Ferrero, Aldo

Tesio, Franco

Vidotto, Francesco

Weston, L.

English

Institutional Research Information System University of Turin

plants stayed highly limited. Efforts to add new specieswith allellopathic effect or residual effect and to extent therange of effected plants have been continued mainly incontrolled conditions. These studies included tree parts aswell as herbs. Several species were suggested to use weedcontrol in corn. Allelopathic chemicals such as juglon anddopa investigated for their effect on plants in addition towater or oil extracts of plants and plant residues. Alfalfahas been suggested as an allelopathic crop to control someweeds such as Acroptilon repens and Artemisia vulgaris. Invitro experiments were carried out to find out the possiblecrops that can succeed alfalfa without any chemical siteeffect of alfalfa. The allelopathic relations betweenArtemisia vulgaris and alfalfa were studied. The aim ofstudies is not only controlling weeds in crops but alsounderstanding weed interference. Although experts whoattended the National allelopathy workshop agreed oncollaboration and a national network, no visible attempthas been made. However, allelopathy studies have beengoing on.381. Phytotoxic Mechanisms of L-DOPA and M-Tyrosine.Hiroshi Matsumoto1, Mayumi Hachinohe1; 1University ofTsukuba, Tsukuba, Ibaraki, JapanL-DOPA (3.4-dihydroxyphenylalanine) is one of well-known allelochemicals that inhibits plant growth. In thesurvey of phytotoxicity among structurally related com-pounds with L-DOPA, we found that m-tyrosine hascomparable phytotoxic potential with L-DOPA (Shirato etal., 2005). m-Tyrosine was also identified as the majorcomponent of phytotoxicity in fine fescue grasses (Bertin etal., 2007).L-DOPA and m-tyrosine (10-4 M) inhibited the growthof lettuce root to 20% of non-treated control at 5 DAT.However, m-tyrosine did not show selectivity betweenlettuce and barnyardgrass that was observed in L-DOPAtreatment. Our previous study showed that L-DOPAincreased reactive oxygen species generated from themetabolic pathway from L-DOPA to melanin. Hugeaccumulation of melanin and typical oxidative damagewere observed in L-DOPA -treated lettuce. m-Tyrosinealso increased lipid peroxide formation in lettuce, butincrease of melanin formation was less than that by L-DOPA. Exogenously-applied antioxidants, ascorbic acidand a-tocopherol, alleviated the phytotoxicity of L-DOPAbut did not that of m-tyrosine. However, phenylalaninealleviated the phytotoxicity of m-tyrosine in roots oflettuce and rice. In a proteomics anaylsis, phenylalanineammonia-lyase (PAL) was identified as one of responsiveproteins in m-tyrosine treated rice. The amount of PALexpression decreased in m-tyrosine treatment, but did notdecrease in m-tyrosine plus phenylalanine treatment.These results suggest that phytotoxic action andmechanism are different between m-tyrosine and L-DOPA. The decrease of PAL expression might be involvedin the phytotoxic mechanism of m-tyrosine.382. Effect of Aqueous Extract from Flaveria bidentis onPlant Germination. Xiangju Li1, Miru Zhang1, YongjunLi1; 1Institute of Plant Protection, Chinese Academy ofAgricultural Sciences, Beijing, China (Peoples Republic of)Flaveria bidentis is an invasive plant recently found innorth China. In order to investigate the invasive mecha-nism which is very important to the spread and ecologicalrenovation of invasive plants, experiments were conductedin Petri dishes under laboratory conditions to study theeffect of aqueous extracts of F. bidentis on plantgermination and radical elongation. Among the 30 selectedreceiver plants, 29 species were inhibited in seed germina-tion and 28 species were inhibited in radical length tovarying degree in the extracts of F. bidentis at theconcentration of 0.1g dry weight/mL, however, 2 specieswere stimulated in radical length in the extracts. There wasa strong correlation between extract concentration andincreased inhibition in test species. A gradually decrease ofseed germination and radical length of E. crus-galli and B.napus was observed with increasing the concentration ofthe extracts. Radical length of B. napus was inhibited by15.39% to 89.74% when extract concentration was 0.01 to0.08g dry weight/mL and no germinated seed of B. napuswas observed when extract concentration was 0.10g dryweight/mL.Seed germination and radical length of E. crus-galli and B. napus were inhibited more by extracts frommature plants than that from young plants of F. bidentisand more by extracts from leaves than that from stems,and roots was the last. These results indicated that F.bidentis may affect the germination and early growth ofplants growing in the same ecosystem by releasingallelochemicals and the substances may accumulate andreduce the biodiversity in the invaded land if F. bidentisgrows in high density.383. Identification of Allelopathic Compounds from Heli-anthus tuberosus L. Leaves. Franco Tesio1, Leslie Weston2,Francesco Vidotto1, Aldo Ferrero1; 1Universita` di Torino,Grugliasco, Torino, Italy; 2Environmentals, L.L.C. Con-sulting for the Landscape, Turf, and Ornamentals Indus-tries, Ithaca, NY, United States of AmericaAllelopathy has been largely studied for several Com-positae species, and a significant amount of information isavailable in particular on Helianthus annuus L.. Only a fewstudies, however, have considered the related perennialspecies H. tuberosus L. which is cultivated in Europe asvegetable and for industrial uses, and behaving as a weedin summer annual crops. The objectives of this study wereto assess the allelopathic effects of different populations ofH. tuberosus on germination and seedling growth of some156cultivated and weed species and to identify the allelochem-icals responsible for the inhibitory activity. The release ofthe