View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UNL | Libraries University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Agricultural Publications from USDA-ARS / UNL Faculty Research Service, Lincoln, Nebraska 2011 Phytotoxicity of Antofine from Invasive Swallow-Worts Donna M. Gibson USDA-ARS, [email protected] Stuart B. Krasnoff USDA-ARS Jeromy Biazzo USDA-ARS Lindsey Milbrath USDA-ARS Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub Gibson, Donna M.; Krasnoff, Stuart B.; Biazzo, Jeromy; and Milbrath, Lindsey, "Phytotoxicity of Antofine from Invasive Swallow-Worts" (2011). Publications from USDA-ARS / UNL Faculty. 1250. https://digitalcommons.unl.edu/usdaarsfacpub/1250 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. J Chem Ecol (2011) 37:871–879 DOI 10.1007/s10886-011-9994-4 Phytotoxicity of Antofine from Invasive Swallow-Worts Donna M. Gibson & Stuart B. Krasnoff & Jeromy Biazzo & Lindsey Milbrath Received: 4 February 2011 /Revised: 26 June 2011 /Accepted: 28 June 2011 /Published online: 8 July 2011 # Springer Science+Business Media, LLC (outside the USA) 2011 Abstract Pale swallow-wort (Vincetoxicum rossicum) and Introduction black swallow-wort (V. nigrum) are two emerging invasive plant species in the northeastern United States and Two emerging invasive plant species in the northeastern southeastern Canada that have shown rapid population United States and southeastern Canada are pale swallow- expansion over the past 20 years. Using bioassay-guided wort [Vincetoxicum rossicum (Kleopow) Barbarich = fractionation, the known phytochemical phenanthroindoli- Cynanchum rossicum (Kleopow) Borhidi] and black zidine alkaloid, (−)-antofine, was identified as a potent swallow−wort [V.nigrum(L.) Moench = C. louiseae phytotoxin in roots, leaves, and seeds of both swallow-wort Kartesz & Gandhi]. Both exist as herbaceous, perennial, species. In seedling bioassays, (−)-antofine, at μM concen- twining vines and are related to milkweeds (Apocynaceae, trations, resulted in greatly reduced root growth of subfamily Asclepiadoideae). Pale swallow-wort is native Asclepias tuberosa, A. syriaca, and Apocynum cannabinum, to the Ukraine and European Russia and possesses pink to three related, native plant species typically found in habitats maroon flowers, whereas black swallow-wort is native to where large stands of swallow-wort are present. In contrast, southwestern Europe and bears dark purple to black antofine exhibited moderate activity against lettuce, and it flowers (Markgraf, 1972). These species were introduced had little effect on germination and root growth of either into North America, probably as ornamentals, in the mid- to black or pale swallow-wort. In disk diffusion assays, late-1800s, but not until the 1970’s were concerns raised about antifungal activity was observed at 10 μg and 100 μg, the invasive potential of swallow-worts (Pringle, 1973). The while antibacterial activity was seen only at the higher last 20 years have seen a rapid expansion of both species level. Although both swallow-wort species display multiple (Lawler, 2000; DiTommaso et al., 2005b), which are growth and reproductive characteristics that may play an currently reported in 21 U.S. states from New England to important role in their invasiveness, the presence of the Maryland and west to Nebraska and Kansas, with an highly bioactive phytochemical (−)-antofine in root and additional report from California, and the Canadian provinces seed tissues indicates a potential allelopathic role in of Ontario and Quebec (Kartesz, 1999; DiTommaso et al., swallow-worts’ invasiveness. 2005b;USDA2009). The primary infestations are in New England, New York, and Ontario, and both species are listed Key Words Antofine . Phytotoxin . Swallow-worts . as noxious weeds or prohibited invasive species in Vermont, Vincetoxicum . Cynanchum . Allelopathy. Invasiveness . New Hampshire, Massachusetts, and Connecticut (USDA Allelopathic potential 2009). Both pale and black swallow-wort have multiple growth D. M. Gibson (*) : S. B. Krasnoff : J. Biazzo : L. Milbrath and reproductive characteristics that may play a role in their USDA, Agricultural Research Service, invasiveness. Swallow-wort vines can grow 1–2 m or more Biological Integrated Pest Management Research Unit, during the growing season, producing dense, tangled Robert W. Holley Center for Agriculture and Health, masses of vines that climb up and over supporting Tower Road, Ithaca, NY 14853, USA vegetation (Christensen, 1998;Douglassetal.,2009). e-mail: [email protected] Stand