Growth Modifiers, Antibiotics and Their Effects on Plant Growth

Abstract

These experiments were undertaken to confirm the antibiotic stimulation of plant growth under rigidly controlled conditions, to compare several antibiotics on the basis of their ability to stimulate growth, and to study the mechanism of this stimulatory action. Lemna minor, one of the duckweeds, was used as the test object because it can be rendered aseptic and grown under aseptic conditions easily. Its uniform growth, relatively rapid rate of growth, ability to grow on a chemically defined medium, and small size make it an ideal experimental plant. Not all antibiotics stimulate plant growth. Penicillin G and Bacitracin were outstanding in their ability to stimulate growth under test conditions.In general, most other antibiotics stimulated or inhibited growth according to the concentration tested, the length of the growth period, or the specific conditions of the experiment. The results of this investigation have suggested several hypotheses as to the mechanism of stimulatory action. It is hoped that experiments currently in progress will determine which of these hypotheses is correct. Representativesof most groups

Penicillium fungi from Picea glehnii seeds protect the seedlings from damping‐off

“…Patulin (1) and citrinin (2) have already been reported to be phytotoxic (Wang, 1948;Nickell & Finlay, 1954 Truelove, 1972;Damodaran et al, 1975). When we discuss the role of the isolated Penicillium species in protecting P. glehnii seedlings from the damping-off caused by P. vexans, we need to examine whether or not the compounds produced by those isolated Penicillium species are phytotoxic to the P. glehnii seedling.…”

“…, 1943; Katzman et al. , 1944; Robinson & Park, 1966), have been reported as phytotoxic compounds (Wang, 1948; Nickell & Finlay, 1954; White & Truelove, 1972; Damodaran et al. , 1975).…”

“…Previously, we screened for microorganisms on the surface of seeds that produced antifungal compounds against a damping-off fungus, Pythium vexans , and isolated three Penicillium species producing peculiar antifungal compounds, patulin, citrinin and palitantin (Yamaji et al , 1999). Patulin and citrinin (Anslow et al , 1943;Katzman et al , 1944;Robinson & Park, 1966), have been reported as phytotoxic compounds (Wang, 1948;Nickell & Finlay, 1954;White & Truelove, 1972;Damodaran et al , 1975).…”

Experimental Control of Flowering in Lemna. III. A Relationship between Medium Composition and the Opposite Photoperiodic Responses of L. perpusilla 6746 and L. gibba G3

“…It has been reported (Nickell and Finlay, 1954;Nickell, personal communication) that Lemna cultures excrete organic substances into the medium, and it is well-known that root cultures do so (Burstrom, 1953). Together with the observed pH-dependence of the "aged" medium activity, this information makes it reasonable to ascribe the "aged" medium effect to the presence of 1 or more active chelating agentsorganic acids or amino acids, for example.…”

The effects of aflatoxin B1, citrinin, and ochratoxin A on amino acid uptake and incorporation by cucumber

“…Working with plant tissues, Iyengar and Starkey (6) were able to show both an antagonism and a synergism between the toxin and indole acetic acid (IAA). At concentrations above 1 ppm, it is toxic to Lemna minor, but at a concentration of 1 ppm it has been shown to stimulate Lemna growth (13). Rao and Thirumalacher (15) were able to control black rot of cabbage, a bacterial disease caused by Xanthomonas campestris (Pam) Dows., by treating cabbage seed with citrinin.…”