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Chunlian Jin, Dan Sun, Chang Wei, Zhenhua Guo, Chunmei Yang, and Fan Li

been reported. In the present study, we analyzed the natural products of G. paniculata stem extract and screened phytochemicals with potential bioactivities by GC-MS. The antioxidative capacity of the medicinal part, the stem, was also evaluated for

Free access

Allen V. Barker

Natural Products from Plants, Second Edition. Leland J. Cseke, Ara Kirakosyan, Peter B. Kaufman, Sara L. Warber, James A. Duke, and Harry A. Brielmann (Editors). 2006. CRC Press Taylor & Francis, Boca Raton, FL. 611 p. $149.95, hardcover. ISBN

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Philipp von Bieberstein, Ya-ming Xu, A.A. Leslie Gunatilaka, and Raphael Gruener

environment. Materials and Methods Seeds of Withania somnifera were obtained from the Natural Product Center (NPC; University of Arizona) stock collection (6 months old, stored at 4 °C). They were germinated in 1-inch Grodan rockwool cubes in a germination

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William J. Bramlage, Zhiguo Ju, and Thomas L. Potter

Diphenylamine (DPA) is applied postharvest to apples and pears to control scald development after storage. Using GC - MS analyses of hexane extracts of fruit surfaces, about 0.1 ug/g of DPA was measured on apples after 7 months of storage, even though no fruit in the storage were treated with DPA. Residues also were present on walls in the storage rooms. There is a report that DPA can be produced in plants. Therefore, fruit of 5 cvs. were harvested in mid-August and at commercial maturity and immediately extracted for measurement. A signal similar to that of DPA was detected in all extracts, but concentrations were too low for positive identification. Results show that presence of DPA residue on stored fruit is not proof that DPA was applied before storage. Extracts from freshly harvested fruit are being concentrated to try to ascertain the identity of the indicated material(s).

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Chien Wang, Korakot Chanjirakul, Shiow Wang, and Jingtair Siriphanich

The effect of naturally occurring volatile compounds on decay and antioxidant activities in fresh-cut papayas (Carica papaya L.) was studied. Exposure to methyl jasmonate (MJ), methyl salicylate (MS) or allyl isothiocyanate (AITC) substantially delayed the onset and reduced the severity of decay during and after storage at 5 °C. Treatment with tea tree oil (TTO) or ethanol (ETOH) was also effective in retarding decay, but to a lesser extent. No beneficial effect was obtained with the use of vinegar vapor. MJ and MS increased oxygen radical absorbance capacity and elevated the activities of several antioxidant enzymes, including glutathione reductase, glutathione peroxidase, guaiacol peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and superoxide dismutase. The nonenzyme components in the ascorbate-glutathione cycle were also increased by MJ and MS treatments, including ascorbate and glutathione. It is possible that MJ and MS treatments enhanced the antioxidant system and increased the resistance of tissue to decay. However, while AITC also suppressed the development of decay in papaya slices, it had little effect on antioxidant levels and antioxidant enzyme activities. Apparently, AITC exerted its effect through different mechanisms. Studies are in progress to determine if AITC inhibits decay directly via its antimicrobial properties.

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Bruce W. Wood, Rufus Chaney, and Mark Crawford

The existence of nickel (Ni) deficiency in certain horticultural crops merits development of fertilizer products suitable for specific niche uses and for correcting or preventing deficiency problems before marketability and yields are affected. The efficacy of satisfying plant nutritional needs for Ni using biomass of Ni hyperaccumulator species was assessed. Aqueous extraction of Alyssum murale (Waldst. & Kit.) biomass yielded a Ni-enriched extract that, upon spray application, corrects and prevents Ni deficiency in pecan [Carya illinoinensis (Wangenh.) K. Koch]. The Ni-Alyssum biomass extract was as effective at correcting or preventing Ni deficiency as was a commercial Ni-sulfate salt. Foliar treatment of pecan with either source at ≥10 mg·L–1 Ni, regardless of source, prevented deficiency symptoms whereas treatment at less than 10 mg·L–1 Ni was only partially effective. Autumn application of Ni to foliage at 100 mg·L–1 Ni during leaf senescence resulted in enough remobilized Ni to prevent expression of morphologically based Ni deficiency symptoms the following spring. The study demonstrates that micronutrient deficiencies are potentially correctable using extracts of metal-accumulating plants.

