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Radicle Elongation of Pea Seedlings as Affected by Oxygen Concentration and Gradients between Shoot and Root 1
Author(s) -
Eavis B. W.,
Taylor H. M.,
Huck M. G.
Publication year - 1971
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1971.00021962006300050034x
Subject(s) - radicle , elongation , shoot , germination , oxygen , coleoptile , botany , horticulture , biology , chemistry , materials science , organic chemistry , metallurgy , ultimate tensile strength
Pea seedlings grown in divided gas‐tight containers were arranged so that O 2 concentration of soil air around the radicles could be varied independently of that around the cotyledons and plumules. When the soil around the radicle tip contained 0.21 atm O 2 , no significant reduction in radicle elongation rate was observed until the gas mixture surrounding the cotyledons was reduced below 0.10 atm partial pressure. Even with O 2 partial pressure at 0 around the cotyledons radicle elongation rate was 50% as high as that of the controls. When O 2 concentration around the radicle was varied, while that around the cotyledons remained at 0.21 atm, the radicle elongation rate at a given O 2 level was markedly reduced. At zero O 2 around the radicle elongation rate was only 20% of normal. It is suggested that a high diffusion impedance between internal gas channels and the relatively undifferentiated tissues near the root tip limits O 2 supply to respiring tissue.