allelopathic compounds during the natural degrada-tion of residues was simulated with a bioassay usingParker plates, filled with 150 g of soil and sand mixture,and different amounts ofH. tuberosus dry leaf tissue (0.5, 1and 1.5 g per plate). H. tuberosus rough material camefrom 4 cultivars (Fuseau, Red Fuseau, Stampede, HybridStampede) and a weedy biotype (Italian). Inhibition of drytissue was assessed in terms of seed germination, and shootand root elongation of Digitaria sanguinalis, Echinochloacrus-galli, Lactuca sativa, and Lycopersicon esculentum.Fuseau resulted the most toxic cultivar on germination andgrowth of D. sanguinalis, showing an important inhibitoryeffect already at the lowest rate (0.5 g). None of thecultivars tested significantly inhibited the germination ofE. crus-galli, even though root elongation was stronglyaffected at 1.5 g by almost all cultivars. Both shoot androot length of L. sativa was strongly affected by allcultivars. Root growth, in particular, was reduced formore than 78% at 1.5 g. On average, L. esculentumresulted the most sensitive indicator species, as nogermination was observed, starting from the smallestamount of residues. Among the tested populations, thestrongest inhibition activity, was recorded in the cultivarsFuseau and Stampede and in the biotype Italian.Powdered leaf tissues of these populations were used forthe solvent extraction, with either hexane, ethyl ether, orethyl acetate. Toxicity of the extracts on germination andshoot and root elongation of L. sativa was assessed in Petridishes (5 cm). Ethyl ether fraction from the cultivarFuseau was, on average, the most toxic. About 90% ofshoot length reduction was achievable with only 0.21 lg/dish of extract. This fraction was analyzed with liquid-mass chromatography by detecting phenolic compounds.Salicylic acid was detected in all fractions tested at anaverage concentration of 10.16 mg/kg. Few amounts of ocoumarinic and p coumarinic acids were also found. Thephenols detected in this study are often associated withallelopathic behavior in Compositae weed species. Alle-lopathy may be advantageous to H. tuberosus cultivation,as it potentially reduces the sensitivity of this species toweed, theoretically allowing a reduction of inputs requiredfor weed control, even in the successive crop, due to therelease of phenolic compounds. On the other hand,allelopathic activity of H. tuberosus residues may beunfavorable to the sensitive crops cultivated after H.tuberosus or planted in an area infested by this species384. Studies on Allelopathic Physiobiochemical Character-istics of Solidago canadensis L.. Qiong-xia Guo1, Li-huaShen2, Zhen Huang3; 1Fujian Entry-Exit Inspection andQurantine Bureau, Fuzhou, Fujian, China (PeoplesRepublic of); 2Key Laboratory of Biopesticide andChemical Biology, FAFU, Fuzhou, Fujian, China (Peo-ples Republic of); 3Graduate School of Hainan University,Haikou, China (Peoples Republic of)The study on the physiobiochemical process and itsmechanism of weed allelopathy has now become mainissue in the world. For this purpose, wheat as receiverplant were cultured in 1/2 Hoagland nutrient solutionwhich included extracts of allelopathic weed Solidagocanadensis L. and non-allelopathic weed Solidago decur-rens Lour., respectively. And then physiobiochemicalapproach was employed to get first insight into themechanism of allelopathy in Solidago canadensis L.The results were summarized as follows: the allelopathyof Solidago canadensis L. significantly decreased theactivities of protective enzymes such as SOD, POD andCAT in wheat, coupling with the increase of free radicalcontents and serious membrane lipid peroxidation. It wasalso indicated that root activity in wheat was negativelyaffected, in turn decreased the uptake of nutrients(N, P, Kelements) from the enviroment. The result also indicatedthat the extracts of Solidago canadensis L. reduced thechlorophyll concentration in wheat, then the weakphotosynthesis was the result, consequently leading todecreased dry matter weight of wheat seedlings. Thereverse was true in non-allelopathic weed Solidagodecurrens Lour. The findings suggested that Solidagocanadensis L. possess a strong allelopathic biologicalactivity and exhibits strong inhibition of wheat.385. Allelopathic Potential of Sunflower Plant (Helianthusannus L.) on Soil Metals and its Leaves Extracts onPhysiology of Wheat (Triticum aestivum L.) Seedling. JavedKamal1, Asghari Bano1, Muhammad Riaz1; 1Quaid-I-Azam University, Islamabad, PakistanThe allelopathic potential of cultivar Sunflower varietycv- Hysun 38 (Helianthus annus L.) was studied and itseffect on metals and leaf aquous extract of sunflower atdifferent concentrations were applied to determine theireffect on wheat two varieties cv.Margalla 99 and cv.Chak-wall 97 seed germination rate and hormonal analysis underlabortary conditions in petridishes were conducted.Commonly observed action of allelochemicals are inhibi-tion of seed germination and abnormalties of seedlingdevelopment. Catabolism of storage reserves and energyproduction are most important factors ensuring seedgermination, seedling growth and on hormonal analysisof test plants in petridishes . Water extract using differentconcentrations of sunflower leaves significantly inhibitedgermination rate and seedling growth and effect onhormones of plants in petridishes as compared to controland in pots its effect on Ec, pH, Mn, Ca, K, and on P.157

Identification of allelopathic compounds from Helianthus tuberosus L. leaves

https://iris.unito.it/bitstream/2318/67628/1/383-Identification%20of%20Allelopathic%20Compounds%20from%20Helianthus%20tuberosusL%20Leaves.pdf

Identification of allelopathic compounds from Helianthus tuberosus L. leaves

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