Growth

Aconitum delphinifolium has biennial tubers that overwinter and break dormancy in the spring. These tubers send roots and shoots out by apical meristems. The tuberous roots consist of abnormal secondary growth where the secondary xylem appears to be “U” shaped, and parenchyma cells of secondary phloem make up the vast majority of the tuber (JianZhao, JiYaun, and Qing 2011). Rhizomes are produced from lateral buds on the tuber, which will form a daughter tuber at its extremity for the next year’s plant. Secondary xylem is produced in the stems, and a cork layer is found in at least one species of Aconitum (Dulin 2008). It is an herbaceous perennial with the parent plant only surviving one season, so it does not produce growth rings. It is unknown whether A. delphinifolium produces bulbils, but several other Aconitum species have been discovered with them. Bulbils are basically miniature bulbs, and they can be found growing in the leaf axils of some Aconitum species. They are commonly produced if the plant has failed to produce seeds, giving it three reproduction strategies (Farrell 2008). 

Works Cited

Dulin, Max. "An Investigation of Paedomorphic Secondary Xylem and Secondary Woodiness in Xanthoriza simplicissima, Coreopsis gigantea, and Mahonia bealei." Thesis Defense. Greensboro: University of North Carolina, 2008.

Farrell, Bonnie. "Histological Documentation and Ecological Implications of Bulbils in Aconitum noveborecense (Ranunculaceae), A Federally Protected, Threatened Plant Species." Thesis Defense. New Brunswick: Rutgers, October 2008.

JianZhao, Qi, Guo JiYaun, and Xu Qing. "Abnormal secondary growth and histochemical localization of alkaloids in root system of Aconitum flavum." Agricultural Science & Technology, 2011: 1313-1317.