Root responses to domestication, precipitation and silicification: weeping meadow grass simplifies and alters toughness

Background and aims: Plant breeding usually focuses on conspicuous above-ground plant traits, yet roots fundamentally underpin plant fitness. Roots show phenotypic plasticity in response to soil conditions but it is unclear whether domesticated plants respond like their ancestors. We aimed to determine how root traits differed between ancestral and domesticated types of a meadow grass (Microlaena stipoides) under altered regimes of precipitation and soil silicon availability. Methods: We subjected the two grass types to three simulated precipitation regimes (ambient, +50%/deluge and − 50%/drought) in soil with (Si+) and without (Si−) silicon supplementation and then characterised root biomass, architectural complexity and toughness in addition to shoot traits. Results: Domestication increased root tissue density, decreased specific root length (SRL) and decreased root architectural complexity. Domestication also increased root strength under Si − conditions but not Si + conditions. Fine...