Seed germinability

D. J. Reed, E. N. Dost, and C. H. Want, "Inorganic Eluoride Propellant Oxidizers, Vol. 1 Their Effects Upon Seed Germination and Plant... 

GibberelHc acid is also used successfliUy in rice culture to promote seed germination and the growth of semidwarf varieties. The treated seed can be planted deeper than normal. In addition, the sprouting seedlings are much taller than the untreated ones they compete weU against weeds. The material is sold under the trade name Release. 

The various fumigants often exhibit considerable specificity toward insect pests, as shown in Table 8. The proper choice for any control operation is determined not only by the effectiveness of the gas but by cost safety to humans, animals, and plants flammabdity penetratabdity effect on seed germination and reactivity with furnishings. The fumigants may be used individually or in combination. Carbon tetrachloride has been incorporated with carbon disulfide, ethylene dichloride, or ethylene dibromide to decrease flammability, and carbon dioxide is used with ethylene oxide for the same purpose. 

In addition to inhibitory chemicals which enter the plant from the external environment, many endogenous inhibitors appear to function as regulators of seed germination and plant growth and development. The interrelationships between endogenous inhibitors and growth promoters such as the auxins, gibberellins, and kinins remain to be elucidated. 

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-... 

Thiourea and allylthiourea (20), D-xylulose (22), sodium diethyldithiocarbamate, L-methionine, and -propyl-di- -propylthiol-carbamate (163), 12 6-(substituted) purines (166), and two coumarin derivatives (164) have been found to promote Striga seed germination. None of these materials, however, appear to be constituents of the natural stimulant preparations. 

Senaratna, T. McKenzie, B.D. (1986). Loss of desiccation tolerance during seed germination A free radical mechanism of injury. In Membranes, Metabolism and Dry Organisms, ed. A.C. Leopold, pp. 85-101. Ithaca, N.Y. Comstock Publishing Associates. 

Thompson, P. A. 1973. Seed germination in relation to ecological and geographical distribution. 

M. J. Krogmeier and J. M. Bremner, Effects of phenolic acids on seed germination and. seedling growth in soil. Biol. Fertil. Soil ftll6 (1989). 

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). 

In our efforts to detect and isolate the allelcpathic agents from tall fescue and several other grass species, we extracted the detached plant material with water and/or organic solvents. Either solvent extraction method yielded extracts that were inhibitory to the seed germination and seedling growth in our bioassay systems. 

Effects of Sesquiterpene Lactones on Seed Germination. Sesquiterpene lactones are common constituents of the Asteraceae but are also found in other angiosperm families and in certain liverworts (31,32). These highly bitter substances exhibit a wide spectrum of biological activities (J 3) which include cytotoxicity, anti-tumor, anti-microbial, insecticidal (34) and molluscicidal (35) properties. Furthermore, they are known causes for livestock poisoning and contact dermatitis in humans (33). Structure-activity relationship studies on sesquiterpene lactones have demonstrated that biological activity frequently depend on the presence of the cr... 

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... 

Seed germination. Germination of wild mustard seeds with a dormancy level of about 50 percent was stimulated after 10 days to... 

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