densities can average 134 stems per m2 and 1800 872 J Chem Ecol (2011) 37:871–879 seedlings per m2 (Smith et al., 2006). Large stands (Cappuccino, 2004); antofine was identified as the antimi- reportedly exclude most other vegetation, including the crobial agent, while the component(s) responsible for related milkweeds, and are encroaching on at least five phytotoxic or antifeedant activity has not been identified threatened or endangered species in New York and New (Mogg et al., 2008). Similar phytotoxic effects of both root England and on the globally-rare alvar communities in exudates and tissue leachates from pale and black swallow- Ontario and New York (Haribal and Renwick, 1998; wort on lettuce and butterfly milkweed root growth recently Lawler, 2000; Tewksbury et al., 2002; Douglass et al., have been reported (Douglass et al., 2011). 2009). Perennating buds produced on the rootstock give We undertook this study to determine if specific phyto- rise to one or more herbaceous stems in the spring, and chemical constituents from the swallow-worts possess phyto- additional buds will sprout if stems are damaged (DiTommaso toxic activity, a necessary step to evaluate whether allelopathy et al., 2005b). Flowering is indeterminate, extending from could play a role in swallow-worts’ ability to displace native mid-May into August, and seeds bear an apical tuft of hairs, plant species in the environment. We herein report that the which aids in long-distance dispersal (Ladd and Cappuccino, known phytochemical antofine is present in root, shoot, and 2005). Both swallow-wort species are self-compatible and leaf, and seed extracts of both pale and black swallow-wort, can self-pollinate or are cross-pollinated by insects (Lumer and that it has significant phytotoxicity against some related and Yost, 1995; St. Denis and Cappuccino, 2004). Seed native plant species with little effect against pale or black production can be prolific in high-light environments— swallow-wort germination and root development. around 32,000 seeds per m2 for high density stands of pale swallow-wort, and seeds are polyembryonic, containing 1– 8 embryos (Cappuccino, 2004; DiTommaso et al., 2005a; Methods and Materials Smith et al., 2006). Polyembryony may contribute to enhanced seedling establishment and survival rates, which Plant Material Five plants of pale swallow-wort were can be over 50% for pale swallow-wort (DiTommaso et al., excavated from Robert G. Wehle State Park, Jefferson 2005a; Ladd and Cappuccino, 2005; Hotchkiss et al., 2008). Co., New York, in May 2005, and placed into a cooler for Both species are drought tolerant and can grow in soils of a transport to the laboratory where the roots (with stems wide range of pH (DiTommaso et al., 2005b; Magidow et al., attached) were rinsed in several volumes of water to 2008). Pale swallow-wort also is shade tolerant, although in remove remaining soil. After removal of the stem and heavily shaded areas, little reproduction by seed occurs crown area, roots were weighed, frozen at −20°C, and then (Smith et al., 2006; Hotchkiss et al., 2008). lyophilized to dryness and stored at −20°C until extracted. What is not clear is whether allelopathy also plays a role Rootstocks of black swallow-wort were excavated from in the invasiveness of swallow-wort. Members of the Bear Mountain State Park, Rockland Co., New York, in Apocynaceae (including the Asclepiadoideae) are regarded September 2005. They were held under refrigeration until as poisonous to humans and other mammals (Wiegrebe et al., January 2006 and then grown in a greenhouse for 4 mo 1970; Haznagy and Toth, 1973;Haeggstrom,1990). In North until being harvested and prepared as noted above. For seed America, swallow-wort plants sustain minimal damage from extractions, pale swallow-wort seed was collected in herbivory, as deer rarely browse them and few arthropod August 2008 from fields in Great Gully Preserve, (Cayuga herbivores feed on them (Christensen, 1998; DiTommaso et Co.), New York,and black swallow-wort seed was collected al., 2005b; Ernst and Cappuccino, 2005; Milbrath, 2010). in August 2008 from fields in Bear Mountain State Park, Phenanthroindolizidine alkaloids, primarily (−)-antofine (Rockland Co.), New York. After pods were dried and and antofine oxide, as well as several less abundant crushed to release seeds, the majority of pod and pappus derivatives, have been isolated from the roots and aerial materials were removed by hand vacuum, and then seeds parts of V. hirundinaria Medik. (Wiegrebe et al., 1969; were sieved using