Studies on octylphenoxy surfactants

IX. Effect of oxyethylene chain length on GA₃ absorption by sour cherry leaves

authored by

Moritz Knoche, Martin J. Bukovac

Abstract

The effect of a homologous series of octylphenoxy surfactants, α-[4-(1,1,3,3-tetramethylbutyl)phenyl]-ω-hydroxypoly-(oxy-1,2-ethanediyl), condensed with 5, 7-8, 9-10, 16, and 30 oxyethylene (EO) units on enhancement of gibberellic acid (GA₃) absorption by leaves of Prunus cerasus cv. Montmorency was studied. Increasing EO chain length (5-30 EO) increased surface tension (27.5-35.3 mN m^-1) and contact angles on adaxial (21-36°) and abaxial (28-49°) leaf surfaces. With increasing EO content, the form of GA₃ deposits from droplets on the leaf surface changed from an annulus shape (5 and 7-8 EO) to globular forms covering increasingly smaller interface areas (9-10 to 30 EO). The surfactants increased GA₃ uptake, the magnitude decreased with an increase in oxyethylene chain length. Similar trends were found for both the adaxial and abaxial surfaces. Penetration through the abaxial surface was linearly related to the logarithm of the oxyethylene content of the surfactant molecule (r²=0.934^**) and to the hydrophilic: lipophilic balance (r²=0.926^**). Absorption by the abaxial surface was approximately one order of magnitude greater than by the adaxial surface.

External Organisation(s)

Michigan State University (MSU)

Type

Article

Journal

Journal of plant growth regulation

Volume

10

Pages

173-177

No. of pages

5

ISSN

0721-7595

Publication date

12.1991

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Agronomy and Crop Science, Plant Science

Electronic version(s)

https://doi.org/10.1007/BF02279330 (Access: Closed)