Erschienen in:
Zeitschrift für Pflanzenernährung und Bodenkunde, 152 (1989) 2, Seite 247-254
Sprache:
Englisch
DOI:
10.1002/jpln.19891520217
ISSN:
0044-3263
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The phytohormones indole acetic acid (IAA), abscisic acid (ABA), isopentenyladenosine (iPA), dihydrozeatin riboside (DHZR), and zeatinriboside (ZR) were determined quantitatively using monoclonal antibodies by an enzyme immunoassay in the following samples: a) culture filtrates of known bacterial species, growing naturally in close, loose or without contact with higher plants; b) culture filtrates of heterogeneous populations of microorganisms, isolated from the rhizoplane and rhizosphere of maize as well as from root‐free soil; c) sterile and nonsterile maize root exudates; d) in the rhizosphere of field‐grown maize plants and in soil fractions distant from the roots (bulk soil).</jats:p><jats:p>ABA was not detected in the culture filtrates of bacteria and ZR was not found in bulk soil and rhizosphere soil of field‐grown maize. All phytohormones were present in the other samples analyzed. Bacterial cultures with cell concentrations roughly equal to those in the rhizosphere of field‐grown maize may produce under optimal laboratory conditions phytohormone concentrations comparable to those measured in the rhizosphere of field‐grown maize. During the whole vegetation period there was a steep phytohormone gradient in the first centimeter of soil around a maize root in the field. Inoculation of maize seedlings growing in nutrient solution with rhizosphere bacteria resulted in a synergistic increase in phytohormone concentration in comparison to the sum of hormone production by sterile plant roots and by bacteria cultures.</jats:p><jats:p>Using regression analysis, the relationship between phytohormone concentration changes in the rhizosphere and different morphological characteristics of the maize plant were shown to be highly significant.</jats:p>