Functional Implications of Root Architectural and Anatomical Phenes for Soil Resource Capture

Open Access
Author:
Strock, Christopher
Graduate Program:
Plant Biology
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
February 13, 2019
Committee Members:
  • Jonathan Paul Lynch, Dissertation Advisor
  • Jonathan Paul Lynch, Committee Chair
  • Kathleen Marie Brown, Committee Member
  • Armen R. Kemanian, Committee Member
  • Jack Watson, Outside Member
Keywords:
  • Common bean
  • Phenotyping
  • Roots
  • Plant Physiology
  • Drought Stress
  • Phosphorus Stress
  • Root Architecture
  • Root Anatomy
  • Plant Nutrition
Abstract:
The common bean (Phaseolus vulgaris) is an important food security crop for smallholder famers throughout the developing world. Drought stress and poor soil fertility are some of the biggest constraints to yield of P. vulgaris in these regions. Breeding efforts to improve soil resource acquisition efficiency of the root system may be one of the most pragmatic strategies to sustainably mitigate yield deficits in marginal environments. Variation for architectural and anatomical root phenes has important effects on water and nutrient acquisition by modifying the distribution of root foraging in the soil, the metabolic costs of soil exploration, and the transport of water and nutrients. The following work utilizes in silico, greenhouse, and field trials to characterize architectural and anatomical root phenes in Phaseolus species and quantify their contribution to water and phosphorus capture. The results of this work suggest that 1) measures of root architecture in seedlings are representative of root architecture in the field, and these seedling root traits have important relationships with yield under a diversity of conditions. 2) Laser ablation tomography serves as a novel method to qualify and quantify root anatomical phenes and their interactions with edaphic organisms. 3) Under phosphorus deficit, genotypes with roots that favor primary growth over secondary growth have reduced metabolic costs, greater soil exploration, and greater phosphorus capture. 4) Variation for metaxylem vessel morphology impacts hydraulic conductance of the root system, and interacts with root system depth and water distribution in the field to affect water use under drought.