Submitted to: Proceedings of the 3rd. Eastern Native Grass Symposium
Publication Type: Proceedings
Publication Acceptance Date: 7/3/2003
Publication Date: 10/21/2004
Citation: Skinner, R.H., Zobel, R.W., Skaradek, W. 2004. Aerenchyma development in native warm-season grass cultivars. Proceedings of the 3rd. Eastern Native Grass Symposium. p. 48-52. Interpretive Summary: Plants growing in riparian buffers are subjected to a variety of stresses due to periodic flooding of their habitat. Many aquatic plant species develop large intercellular air-spaces known as aerenchyma that allow movement of oxygen down into submerged root tissues, encouraging continued root growth and nutrient uptake. In a pot study, we surveyed 26 native warm-season grass cultivars from 6 species to evaluate their ability to extend roots into flooded soils and to determine if the presence of aerenchyma improved root growth. All the cultivars we examined formed aerenchyma to some extent, even when soils were not flooded. Root growth was slower than average for cultivars with limited aerenchyma development, while extensive aerenchyma development was usually associated with increased root growth into flooded soils. However, not all cultivars with extensive aerenchyma formation performed well under flooding. These relatively poor performing cultivars also had poor root growth when soils were not flooded and appeared to have slow growth in general compared to the other cultivars in the study. The superior performing cultivars identified in this study will be further tested under field conditions and the information obtained will serve to improve NRCS field office recommendations to landowners in choosing the best-suited materials for flooded sites.
Technical Abstract: The primary objective of this study was to determine the suitability of selected warm-season grass species/cultivars for use in riparian buffers where flooding can be expected. This study focused on the development of aerenchyma in the roots of plants placed under flooding compared with non-flooding conditions. One-year old plants from twenty six cultivars representing six native warm-season species (big bluestem, Andropogon gerardii, Vitman., 7 cultivars; little bluestem, Schizachyrium scoparium Michx., 1 cultivar; switchgrass, Panicum virgatum L., 10 cultivars; indiangrass, Sorghastrum nutans L., 5 cultivars; prairie cordgrass, Spartina pectinata L.,1 cultivar; and eastern gamagrass, Tripsacum dactyloides L., 2 cultivars) were transplanted into 15-cm diameter by 120-cm deep PVC pots and grown under well-drained or waterlogged conditions. After approximately 100 d, pots were opened and root samples collected for root length distribution and aerenchyma formation determinations. Aspects of aerenchyma development included percent of root cross sectional area as aerenchyma and whether the aerenchyma development was schizogenic (typical of constitutive aerenchyma) or lysigenic (characteristic of facultative aerenchyma which usually develops after stress initiation). Cultivars with limited aerenchyma development always had poor root growth into saturated soils. Conversely, cultivars with extensive aerenchyma development usually, but not always, had better than average root growth under anaerobic conditions. Suitable plant materials for inclusion in riparian buffers were found among many warm-season species although some species, such as eastern gramagrass, appeared to be more likely than others, such as big bluestem, to provide cultivars that were tolerant of anaerobic soils.