Catechin, proanthocyanidin and lignin contents of loblolly pine (Pinus taeda) needles after chronic exposure to ozone

Abstract

SUMMARYConcentrations of soluble and bound phenolic cotnpounds were measured in needles of 3-yr-old loblolly pme {Pinus taeda L.) trees exposed from May to November 1993 to a range of ozone (O3) concentrations in open-top fidd chambers. The treatments were charcoal-filtered air (CF). non-filtered air (NF), and NF air with O, added at 1-5 times (NF 1-5) and 2-0 times (NF 2-0) the ambient O, concentration for 12 h daily. Average daily (0800-2000 hours) O3 concentrations in the CF.NF, NF ISandNF 2 0 treatments were r. 29, 47, 76 and 98 nl 1"', respectively, for the 140 d treatment period. At tbe end of the treatment period, total phenolic and proanthoc\anidin concentrations in the previous year's needles were 25-29'\, higher in the NF 2'0 treatment compared v\ ith the lower O., treatments. Catechin concentration increased in the previous year's needles by as mucb as 81 ''" between the NF 2-0 treatment and tbe lower O^ treatments. Catechin is an effective antioxidant, and elevated levels migbt confer some protection against O^ injury. No significant differences in total phenolics and proanthocyanidins in the previous year's needles were detected among the remaining O^ treatments, or among any C>. , treatment for tbe current year's needles. Lignin content in needles of botb years was not significantly affected by O,j exposure. Changes in the phenolic content of older needles in response to elevated O^ could alter plant-patbogen interactions and slow down microbial decomposition, which could contribute to a decline in site soil quality.

The influence of elevated CO 2 and O 3 concentrations on Scots pine needles: changes in starch and secondary metabolites over three exposure years

“…According to the present study and most earlier studies, O 3 did not have signi®cant eects on needle total phenolic concentrations (Jordan et al 1991;Kainulainen et al 1994Kainulainen et al , 1995aBooker et al 1996). However, higher concentrations of total phenolics (Tingey et al 1976;Kainulainen et al 1994) and some individual phenolic compounds (Kicinski et al 1988;Rosemann et al 1991) were found in conifers exposed to higher O 3 concentrations than used in the present study.…”

Influence of Heavy Metals on the Carbohydrate and Phenolics in Mangrove, Aegiceras corniculatum L., Seedlings

“…Heavy metal induced changes in the phenolic compounds may further affect their functions in plant cells. Phenolic compounds, including tannins, are often involved in responses to different kinds of abiotic and biotic stresses (Rivero 2001;Booker et al 1996;Dixon and Paiva 1995;Yamasaki et al 1995). It is reported that in plant systems, phenolics can act as antioxidants by donating electrons to guaiacol-type peroxidases (GuPXs) for the detoxification of H 2 O 2 produced under stress conditions including heavy metal stress (Sakihama et al 2002).…”

Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

“…It is well documented that chronic as well as acute O 3 exposures impact gene regulation (Ernst 2013;Renaut et al 2009) even though acute episodes could provoke more important changes than chronic ones (Ainsworth et al 2012;Ernst 2013). Furthermore, proteomic analysis confirms the downregulation of a large number of proteins involved in the Calvin-Benson cycle in poplar leaves exposed to chronic O 3 , as well as proteins involved in chloroplastic electron transport (Bohler et al 2007). O 3 also decreases chloroplast size and cell starch content ).…”