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Effects of CO 2 concentration and irradiance on the stomatal behaviour of maize, barley and sunflower plants in the field
Author(s) -
LOUWERSE W.
Publication year - 1980
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11586830
Subject(s) - transpiration , sunflower , stomatal conductance , irradiance , photosynthesis , agronomy , chemistry , helianthus annuus , horticulture , botany , biology , physics , quantum mechanics
Maize, barley and sunflower plants were grown in the field, well supplied with water and nutrients. During growth, net CO 2 exchange and transpiration of the crops at varying ambient CO 2 concentrations and irradiance were determined by infra‐red gas analysis. In maize the net photosynthetic rate (P n ) was linearly related to the irradiance ( I ) and independent of the ambient CO 2 concentration ( C a ). The transpiration rate ( E T ) was also linearly related to I but decreased strongly with increasing C a . In sunflower and barley P n increased and E T decreased with increasing C a . A mean stomatal conductance and intercellular CO 2 concentration ( C i ) were calculated. In all three species the internal CO 2 concentration was independent of the irradiance. In maize it was also independent of C a , but in sunflower and barley C i was proportional to C a with a ratio of 0.6. It is concluded that differences in stomatal behaviour are only partly species‐specific and depend mainly on growing conditions. The importance of stomatal regulation for crop growth under conditions of water shortage and CO 2 depletion is discussed.