THE INFLUENCE OF ROOTING DEPTH ON NITROGEN UPTAKE IN ZEA MAYS L. UNDER OPTIMUM AND N-DEFICIENT CONDITIONS
Open Access
Author:
Sutherland, Chelsea Anne
Area of Honors:
Horticulture
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Jonathan Paul Lynch, Thesis Supervisor Kathleen Marie Kelley, Thesis Honors Advisor Jonathan Paul Lynch, Thesis Supervisor
Keywords:
root architecture nitrogen fertilizer
Abstract:
A well developed root system is a necessity for the acquisition of nutrients. Nitrogen (N) is predominantly found in water soluble chemical compounds that are highly mobile and expected to leach to deeper soil layers in the course of the cropping season. The purpose of this study was to evaluate the importance of root architectural traits of maize genotypes (Zea mays L.) under optimum and N-deficient conditions. It was hypothesized that deep rooted plants would be better able to acquire N and thus have enhanced performance. Maize inbred lines with contrasting root architecture: three genotypes with a shallow rooting system and 4 with a deep rooting system were sown in a randomized complete split-plot design. Root systems were measured destructively at six weeks after planting, at flowering, and at physiological maturity. Nitrogen acquisition by the plant was monitored over time by measuring leaf nitrogen content and SPAD as a proxy-measure for leaf chlorophyll. Furthermore grain yield was measured. The results indicated that steeper root angles produce deeper roots, and root angles, depth and branching are negatively correlated. Performance of both shallow and steep genotypes was similar under both conditions, as shallow genotypes responded to N deficient conditions by producing steeper root angles over time. These structural alterations facilitated N acquisition and minimized the differences between rooting types.
