Premium
Photosynthesis of Ivy Leaves ( Hedera helix ) after Heat Stress I. CO 2 ‐Gas Exchange and Diffusion Resistances
Author(s) -
BAUER HELMUT
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb01645.x
Subject(s) - hedera helix , photosynthesis , respiration , transpiration , compensation point , botany , heat stress , chemistry , biophysics , chloroplast , diffusion , darkness , horticulture , biology , biochemistry , zoology , thermodynamics , physics , gene
For an analysis of the inhibition of the photosynthetic CO 2 ‐uptake after heat stress attached leaves of Hedera helix L. were heat‐stressed for 30 min at various temperatures. Subsequently their photosynthetic CO 2 ‐uptake, transpiration, respiration in light and darkness, and CO 2 ‐compensation concentration were measured under optimal conditions. After heat stress the stomatal resistance increased only corresponding to the raised CO 2 ‐concentration inside the leaves (due to the reduced CO 2 ‐uptake). The physical resistance between the mesophyll cell walls and the chloroplasts remained unchanged after heat stress. A non‐stomatal inhibition of the CO 2 ‐uptake is indicated by a strong increase of the CO 2 ‐compensation concentration after heat stress. This is hardly due to a stimulation of the respiration in light, as the CO 2 ‐evolution into CO 2 ‐free air in light was even reduced. Therefore, it must be concluded that the photosynthetic process itself is impaired after heat stress.