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Iván Ordóñez Vásquez

Doctor of Philosophy, (Plant Science)
Study Completed: 2020
College of Sciences

Citation

Thesis Title
Pursuing pasture tolerance and resilience through species with different functional traits and soil-plant-water interactions

In pastures, the combination of species with different functional traits confer niche differentiation. As a result, interspecific competition for resources is less intense. This study evaluated the shallow-rooted (Lolium perenne and Trifolium repens) and deep-rooted species (Bromus valdivianus and Plantago lanceolata) to determine, 1) The defoliation criterion for B. valdivianus growth, and 2) The morphophysiological mechanisms (i.e. gas exchange, stomatal aperture, tiller population) and growth dynamics of pastures containing these species. Bromus valdivianus was classified as a ‘six-leaf’ species, with a greater leaf area but lower tiller population per plant compared to L. perenne; along with P. lanceolata, show higher soil water restriction tolerance due to structural and physiological mechanisms that increment the soil water extraction, reflected in the photosynthesis, leaf osmotic and leaf water potentials. Mr Ordóñez Vásquez’s study found that pasture species that differ in species functional traits contribute to a higher biomass production during stress periods.

Supervisors
Associate Professor Ignacio Lopez Campbell
Professor Peter Kemp
Professor Danny Donaghy
Associate Professor David Horne