EFFECTS OF NO (+NO2) POLLUTION ON GROWTH, NITRATE REDUCTASE ACTIVITIES AND ASSOCIATED PROTEIN CONTENTS IN GLASSHOUSE LETTUCE GROWN HYDROPONICALLY IN WINTER WITH CO2 ENRICHMENT

Citation
Ca. Hufton et al., EFFECTS OF NO (+NO2) POLLUTION ON GROWTH, NITRATE REDUCTASE ACTIVITIES AND ASSOCIATED PROTEIN CONTENTS IN GLASSHOUSE LETTUCE GROWN HYDROPONICALLY IN WINTER WITH CO2 ENRICHMENT, New phytologist, 133(3), 1996, pp. 495-501
Citations number
29
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
0028646X
Volume
133
Issue
3
Year of publication
1996
Pages
495 - 501
Database
ISI
SICI code
0028-646X(1996)133:3<495:EON(PO>2.0.ZU;2-0
Abstract
Winter hydroponic growth of several lettuce cultivars under glass show ed considerable inhibition (up to 47%) of growth after 6 wk exposure t o concentrations of NO (+ NO2; 450 nl l(-1) in total) typical of emiss ions from propane burners used for direct heating and CO2 enrichment. After a further 4 wk under similar conditions, however, these growth d epressions were replaced by a swing into benefit so that, by harvest, pollutant-exposed lettuces were bigger and had faster assimilation rat es than those growing in clean CO2-enriched air. This adaptation may p artly be explained by enhanced use of NO2-derived N by lettuce leaves, a consequence of increased nitrate reductase (NaR) activities and amo unts of associated NaR proteins, despite adequate nitrate also being a vailable in the hydroponic fluid. Rates of NaR activity in the roots, by contrast, were depressed by NO (+ NO2) pollution. NaR activities we re highest in early afternoon in clean or polluted air but these daily patterns did not coincide with the content of NaR-associated proteins determined by ELISA. Other mechanisms of modulating NaR activity must therefore be responsible.