Overcoming desiccation in an African cycad genus: Adaptive approaches for improving recruitment in Encephalartos

Ethics reference no. 214113833/2022

Cycad populations in the wild are declining due to human pressures, and recovery efforts are constrained by the high mortality of seeds and seedlings, particularly as a result of desiccation. Desiccation reduces seed survival and thus seedling recruitment in the wild. This limits the viability of cycad populations in the wild. Therefore, this study involved testing different substrates designed to retain moisture and thus improve cycad seed survival and juvenile establishment in the wild. It was hypothesized that the addition of water-retaining compounds, such as Coir and Hydrogel, into the growing medium would improve moisture availability and increase seed and juvenile establishment and survival under drought conditions. To test the hypothesis, experimental treatments comprising four substrates and three watering regimes, representing no drought, moderate drought and prolonged drought, were tested in a greenhouse to evaluate their effects on cycad establishment and survival. Data was collected substrates moisture content, seedling emergence, difference in plant mass, stomatal density, root volume, and plant growth, development and survival.