Drought Eliminates the Difference in Root Trait Plasticity and Mycorrhizal Responsiveness of Two Semiarid Grassland Species with Contrasting Root System

Abstract

Root traits and arbuscular mycorrhizal (AM) fungi are important in determining the access of plants to soil resources. However, whether plants with different root systems (i.e., taproot vs. fibrous-root) exhibit different root trait plasticity and mycorrhizal responsiveness under drought remains largely unexplored. Tap-rooted Lespedeza davurica and fibrous-rooted Stipa bungeana were grown in monocultures in sterilized and live soils, followed by a drought treatment. Biomass, root traits, root colonization by AM fungi, and nutrient availability were evaluated. Drought decreased biomass and root diameter but increased the root:shoot ratio (RSR), specific root length (SRL), soil NO3−-N, and available P for the two species. Under control and drought conditions, soil sterilization significantly increased the RSR, SRL, and soil NO3−-N for L. davurica, but this only occurs under drought condition for S. bungeana. Soil sterilization significantly reduced AM fungal root colonization of both species, but drought significantly increased it in live soil. In water-abundant conditions, tap-rooted L. davurica may depend more on AM fungi than fibrous-rooted S. bungeana; however, under drought conditions, AM fungi are of equal importance in favoring both plant species to forage soil resources. These findings provide new insights for understanding the resource utilization strategies under climate change.

First Report of Fungal Pathogens Causing Leaf Spot on Sorghum–Sudangrass Hybrids and Their Interactions with Plants

“…The symptoms of SCBZSL1 and SCBZSX5 were similar. The growth indexes [9] (number of rhizomes, root bulk density, plant height, and root length) of SCBZSL1-susceptible plants were lower than control groups but significantly better than those inoculated with SCBZSX5. SCBZSW6-susceptible plants exhibited typical symptoms but had the least effect on the growth of sorghum-sudangrass hybrids.…”

Does arbuscular mycorrhizal fungi inoculation influence soil carbon sequestration?

“…Symbiotic relationships between plants and AMF depend on the benefits that host plants receive from the symbionts, which are largely affected by plant traits and AMF species. Plant root morphology (root architecture) and photosynthetic pathway (C3 or C4) reflect the nutrient uptake ability and energy supply condition of plants therefore influencing the reliance of plants on mycorrhizal symbiosis (Chandrasekaran et al 2016(Chandrasekaran et al , 2019Li et al 2023;Duan et al 2023). Evidence shows that plants with tap-rooted system are more dependent on AMF and benefit more from mycorrhiza than the fibrous-rooted plants (Yang et al 2015).…”