The unique root form and function on the Tibetan Plateau.

Abstract

Root traits, particularly anatomical traits, underpin root functions necessary for plant survival and adaptation. However, the coordination of root traits in extreme environments remains unresolved. We linked root functions that encompass foraging, uptake, and mining to anatomical traits of absorptive roots of typical and common species on the Tibetan Plateau and compared them with those in other regions globally. Our results showed that in alpine grasslands of the Tibetan Plateau, root functions were governed by root diameter and associated anatomical traits, rather than by specific root length (SRL, an indicator of root foraging) as observed globally. Specific root respiration (an indicator of active nutrient uptake) scaled with tube size and number within the root vascular system, whereas root exudation rate and acid phosphatase activity (indicators of nutrient mining) were linked to cortex cell size and layer number. These anatomical adaptations contrast with global patterns, where higher SRL supports nutrient acquisition through reduced construction costs. Our findings reveal unique root forms and functions in the alpine environments, highlighting the importance of cellular anatomy in shaping plant function in extreme environments.