PRELIMINARY SURVEY OF ROOT AERENCHYMA IN TRIPSACUM

Tripsacum plants of the species dactyloides (eastern gamagrass) have b een observed to withstand flooded soil conditions and roots of this sp ecies have been observed to penetrate deep into heavy clay soils. One commonality between these conditions is the low oxygen environment sur rounding the roots due to water logging or soil compression. In both c ases, the presence of aerenchyma in T. dactyloides roots may have amel iorated the adverse impact of the low oxygen environment. Previously, we have found that some T. dactyloides accessions exhibit well-formed root aerenchyma even under well-aerated, non-stress environments which may allow a competitive advantage for this species in adapting to a w ide range of habitats. In this survey of root anatomy, 15 of 16 specie s of Tripsacum were evaluated to determine the extent to which aerench yma occur in a well-aerated, non-stress environment. Among the 15 spec ies, 26 accessions were surveyed. In only five of the 15 species were large, well-formed aerenchyma found. This indicates that the ability t o form aerenchyma under well-aerated, non-stress environments is not a universal adaptive mechanism within the genus and indicates the possi bility of developing additional supraspecific groups based on root cha racteristics.