Stimulation of ethylene production and gas-space (aerenchyma) formation in adventitious roots of Zea mays L. by small partial pressures of oxygen

Adventitious roots of two to four-weekold intact plants of Zea mays L

M. B. Jackson

2004

Scholarcy highlights

  • Adventitious roots of two to four-weekold intact plants of Zea mays L
  • LG11) were shorter but less dense after extending into stagnant, non-aerated nutrient solution than into solution continuously aerated with air
  • When oxygen partial pressures similar to those found in non-aerated solutions were applied for 7 d to root systems growing in vigorously bubbled solutions, the volume of gas-space in the cortex was increased several fold. This stimulation of aerenchyma was associated with faster ethylene production by 45-mm-long apical root segments
  • The effect of AVG was reversible by concomitant applications of 1-aminocyclopropane-1-carboxylic acid, an immediate precursor of ethylene
  • Treating roots with only 1 kPa oxygen stimulated ethylene production but failed to promote gas-space formation. These severely oxygen-deficient roots seemed insensitive to the ethylene produced since a supplement of exogeneous ethylene that promoted aerenchyma development in nutrient solution aerated with air failed to do so in nutrient solution supplied with 1 kPa oxygen
  • Both ethylene production and aerenchyma formation were almost completely halted when roots were exposed to nutrient solutions devoid of oxygen
  • Both processes require oxygen and are stimulated by oxygen-deficient surroundings in the 3-to 12-kPa range of oxygen partial pressures when compared with rates observed in air

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