Seed germination inhibition

Figure 4. Correlation of seed germination inhibition (x-x) with GC peak size of compound RT = 29.5 min (o-o) of fractions 68-73 of the liquid chromatography (see Figure 3). (Reproduced with permission from reference 6. Copyright 1982 Verlag der Zeitschrift fur Naturforschung.)...

During the search for a lettuce seed germination inhibiting substance from a species of lum (unidentified) a novel com-... 

Some bithienyl and terthienyl derivatives display biological activities including antifungal, nematocidal, and seed germination inhibition. The Stille reaction is regarded as the method of choice for the preparation of these thiophenes. For example, the union of 5-iodo-2-thiophenecarboxaldehyde and 2-tributylstannylthiophene furnished 5-(2 -thienyl)-2-thiophenecarboxaldehyde (209) [96]. In addition, terthienyl and bithienyl derivatives have been synthesized using 3,4-dinitro-2,5-dibromothiophene [143] and... 

Phytotoxicity is expressed as a del of seed germination, inhibition of plant growth or aity adverse effect on plants caused by specific substances (phytotoxines) or growing conditions. 

Bradow, J.M. W.J. Connick, Jr. 1988b. Seed-germination inhibition by volatile alcohols and other compounds associated with Amaranthus palmeri residues. J. Chem. Ecol. 14 1633-1648. 

Various assay methods have been used to detect the presence of inhibitory substances. These include some of the classical tests used by investigators of growth-promoting substances—i.e., the various Avena coleoptile assays which utilize intact, decapitated, or isolated cylinders and the split pea stem test. Effects on seed germination and seedling shoot or root growth and development have also been measured in addition to other visible expressions of inhibition. Details of many of these tests have been compiled by Mitchell et al. (99). Tests have been carried out in Petri dishes, with various solution culture techniques, and by sand and soil culture. Effects so measured may or may not be similar to those obtained under field situations— i.e., the establishment of inhibition under controlled conditions pro-... 

Gressel and Holm 56) attributed delayed germination of tomato seed and inhibited elongation of the seedling to unidentified ninhydrin-positive compounds present in the seed and foliage of Abutilon theophrasti. 

Aliphatic compounds Several water-soluble simple organic acids and alcohols are cannon plant and soil constituents. They include methanol, ethanol, n-propanol and butanol (40), and crotonic, oxalic, formic, butyric, lactic, acetic and succinic acids (41, 42), all of which inhibit seed germination or plant growth. Under aerobic conditions, however, aliphalic acids are metabolized in the soil and therefore, should not be considered a major source of allelopathic activity (40). 

Psilotin (R 0-D-glucose) Psilotinin (R=H) o o / o Psilotun nudum and IVesiperis tannensis Inhibits seed germination and seedling growth... 

Protoanemonin Several Ranunculacea sp. Inhibits seed germination... 

Leaf leachates and decanposition products Inhibitors fran leaves may be washed into the soil or compounds from leachates may further decompose into toxic products which inhibit seed germination and prevent seedling establishment (46). 

Calein A (24) which contains one a, 0-unsaturated ketone, ester and lactone moiety has only minor effects on most seed germinations but strongly inhibits Palmer amaranth (75%) at the 0.05 mM level. 

The dlterpene lactone 17-acetoxyacanthoaustralide (25) has minor effects, showing promotion of clover (112%), cucumber (109%) and Palmer amaranth (111%) and inhibition of carrot germination (91%). The flavonoid artemetin (26) at 0.05 mM concentrations slightly affects onion (93%), oat (91%) and promotes seed germinations In carrot (116%) and Palmer amaranth (113%). In closing, it is noteworthy to point out that lettuce and cress are not significantly affected by all ten sesquiterpene lactones as well as the dlterpene (25) and artemetin (26). 

Seed germination. Tests for allelochemical Inhibition of wild mustard [Brasslca kaber (DC.) L.C. Wheeler var. plnnatlflda (Stokes) L.C. Wheeler] seed germination were made according to the methods of Leather (3). Germination of white clover (Trlfollum... 

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