ISHS Acta Horticulturae 629: XXVI International Horticultural Congress: The Future for Medicinal and Aromatic Plants
INDIGENOUS PARAQUAT RESISTANCE IN KOREAN FOXGLOVE (REHMANNIA GLUTINOSA LIBOSCH.) AND IN VIVO MULTIPLE ADVENTITIOUS BUDS FORMATION |
| Authors: | C. Park, H. Park, N. Seong, J.E. Simon |
| Keywords: | Chinese foxglove, herbicide resistance, Korean foxglove, paraquat, dichloride, Rehmannia var. hueichingensis |
| Abstract:
Oriental or Korean foxglove (Rehmannia glutinosa Libosch., Fam. Scrophulariaceae) is used in a wide variety of medicinal drug applications in Korea, China and Japan. In traditional medicine, both the fresh and dry roots are used differentially in the treatment of wounds and bruises, as a poison antidote, and as a blood coagulant. Rice-wine cooked foxglove is used to improve the blood, as an overall tonic to improve health and vigor, in the treatment of diabetes and hypertension. Three types are used in traditional oriental medicine, Rehmannia glutinosa, native to Korea and another indigenous to Japan, and R. glutinosa var. hueichingensis, native to China. The foxgloves differ not only in their origin, but also in their anatomy and application. Korean foxglove is cultivated in the Republic of Korea and weed control is an expensive agricultural input by the small farmer. By chance, a Korean farmer observed that the foxglove plants under cultivation were not visually damaged following an application of paraquat, a potent non-selective herbicide. As a consequence, our research group was invited to confirm whether this population of Korean foxglove was ‘resistant’ to paraquat, and whether further selection is possible to develop a paraquat resistant Korean foxglove. Here, two populations, Korean foxglove, the purported resistant line, and a commercial Chinese foxglove variety, and observed paraquat sensitive variety, were greenhouse grown, and subjected to foliar application of paraquat over a wide concentration range (1x, 2x and 4x). The Korean foxglove population exhibited little damage, all plants appeared to survive the herbicide application two days after treatment, and continued to re-grow through the entire recovery period. Final survivability of the Korean foxglove was >83%, and final root growth and weight were greater in the paraquat treated plants than its untreated controls. In contrast, Chinese foxglove was sensitive at all paraquat concentrations, resulting in a complete die-back of all foliage two days after treatment yet 50-66.7% of plants survived the herbicide treatment. Those surviving plants exhibited reduced plant growth and root yield relative to their untreated controls. Following exposure to paraquat, we also observed in vivo multiple adventitious shoots formed (from 4.2% to 20.8%, from 1x to 4x rate) in the Korean foxglove, but no adventitious shoots were seen in the Chinese foxglove. Our results suggest that indigenous Korean foxglove is tolerant to paraquat, that clonal selection can be made for further selection to develop a paraquat resistant line. The mechanism of tolerance is unknown. | |
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