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The response of carrot ( Daucus carota L.) and onion ( Allium cepa L.) seedlings to mechanical impedance and water stress at sub‐optimal temperatures
Author(s) -
WHALLEY W. R.,
FINCHSAVAGE W. E.,
COPE R. E.,
ROWSE H. R.,
BIRD N. R. A.
Publication year - 1999
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 - 10.1046/j.1365-3040.1999.00412.x
Subject(s) - daucus carota , shoot , mechanical impedance , seedling , horticulture , allium , botany , stress (linguistics) , elongation , biology , chemistry , materials science , electrical impedance , composite material , physics , linguistics , philosophy , quantum mechanics , ultimate tensile strength
The response of pre‐emergent shoots of carrot and onion to mechanical impedance, water stress and suboptimal temperature was studied. We used model laboratory systems in which mechanical impedance and water stress could be varied independently of each other and independently of other complicating factors (e.g. aeration and hydraulic conductivity). Our results showed that mechanical impedance reduced the rate and extent of shoot development in both carrot and onion. Roots of both carrot and onion were less sensitive to mechanical impedance than shoots. The recovery of shoot length following the removal of impedance was studied. The data were used to develop a new model of shoot elongation as a function of mechanical stress, water stress, temperature, shoot length and time. Our results also provide a new insight into the physiology of shoot development in strong soils. We contrast the effect of mechanical impedance on pre‐emergent seedling development in carrot and onion.