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THE PARTITIONING OF RESISTANCES TO PHOTOSYNTHETIC CO 2 UPTAKE IN THE LEAF
Author(s) -
KOLLER DOV
Publication year - 1970
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.1469-8137.1970.tb02476.x
Subject(s) - photosynthesis , transpiration , botany , drought resistance , diffusion , biology , horticulture , chemistry , physics , thermodynamics
S ummary A theoretical analysis is presented of the partitioning of overall resistance to photosynthetic CO 2 uptake in the leaf. This is based on the existence of a resistance to gaseous diffusion between the upper and lower layers of the chlorenchyma ( R i ). It takes into account the anisolaterality of the leaf with respect to resistance to diffusion ( R w ) through the upper and lower surfaces, and with respect to the (residual) resistance to CO 2 uptake and fixation ( R m , the ‘mesophyll resistance’) in the upper and lower chlorenchyma. When R i exists in conjunction with epidermal anisolaterality, mesophyll resistance of the whole leaf ( R ¯ m ) is over‐estimated by subtracting the diffusion component resistance ( R ¯ w ) from the total resistance to CO 2 uptake ( R ). This over‐estimation increases with epidermal and mesophyll anisolaterality, as well as with increase in R i and R ¯ w , but decreases as R ¯ m becomes relatively greater. A method is presented and discussed, by which R i and the R m values of the two sides of the leaf can be simultaneously estimated, using simultaneous measurement of their transpiration and photosynthesis and of diffusion porometry through the leaf.