Contrasting rhizosheath formation capacities in two maize inbred lines: implications for water and nutrient uptake

Background and aims

Rhizosheath, the soil attached to plant roots, may enhance drought resilience by improving water and nutrient uptake. This study evaluates the effects of rhizosheath formation on water and nutrient absorption from soils with different textures and moistures.

Methods

Two maize inbred lines R109B (Rh +) and Ky228 (Rh-), known for their distinct rhizosheath formation yet having identical root morphology, were cultivated in loamy sand and loamy soils. When plants were 45 days old, a controlled soil drying cycle was initiated and parameters such as plant transpiration rate (E), leaf water potential (\({\psi }_{leaf}\)), and soil water content/potential were monitored. At the end of soil drying cycle, the total nutrient uptake in the plants’ shoots was assessed.

Results

Rh + demonstrated a denser rhizosheath, particularly in loamy sand, correlating with increased root hair development. Rh + plants in loamy sand had a 1.73-fold increase in normalized mass rhizosheath compared to loam soil. In moderate moisture, Rh + exhibited improved soil–plant-water relationships, evidenced by higher midday E and \({\psi }_{leaf}\) in loamy soil than Rh-. However, no significant differences were noted under severe drought between Rh + and Rh-, likely attributed to diminished root hairs functionality. In loamy sand, Rh + plants exhibited 1.5 times higher phosphorus uptake, 1.46 times higher calcium uptake, and 2.02 times higher manganese uptake compared to Rh-.

Conclusion

Root hair development is a crucial factor in rhizosheath formation. The efficacy of the rhizosheath in enhancing water and nutrient uptake is significantly influenced by soil texture and moisture conditions.