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Direct and indirect effects of light on stomata. I. In Scots pine and Sitka spruce
Author(s) -
MORISON J. I. L.,
JARVIS P. G.
Publication year - 1983
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/j.1365-3040.1983.tb01881.x
Subject(s) - scots pine , blue light , red light , botany , far red , conductance , shoot , chemistry , stomatal conductance , photosynthesis , horticulture , biology , pinus <genus> , materials science , physics , optoelectronics , condensed matter physics
. The response of stomatal conductance to broadband blue and red light was measured in whole shoots of Scots pine and Sitka spruce, two species which have low stomatal sensitivity to CO 2 . In Scots pine, blue light was more than three times more effective than red light (on an incident quantum basis) in opening stomata, particularly at low quantum flux densities (<100μmiol m −2 s −1 ). However, the apparent quantum yield of net CO 2 assimilation rate in blue light was only half that in red light. The contrasting effects of red and blue light on conductance and assimilation led to higher intercellular CO 2 concentrations (C i ) in blue light (up to 100 μmol mol −1 higher) than in red light. Similar results were obtained with Sitka spruce shoots, though differences in the effectiveness of red and blue light were less marked. In both species, both red and blue light increased conductance in normal and CO 2 ‐free air, indicating that neither red nor blue light exert effects through changes in C i or mesophyll assimilation. However, decreases in C i caused increases in conductance in both red and blue light, suggesting that these direct effects of light are not wholly independent of CO 2 .