Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2007
Publication Date: 1/1/2008
Citation: Lucero, M.E., Barrow, J.R., Osuna, P., Reyes-Vera, I., Duke, S.E. 2008. Enhancing native grass productivity by cocultivating with endophyte-laden calli. Rangeland Ecology and Management. 61:124-130. Interpretive Summary: Callus cultures of four plant species native to the Chihuahuan desert (black grama grass, fourwing saltbush, alkali sacaton, and sand dropseed) were used as inoculum sources from which cryptic microorganisms were transferred to black grama grass and sand dropseed. Inoculated grasses were placed in randomly arranged field plots, where productivity was evaluated based on plant survival, plant size (height and crown diameter), above ground biomass production, and seed production. Stolon production was also recorded for black grama. Black grama plants responded to the inoculum with more rapid early growth and increased stolon production. Nearly half of the black grama plants inoculated with alkali sacaton endophytes behaved as annuals, exhibiting rapid early growth which terminated at the end of the growing season. These plants did not recover the following year. Black grama plants inoculated with fourwing saltbush endophytes produced more seed than untreated plants. Sand dropseed plants responded positively to all endophyte treatments. Increased survival rates and larger plants with more seeds were observed. Results indicate that uncultured endophytes can be utilized to significantly improve productivity of cultivated native grasses.
Technical Abstract: The influence native endophytes have on grass establishment and productivity was evaluated by co-cultivating Bouteloua eriopoda (Torr.) Torr. (black grama) or Sporobolus cryptandrus (Torr.) Gray (sand dropseed) seedlings with endophyte-laden calli from three of four native grass and shrub species; Atriplex canescens (Pursh) Nutt. (fourwing saltbush), S. cryptandrus, S. airoides (Torr.) Torr. (alkali sacaton), and B. eriopoda in-vitro. Following co-cultivation, grass seedlings were hardened and transferred to 3 replicate field plots each containing 16 grass plants of a single species which had been co-cultivated with a single callus species. Plant establishment rates, heights, crown diameters, above ground biomass, seed yields, and seed quality were compared. In B. eriopoda (black grama), significant increases in plant biomass were not observed. However, early plant heights and crown diameters, establishment rates, and stolon production were higher in some callus treatments. In S. cryptandrus (sand dropseed), all variables were positively influenced by one or more of the endophyte treatments. Biomass increases ranged from 2.5 to 3-fold over untreated plants, and harvested seed increased 5.9-fold in plants treated with endophytes from A. canescens (fourwing saltbush). Seed quality, determined by purity, germination rates, and tetrazolium assays, and did not differ across endophyte treatments for either grass. There is evidence that endophyte transfer is responsible for the altered vigor of treated plants, but this conclusion requires further study.