Germination, chemistry

The sensitivity of barley to the toxin increases as the stage of germination advances. This may be partially explained by the presence of antifungal agents in the young plant whose activity is reduced with age (8,12). Further progress on the chemistry of this material is reported by Stoessl (14). 

Another very common phytochemical isolated was phytol (3,7,11, 15-tetramethyl-2-hexadecen-l-ol), the diterpenoid alcohol which forms the "tail" of chlorophyll. This compound is nearly insoluble in water, but when applied as a 0.1 mM (0.003 wt. %) solution in 0.1% DMS0 it increased onion germination while decreasing germination in sorghum, wheat, and carrot. The germination effects are significant at only the 95% level, but pretreatment studies are planned as part of other terpene chemistry studies at SRRC and LSI). 

Light absorption is usually quite fast (time scale = 1-10 femtoseconds), and various physical measurements can be used to characterize the properties of intermediates that are formed along the reaction coordinate. This strategy was introduced by Porter who later shared the Nobel Prize in Chemistry with Eigen and Norrish for their germinal contributions to fast reaction kinetics. See Chemical Kinetics... 

Developments in the physical chemistry laboratory since the publication of the germinal text by Schwenz and Moore (/) are categorized and reviewed. The categories examined include modem instrumentation, current topics in chemistry, integrated laboratories, and developments based on chemical education research. New experiments involving traditional instrumentation and topics are include but are not reviewed extensively. 

Tris(i/5-cyclopentadienyl)lanthanides were the first authentic organolanth-anides to be prepared1 and bis(t/5-cyclopentadienyl)lanthanide(II) compounds have played a germinal part in the development of lower oxidation state organolanthanide chemistry.2 These cyclopentadienyls are sources of coordination compounds of structural interest and are reagents for the synthesis of other organolanthanides, for example, bis- and mono(t)5-cyclopentadienyl)lanthanide(III) derivatives.2... 

As mentioned earlier, this group of compounds occurs widely in nature and appears to be non-specific in eliciting activity. Although the chemistry of these compounds has been well defined, the endogenous role of these substances is not. Several of them appear to be inhibitors of seed germination. Since this subject was extensively reviewed by several workers (21, 56, 60), only a minimum of information with a few examples is presented here. 

Fate, G., Chang, M., and Lynn, D. G. 1990. Control of germination in Striga asiatica chemistry of spatial definition. Plant Physiol. 93, 207-207... 

Neither element shows any simple aqueous chemistry in the M(IV) state, as the oxides M02 are insoluble in water at all pH values. Reaction of Sn02 in molten KOH gives the octahedral hydroxanion [Sn(OH)6]2-, in contrast to the normal tetrahedral silicates and germinates, but in parallel with isoelectronic compounds such as Te(OH)6 also found in period 5. Other stannates are mixed oxides without discrete oxoanions (e.g. CaSn03 with the perovskite structure). 

The need for more cost-effective, efficacious, selective, and environmentally safe herbicides is being increased by several current trends in agriculture and agricultural chemistry. The development of microbial toxins or allelochemicals (chemicals produced by plants, which inhibit germination, growth or development of other plants) as herbicides or as sources of new herbicide chemistries promise to help fill this growing need. 

Yu, M.H. 1991. Effects of lead, copper, zinc, and cadmium on growth and soluble sugars in germinating mung bean seeds. Abstracts of the 12th Annual Meeting of the Society of Environmental Toxicology and Chemistry. Seattle, WA, p. 169. 

Seeds can germinate only in fertile soil. Thus, if, as appears likely, cosmic chemistry did play a role in the origin of life on earth, the key question facing us is how frequent, or infrequent, in the universe are the conditions that allowed the products of cosmic chemistry to become fruitfully involved in the generation of living cells ... 

Doblado, R., Frias, J., and Vidal, V.C. 2007. Changes in vitamin C content and antioxidant capacity of raw and germinated cowpea (Vigna sinensis var. carilla) seeds induced by high pressure treatment. Food Chemistry 101 918-923. 

We have described the chemistry of some selected sesquiterpenes which have been classified as phytoallexins. We would to apologize for unintentional omission of any important information in this review, which we tried to make as comprehensive as possible. A variety of synthetic reactions has been used to achieve the total synthesis of these phytoalexin sesquiterpenes. The isolation and biological activity of these sesquiterpenes have been discussed. It is necessary to mention that Takasugi et al.81 have reported for the first time costunolide is an antifungal sesquiterpene which inhibited spore germination of Ceratocystis fimbriata at concentration of 32 pg/ml. Many diterpenes and flavonoides have been also listed as phytoallexins. It is hoped that the research workers would find some useful information in this article. It is safe to predict from discussions in this article that many organic chemists would try to isolate antifungal sesquiterpenes. 

C22H28O6, Mr 388.46, square prisms, mp. 196-197 °C. G., a very bitter-tasting diterpene of the 4a,5/S- cler-odane type from the liverwort Gymnocolea inflata, shows a number of biological activities Thus anti-feedant effects on larvae of Japanese Pieris species, inhibition of root growth (10 -10 Mol) in the cress (Lepidium sativum), and promotion of germination (10 -10" Mol) of wheat seeds have been reported. Ut. J. Hattori Bot. Lab. 39,215 (1975). Zinsmeister Mues (eds.), Bryophytes, their Chemistry and Chemotaxonomy (Proc. Phytochem. Soc. Eur. 29), p. 399,404, Oxford Clarendon Press 1990. 

In the course of basic studies in the germination metabolites of Peganum harmala seeds, it was discovered that the alkaloidal constituents are located in the husk and the kernel yields 20% of oil comparable in its constants and constituents to those of cotton seed oil [9]. However, the economic viability of harmal seeds as a new source of edible oil would largely depend on the utilization of alkaloids from the husk which constitutes 50% of the whole seed and contain ca. 7% of the alkaloidal bases. In view of this fact, intensive studies have been undertaken on the chemistry of the two main alkaloids of harmala, namely harmine, harmidine, and their derivatives, and a whole series of new potentially pharmacophoric derivatives of these bases have been prepared [10]. 

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