ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The effect of acute O3 exposure (5 h at 150 ppb) on photosynthetic electron transport and the thylakoid polypeptide pattern has been studied in 2-month-old cuttings of two poplar clones (Populus deltoides×maximowiczii clone Eridano and P.×euramericana clone I-214), known for their differential response to O3 in terms of visible symptoms. The more sensitive Eridano developed severe blackish bifacial necrosis concentrated in the interveinal areas of the basal and intermediate leaves, while in the less sensitive I-214 clone, visible symptoms were slight or entirely absent. A generalized, significant decrease in leaf pigment content was shown by both of the stressed clones, although the decline in β-carotene content was much more marked in Eridano than in I-214. Activation of the xanthophyll cycle was not detected in either clone. In both clones, immunoblot analysis of the thylakoid proteins showed a decrease in the levels of all the PSII polypeptides tested following O3 exposure, whereas the PsaA/B protein in the PSI core was more severely affected in Eridano than in I-214. No changes in the chloroplast structure could be seen on electron microscopic study in either clone. The only visible difference was a great accumulation of starch grains in Eridano. All of these results suggest that O3 exposure induces alterations in the photosynthetic apparatus in both poplar clones, Eridano being affected to a greater extent than I-214.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1399-3054.2000.110206.x
