Growth regulating activity

Of agricultural importance is the plant-growth regulating activity of 6,8-dichloro-2-methyl-3-carboxymethyl-4(3H) quinazolinone which was as potent as 2,4-dichlorophenoxyacetic acid in the Lepidium test. 4-Hydroxy-5,6,7,8-tetrahydroquinazoline has been patented with reference to fungicidal activity. 

G. Cacco and G. Dell Agnola, Plant growth regulator activity of soluble humic complexes. Can. J. Soil Sci, 64 225 (1984). 

Possible Mechanism of Allelopathlc Action of Water-Insoluble Plant Lipids. Many non-polar natural products with germination and growth regulation activities In laboratory tests are In pure form not sufficiently water soluble to account for their allelopathlc activities observed In the field. For this reason the notion exists that sterols and other non-polar plant constituents are not likely to play a role In allelopathlc actions, and It Is generally concluded that the bioactivity data observed In the laboratory are therefore coincidental. 

Furthermore, these compounds were found to possess growth-regulating activity [130,131]. The same compounds were tested for their cytotoxic and cytomutagenic effects. As a result, only weak mutagenic and mytostatic properties of the compounds have been detected [132],... 

Although not containing fluorine, certain acids examined by Wain3 also showed an interesting alternation of biological activity. When the growth-regulating activity of compounds of... 

Figure 18. Plant growth regulating activity of triapenthenol (RSW 0411) and its (+)-R (KTU 1591 inactive) and (-)-S-enan-tiomer (KTU 1592 active) barley.

Table 2. Aliphatic Compounds With Growth Regulating Activity... 

Figure 2, Phenols, aldehydes, carboxylic acids, and other aromatic compounds with growth-regulating activity...

Several terpenoids, particularly those with a lactone moiety, have been examined for plant growth-regulating activity. Incidentally, several of these compounds exhibit anti-tumor and insecticidal activity. They are classified into mono-(CjQ), sesqui-(Ci5), di-(C2Q), tri-(Cgg) and tetraterpenes (C40) Some representative candidates among these classes possessing biological activity are as follows ... 

Figure 8. Diterpenoids with growth-regulating activity...

Table 11. Plant Growth Regulating Activity of Sulfur Compounds...

Several diterpenes present in tobacco plants were evaluated by Cutler (240) for growth-regulating activity in wheat coleop-tile bioassays. Except for isodihydroabienol and B-levantenolide, all of the endogenous tobacco diterpenes showed growth inhibition of the wheat coleoptiles at concentrations of 10 3m or less (Table 14). 

In a search for safer biodegradable plant growth substances that may have potential uses in agriculture, particularly for crop production, our laboratory has developed some new bioassay systems to screen various plants for growth-regulating activity. Our screening efforts resulted in the discovery of both growth promoters and inhibitors. 

When one observes that a certain secondary plant product exerts a growth-regulating activity, obviously the first question that concerns the physiologist is its mode of action. From the foregoing discussion, we know that several diversified organic compounds exhibit different growth phenomena in isolated or intact plant systems. But it is difficult to discuss the mechanism of action of these natural products because of ... 

The first pyridazine for which plant growth regulating activity was patented was maleic hydrazide ( 1). Since the introduction of MH in the late 1940 s, at least four other pyridazines have been developed as herbicides Pyramin by BASF in 1962, Kusakira by Sankyo in 1970, Zorial by Sandoz A. G. in 1971 and pyridate by Chemie Linz in 1976 (2). 

There are some microbial metabolites that show insecticidal or plant-growth regulating activities. Two examples will be given in this section. Both of them have interesting structures. 

A. S. Dimoglo, 1. B. Bersuker, D. P. Popa, and K. 1. Kuchkova, Theor. Eksp. Khim., 5, 590 (1989). Electron-Topological Study of Plant Growth-Regulator Activity in Series of Analogs of the Abscisic Acid. 

Several in vitro tests are suitable for the determination of the growth-regulating activity of hormone-type herbicides, among them the straight growth test of wheat or oat, and the pea curvature test. Both methods yield quantitative results of good reproducibility. The Avena test elaborated by Went cannot be used in this case, but the root growth inhibition test is suitable (Audus, 1949 1951). 

The first detailed investigation of plant growth-regulating activity is linked with the names of Koepfli et al. (1938). On the basis of their experiments with indole and arylalkanoic acids, they established five structural requirements necessary for the biological activity of the molecule. 

The growth-regulating activity of these compounds of different structure indicates at the same time that the molecules of different structure but essentially the same effect interfere with the biochemical processes at different phases of the growth process. 

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