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Rick A. Boydston, Harold P. Collins, and Steven F. Vaughn

). However, poor efficacy or high cost of many natural products have limited their use. Corn gluten meal is a byproduct from corn wet-milling and has been used to control weeds in turf and other crops ( Liu et al., 1994 ; Liu and Christians, 1997 ; McDade

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Rick A. Boydston, Treva Anderson, and Steven F. Vaughn

Mustard seed meal is a byproduct of mustard (Sinapis alba L.) grown for oil production. Developing new uses for mustard seed meal could increase the profitability of growing mustard. Seed meal of mustard, var. ‘IdaGold’, was applied to the soil surface to evaluate its effect on several common weeds in container-grown ornamentals. Mustard seed meal applied to the soil surface of containers at 113, 225, and 450 g·m−2 reduced the number of annual bluegrass (Poa annua L.) seedlings by 60%, 86%, and 98%, respectively, and the number of common chickweed (Stellaria media L.) seedlings by 61%, 74%, and 73%, respectively, at 8 weeks after treatment (WAT). Mustard seed meal applied to the soil surface after transplanting Rosa L. hybrid, var. ‘Red Sunblaze’, Phlox paniculata L., var. ‘Franz Schubert’, and Coreopsis auriculata L., var. ‘Nana’ did not injure or affect the flowering or growth of ornamentals. In separate experiments, mustard seed meal applied at 225 g·m−2 to the soil surface reduced the number of emerged seedlings and fresh weight of creeping woodsorrel (Oxalis corniculata) 90% and 95%, respectively, at 8 WAT. Mustard seed meal applied at 450 g·m−2 completely prevented woodsorrel emergence at 8 WAT. Mustard seed meal applied postemergence to established liverwort (Marchantia polymorpha L.) at 113, 225, and 450 g·m−2 did not injure container-grown Pulsatilla vulgaris Mill., var. ‘Heiler Hybrids Mixed’ up to 6 WAT and controlled liverwort from 83% to 97% at 6 WAT. Weed suppression with mustard seed meal generally increased as rate increased from 113 to 450 g·m−2. Mustard seed meal may be useful for selective suppression of annual weeds when applied to the soil surface of container-grown transplanted ornamentals.

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Ying Jia, Dianren Xia, and E.S. Louzada

A cDNA coding for a putative terpene synthase (Grtps) was isolated from `Rio Red' grapefruit (Citrus paradisi Macf.) mature fruit by differential display RT-PCR and the corresponding full-length cDNA and genomic clone were subsequently obtained. The isolated cDNA clone was 1644 bp in length encoding a protein of 548 amino acids with a predicted molecular mass of 64 kDa and of pI 5.38. The genomic clone was 3203 bp in length with 6 introns and 7 exons. This Grtps appears to be a sesquiterpene synthase based on molecular weight, genomic organization, and similarity with the other terpene synthases. Both RT-PCR and Northern blot expression analysis indicated that Grtps is not expressed in immature fruits, roots, or leaves, but only in mature fruits. Southern blot analysis of genomic DNA demonstrated that Grtps is one of the members in the family of terpene synthases.

Open access

Lyn A. Gettys, Kyle L. Thayer, and Joseph W. Sigmon

spot treatments. Despite widespread interest in reducing synthetic herbicide use, there is a dearth of information available in the scientific literature regarding the efficacy of natural products such as acetic acid and d-limonene as weed control