INSTYTUT DENDROLOGII

POLSKIEJ AKADEMII NAUK

47:09-19

Ludwig De Temmerman, Karine Vandermeiren, David D'Haese, Katrien Bortier, Han Asard, Reinhart Ceulemans

Ozone effects on trees, where uptake and detoxification meet

Dendrobiology 2002, vol. 47: 09-19 Full text (pdf)

Abstract: Ozone is the most important air pollutant and its concentration in ambient air is still rising. Ozone concentrations measured at reference height (50 m is EMEP ozone modelling height), do not reflect the real concentration at the top of the vegetative canopy and do not provide sufficient information about the ozone fluxentering the leaves. Modelling stomatal conductance is leading to estimations of cumulative ozone uptake and enables much better to evaluate the impact of ozone on trees. The negative impact of ozone exposure has a measurable effect on physiological processes such as stomatal conductance, photosynthesis and respiration. Disturbance of the basic physiological processes is leading to growth and wood production losses. There have been several attempts to establish critical levels (CL) for ozone effects on forest trees. Average concentrations and cumulative exposure indices are satisfactory to some extent, but do not fully describe the potential impact of ozone exposure. Much more promising is an evaluation based on the effective ozone flux, which is a function of the absorbed ozone flux and the defensive response. Ozone uptake takes place primarily through the stomata and reactions of ozone with hydrocarbons released by the plant cells and transformations of dissolved ozone in the apoplastic fluid create many reactive oxygen species of which free radicals are able to initiate membrane lipid peroxidation and destruction of cell membranes. The defence of a plant against absorbed ozone starts in the apoplastic fluid. Ascorbate is believed to be a very important radical scavenger avoiding detrimental effects of reactive oxygen species to the membranes. Other important antioxidants are phenolics. The defensive response can be linked to the abundance of ascorbate or the ability of the plants to regenerate (reduce) ascorbate from monodehydroascorbate and dehydroascorbate. The reduction of dehydroascorbate takes place in the symplast where ascorbate can be transported back through the plasma membrane into the apoplast. Ozone exposure also causes oxidative stress of the plant cell interior by the formation of reactive oxygen species. Plants can cope with those toxic substances in the symplast by using antioxidants such as ascorbate, -tocopherol, glutathione and carotenoids and enzymes such as superoxide dismutases, catalases and several peroxidases. The complexity of the apoplastic and symplastic antioxidative capacity with different turnover rates and transport of antioxidants makes it difficult to determine the total antioxidative power.

Additional key words:Trees, effective ozone flux, oxidative defence, critical levels for ozone

 

     

Zmień kontrast

Dostosuj czcionkę

eu logo

HR 01

W ramach dotacji Powiatu Poznańskiego na prace konserwatorskie, restauratorskie lub roboty budowlane przy zabytku, nasze Arboretum otrzymało środki na realizację projektu pt. Wyeksponowanie oryginalnych elementów zabytkowego ogrodu poprzez przebudowę odcinka alejek parkowych w Arboretum w Kórniku.

powiatpozn

Przedsięwzięcie pn.: "Doposażenie sal edukacyjnych Instytutu Dendrologii Polskiej Akademii Nauk w Kórniku w sprzęt i pomoce naukowe potrzebne do prowadzenia edukacji przyrodniczej i ekologicznej" dofinansowano ze środków Wojewódzkiego Funduszu Ochrony Środowiska i Gospodarki Wodnej w Poznaniu. 

 

Zakup sprzętu i oprogramowania, materiałów i pomocy dydaktycznych wykorzystywanych w działalności edukacyjnej Instytutu Dendrologii PAN oraz opracowanie i wydruk przewodników przyrodniczych dla dzieci.

WFOSüGW Nowe logo peéna nazwa KOLOR

OZwRCIN extended colour RGB

Repozytorium Cyfrowe ID PAN

facebook idpan button

OZwRCIN logo