Huge Impacts from Tiny Organisms: Novel Bacteria Improve Health and Quality of Floriculture Crops

Research poster
Nathan Nordstedt
Michelle Jones
Department of Horticulture and Crop Science

Drought stress is a major contributor to the loss of horticulture crop value due to its negative effects on plant growth and flowering. In addition, post-production drought stress can also reduce the physiological health of plants, negatively impacting crop quality at retail and with consumers. Application of microbe-containing biostimulant products can increase stress tolerance and crop quality, however the success of most biostimulants in greenhouse production systems is inconsistent. To provide the industry with new tools, our study developed a novel collection of bacteria originating from the rhizosphere of water-stressed greenhouse ornamental crops. Over 1,100 bacteria isolates were collected from plants in diverse greenhouse facilities and then screened in vitro. Selected isolates were preliminarily evaluated in planta and ten were selected for increasing plant size or flower number of water-stressed Petunia x hybrida plants. In addition to plant quality, bacteria application can increase stress tolerance by positively influencing the plant’s physiological health throughout severe drought stress and recovery. Therefore, a subsequent greenhouse trial evaluated each of the selected isolates for their ability to increase crop quality and physiological health of drought-stressed P. hybrida and Pelargonium x hortorum. Bacteria application improved plant quality by increasing plant size in both species and flower number of P. hybrida after recovery from drought stress. In addition, bacteria application improved plant health by increasing photosynthetic health and decreasing electrolyte leakage of plants during drought stress and recovery. Implementation of these bacteria can increase the overall profitability and sustainability of greenhouse production.