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Herbicidal activity of 4‐chloroindoleacetic acid and other auxins on pea, barley and mustard
Author(s) -
Engvild Kjeld C.
Publication year - 1996
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1996.tb00222.x
Subject(s) - auxin , pisum , white mustard , hordeum vulgare , sativum , biology , sinapis , 2,4 dichlorophenoxyacetic acid , mcpa , botany , chemistry , biochemistry , brassica , pesticide , poaceae , agronomy , gene
The natural auxins, 4‐chloroindoleacetic acid and its methyl ester have strong herbicidal effects on pea, Pisum sativum , a plant in which they occur naturally. The standard herbicide, 2,4‐dichlorophenoxyacetic acid (2,4‐D) is only 5 times more effective than 4‐chloroindoleacetic acid. The I 50 , the dose inhibiting yield by 50%, for 4‐chloroindoleacetic acid and its methyl ester is 0.5 kg ha −1 or 15 mg kg −1 fresh weight, close to the concentration of 4‐chloroindoleacetic acid methyl ester in maturing pea seeds. Naphthaleneacetic acid and indoleacetic acid are also inhibitory, but at much higher concentrations. In its inhibiting effect on white mustard, Sinapis alba , 4‐chloroindoleacetic acid approximates that of 2,4‐D, whereas in barley, Hordeum vulgare , it is a stronger herbicide than 2,4‐D. All auxins tested killed white mustard at low doses, but none killed barley. Both 4‐chloroindoleacetic acid and 2,4‐D killed pea. The chloroindole auxins of pea may be the hypothetic death hormones or senescence factors that are secreted from the developing seeds into the parent plant which is strongly inhibited or killed and from which the nutrients are mobilized and translocated to the seeds. The action mechanism of auxin type herbicides may be to simulate the action of endogenous herbicides.