THE EDAPHIC CONTROL OF PLANT RESPONSE TO CLIMATE CHANGE: EXTENT, INTERACTIONS AND MECHANISMS OF PLANT ADAPTATION

Open Access
Author:
Jaramillo-Velastegui, Raul Ernesto
Graduate Program:
Horticulture
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
October 14, 2008
Committee Members:
  • Jonathan Paul Lynch, Dissertation Advisor
  • Jonathan Paul Lynch, Committee Chair
  • Kathleen Marie Brown, Committee Member
  • Douglas Alan Miller, Committee Member
  • Douglas Brian Beegle, Committee Member
Keywords:
  • Olsen P
  • available phosphorus
  • nutrient dilution
  • nutrient accumulation
  • soil orders
  • Festuca arundinacea
  • elevated CO2
  • root formation
  • drought
  • aerenchyma
  • Metabolic costs
  • Bray P
  • climate change
  • land cover land use
  • LULC
  • critical value
Abstract:
We carried out research that confirmed significant interactions between the properties of 10 soil orders and atmospheric CO2 level (400 vs. 800 ppm) in the physiology and growth of the C3, temperate grass Festuca arundinacea. The results suggest that only a few, fertile soils are able to increase plant productivity with elevated CO2. Most other soil orders presented mineral deficiencies and imbalances that restricted plant growth. These reductions occurred together with dilution or accumulation of minerals and carbohydrates in the leaf under elevated CO2. In order to understand how much vegetated land in Earth may suffer from edaphic limitations and be affected concurrently by climate change, we developed a new map of available phosphorus at a global scale. The map was the result of assigning soil units with characteristic available phosphorus values calculated with data obtained from global and regional soil surveys. To create the map, we employed more than 5400 records on Olsen and Bray available phosphorus. Our map confirms the pervasive nature of P limitation, and indicates that about 50% of low P agricultural land may experience significant increases in temperature at the end of the century, with most of these areas located in the tropics. Finally, looking at the mechanisms that plants exhibit to adapt to soil-related (edaphic) stresses, we studied the effects of root metabolic costs on soil exploration in maize. Plants that reduced their living root tissue volume either by producing thinner roots or by the formation of aerenchyma, were able to increase their root system which was associated with increased tolerance to water stress. Interestingly, our results indicate a root type-specific increase in the length of seminal roots associated with less metabolic burden and reduced water stress.