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ABSORPTION OF NITROGEN DIOXIDE BY SUNFLOWER PLANTS GROWN AT VARIOUS LEVELS OF NITRATE
Author(s) -
OKANO K.,
TOTSUKA T.
Publication year - 1986
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1986.tb00831.x
Subject(s) - nitrate , sunflower , helianthus annuus , chemistry , nitrite , nitrogen , nitrate reductase , nitrogen dioxide , absorption (acoustics) , horticulture , dilution , agronomy , biology , materials science , organic chemistry , composite material , physics , thermodynamics
S ummary The effect of varied levels of nitrate on the absorption of atmospheric nitrogen dioxide (NO 2 ) by sunflower ( Helianthus annus L.) plants was investigated by using a 15 N dilution method. Growth of the plants was greatest at 5 mM nitrate, with less growth at 15 mM nitrate and a considerable reduction at zero nitrate. The total amount of NO 2 ‐nitrogen absorbed by the plant depended on the plant size and total leaf area. Nitrate supply did not influence the rate of absorption of NO 2 by the plants when exposed to 0.3 μl l −1 NO 2 . On the contrary, when the plants were exposed to 2.0 μl l −1 NO 2 , the absorption rate was significantly lower for the plants grown at zero nitrate compared with those grown at 5 or 15 mM nitrate. The lower rate of NO 2 absorption in the nitrate‐deficient plants was not due to the changes in stomatal resistance or stomatal density of the leaves, but could have been due to an increase in mesophyll resistance resulting from accumulation of high levels of nitrite in the leaf tissues. Nitrogen dioxide at 0.3 μl l −1 exerted a nutritional effect on the nitrate‐deficient plants, while NO 2 at 2.0 μl l −1 acted as a toxic air pollutant on the plants at all the levels of nitrate supplied.