03 concentrations can be strongly mitigated by this natural closing of the stomata and the simultaneous occurrence of moderate drought stress.