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Effects of O 3 on the stomatal behaviour of Egyptian varieties of radish (Raphanus sativus L. cv. Baladey) and turnip (Brassica rapa L. cv. Sultani)
Author(s) -
HASSAN I. A.,
ASHMORE M. R.,
BELL J. N. B.
Publication year - 1994
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.1469-8137.1994.tb04008.x
Subject(s) - raphanus , brassica rapa , brassica , biology , stomatal density , botany , horticulture , brassica oleracea , brassicaceae , photosynthesis
summary The effects of O 2 (80 nl 1 −1 ) on the photosynthetic rate (A) and stormatal conductance (g) of Egyptian varieties of radish (Raphanus sativus L. ev. Baladey) and turnip (Brassica rapa L. ev. Sultani) were examined. Exposure to O 3 decreased A in both species, while gs was increased in radish and decreased in turnip. The effect of different concentrations of O 3 , (50, 100, 150 nl l −1 on radish was examined and it was found that A decreased, while g, increased, with increasing concentrations of O 3 . Scanning electron microscopy (SEM) of fumigated leaves showed that the increase in g s in radish resulted from the collapse of epidermal cells. Counts of the percentage of stomata which were fully open demonstrated that 80 nl 1 −1 O 3 caused an increase of 18% in radish and a decrease of 14% in turnip. The proportion of opened stomata was found to increase with increasing O 3 concentration in radish.