Formation Distribution And Biological Interactions In The Resistance Of Crop Plants

The entire subject has been reviewed in detail several times.32,56,57,65 Recently, a new adsorptive method for the isolation of DIMBOA has been reported.49 The impact of benzoxazinoids on the western corn rootworm (Diabrotica virgifera LeConte) development has been studied.17 The allocation of a hydroxamic acid and biomass during vegetative development of rye has been investigated.27 Effects of benzoxazinoids from maize on survival and fecundity of aphids have been explored.13 DIMBOA...

Evolution And Function Of Secondary Metabolites

Several SM have been used by mankind for thousands of years22,27 as dyes (e.g., indigo, shikonine), flavors (e.g., vanillin, capsaicin, mustard oils), fragrances (e.g., rose oil, lavender oil and other essential oils), stimulants (e.g., caffeine, nicotine, ephedrine), hallucinogens (e.g., morphine, cocaine, mescaline, hyoscyamine, scopolamine, tetrahydrocannabinol), insecticides (e.g., nicotine, piperine, pyrethrin), vertebrate and human poisons (e.g., coniine, strychnine, aconitine) and even...

References

N., Heitholt. J. J., and Duke, S. O., 1994. Physiological effects of cornexistin on Lemma pauscicostata. Pest. Biochem. Phys. 49, 37-52 (2) Armbruster, B. L., Molin, W. T. and Bugg, M. W. 1991. Effects of the herbicide dithiopyr on cell division in wheat root tips. Pestic. Biochem. Physiol. 39, 110-120 (3) Bagchi, G. D., Jain, D. C. and Kumar, S. 1998. The phytotoxic effects of artemisinin and related compounds of Artemisia annua. J. Med. Aromat. Plant Sci. 20, 5-11...

Results And Discussion

Earlier, we analyzed oat roots after BOA incubation of seedlings for at least 24 h and up to 72 h. Two new products were present in the extracts, which were identified as BOA-6-OH and BOA-6-O-glucoside.83 In addition, a third product was found that increased with incubation time. It was slightly more hydrophobic than BOA-6-OH with an UV scan very similar to BOA. The compound was purified, subjected to chemical identification and characterized as BOA-W-glucoside. This product was not found in...

PAs Synthesized By Animals And Their Functions

Although PAs are responsible for poisonous plant toxicoses in livestock throughout the world,32 these compounds are, in general, outstanding deterrents for a large variety of invertebrate and vertebrate herbivores. Pyrrolozidine alkaloids are mutagenic for insects and hepatotoxic and pneumotoxic for mammals, usually exhibiting a delayed toxicity that is characterized by lesions on the liver and other organs. In livestock pyrrolizidine poisoning is asymptomatic at the time of ingestion and is...

Sequestration Of Alkaloids Defense Metabolism And Communication

In a sense, alkaloidal sequestration constitutes the transfer of compounds from the producer to the receiver (predator). In effect, this transfer effectively arms the predator with at least some of the alkaloidal defenses of the ingested plant or animal, probably at little energetic expense to the receiver. Significantly, if a specialist herbivore feeds on an alkaloid-rich plant, it is adapted to tolerate these nitrogen heterocycles which usually render it unpalatable to diverse predators. On...

Food Production On Limited Resources

We have 32.5 billion acres of land in the world. Only 24 or 8 billion acres is potentially suitable for cultivation. The important groups of world food crops (cereal, food legumes, and oilseeds) utilize over 2 billion acres, producing over 1 billion metric tons of food per year (Table I.1). About 70 of the land (23 billion acres) cannot be used for food production. This land is located where it is either too cold, too dry, or too steep, or the soil is too thin (Table 2). About 10 , or 3.2...

Extraction and isolation of diterpenes from P natans

The air-dried and powdered plant material (13 kg) was sequentially and exhaustively extracted with light petroleum, EtOAc and MeOH. The light petroleum extract (66 g) was chromatographed on silica gel eluting with hexane and EtOAc solutions to give fraction A-B. Fraction A eluted with hexane - EtOAc (19 1), was chromatographed using hexane - EtOAc (17 3) as eluent to give pure compounds 8 (57 mg) and 11 (125 mg). Fraction B, eluted with hexane - EtOAc (17 3), was filtered on Sephadex LH-20...

Data analysis

Raw data for all bioassays, except algal test, were analyzed using the Toxcalc Toxicity Data Analysis and Database Software, vers. 5.0 (Tidepool Scientific Software). Point estimations were calculated by concentration response regression using Probit Analysis as first choice and Trimmed Spearman-Karber as second, if Probit was not possible. If the raw data did not allow the respective L(E)C50 to be calculated at the highest tested concentrations, then these values were determined by direct...

Physiological And Biochemical Targets For Alkaloids

Since some alkaloids exhibit great mammalian toxicity (e.g., batrachotoxin, samandarine), it is obvious that these compounds are capable of initiating severe biochemical and physiological lesions. However. it should not be overlooked that toxicological evaluations of most alkaloids have been implemented by in vitro studies in which the alkaloids have been introduced subcutaneously. On the other hand, in nature, in the absence of a venom apparatus, these compounds would be introduced into the...

Pharmacological Properties Of Qa

In addition to toxic and repellent properties, lupin alkaloids have a number of pharmacological activities.15,47,52 Sparteine, lupanine, and other QA exhibit antiarrhythmic properties. Since only sparteine can be isolated easily from broom (Cytisus scoparius) it is the only lupin alkaloid that is commercially available and exploited in medicine as an antiarrhythmic drug. However, about 10 of all patients are unable to metabolize sparteine and suffer from sparteine intoxication. Because of these...

Alkaloids For Defense And Exploitation

Plant alkaloids often demonstrate defensive activity against a wide variety of predators and competitors among which are microorganisms, fungi, viruses, invertebrate and vertebrate herbivores, and plants, including immatures of their own species. Since these alkaloids, termed allelochemicals, have been evolved as deterrents for very different classes of organisms, in plants their production and storage often result in mixtures of structurally diverse alkaloids that are stored at specific sites....

Chemical Defense Based On Alkaloids

Overall, plants are quite capable of defending themselves from diverse microorganisms, herbivores, and other plants. Candidates for this protective role are their allelochemicals, which may possess deterrent repellent or toxic properties for a wide range of competitors.37 Included in the allelochemicals are the alkaloids, which are generally considered to be bitter (e.g., quinine, brucine) and in some cases very toxic (e.g., tetrodotoxin, batrachotoxin). Although at a glance the alkaloids...

Concentration M

Effect of - -usnic acid - - 0.01-100 M on activity of HPPD. The activity of the herbicide sulcotrione was added for comparison - - . Lichens containing usnic acid may exhibit phytotoxic activity. In nature, - -usnic acid may decrease interspecific competition by inhibiting growth of seedlings in the canopy. Since it is primarily an HPPD inhibitor and secondarily inhibits Protox, there may be a decreased chance for resistance in those competing species. Emodin is a naturally occurring...

Methodology

Twenty-five lettuce seeds Lactuca sativa cv. iceberg , onion Allium cepa L. cv. Evergreen Bunching , or a small scoop of bentgrass Agrostis tenuis Sibth were placed on sterile 55-mm dia. filter paper fitted to 60 x 15-mm petri dishes. Filter paper was premoistened with 3 mL of the test solutions. Stock solutions of test compounds were prepared in acetone to obtain final assay concentrations of 100, 33, 10, 3, 1, 0.3, 0.1, and 0.03 uM with volume of carrier solvent being lt 1 in the assay....