Perennial grass root system specializes for multiple resource acquisitions with differential elongation and branching patterns

• Published in: Frontiers in plant science Vol. 14; p. 1146681
• Main Authors: Glass, Nicholas T, Yun, Kyungdahm, Dias de Oliveira, Eduardo A, Zare, Alina, Matamala, Roser, Kim, Soo-Hyung, Gonzalez-Meler, Miquel
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 17-03-2023; Frontiers Media S.A
• Subjects: BASIC BIOLOGICAL SCIENCES; functional traits; grass; lateral root; plant resources; Plant Science; root growth; root modeling; split root; water acquisition; plant resources; functional traits; grass; split-root; water acquisition; root growth; lateral root; root modeling
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2023.1146681

Roots optimize the acquisition of limited soil resources, but relationships between root forms and functions have often been assumed rather than demonstrated. Furthermore, how root systems co-specialize for multiple resource acquisitions is unclear. Theory suggests that trade-offs exist for the acquisition of different resource types, such as water and certain nutrients. Measurements used to describe the acquisition of different resources should then account for differential root responses within a single system. To demonstrate this, we grew
in split-root systems that vertically partitioned high water availability from nutrient availability so that root systems must absorb the resources separately to fully meet plant demands. We evaluated root elongation, surface area, and branching, and we characterized traits using an order-based classification scheme. Plants allocated approximately 3/4th of primary root length towards water acquisition, whereas lateral branches were progressively allocated towards nutrients. However, root elongation rates, specific root length, and mass fraction were similar. Our results support the existence of differential root functioning within perennial grasses. Similar responses have been recorded in many plant functional types suggesting a fundamental relationship. Root responses to resource availability can be incorporated into root growth models
maximum root length and branching interval parameters.