EEB Seminar- Sept. 21

This week the department welcomes Harris Ivens from Queen’s University:

As above so below? – Impacts of water limitation on growth and nutrient accumulation by a crop plant and its soil microbes across a fertility gradientHarris Ivens

Strategies to increase yields, fertilizer use efficiency, and drought stress tolerance in agricultural crops are urgently needed to meet future global food demands, especially in the context of a changing climate. Plants respond to water limitation by accumulating solutes, yet solute accumulation has not been well studied across fertilizer gradients. Conventional agricultural practice assumes that increasing fertilizer additions results in larger but chemically identical plants. However, a growing body of literature has demonstrated that increased nutrient availability results in ratio changes of organic (i.e. glucose, proline) to inorganic (i.e. NO3, PO4) solutes in sap pressed from leaves. Our study asks: Does the ratio of organic to inorganic solutes in leaf sap affect tolerance to reduced water availability? We used a greenhouse experiment to investigate the effects of three levels of nitrogen and potassium fertilizer (NK) additions on shoot growth, leaf sap composition, and soil microbial nutrient pools of replicate Collard greens (Brassica oleracea, n=9) before and after a water limitation treatment. Our results demonstrate that organic and inorganic solute concentrations in leaves and soil microbes were affected by the fertilizer addition and water limitation treatments, but these differences in solute concentrations did not affect the pattern of plant growth during the water limitation period. However, we found significant relationships among leaf sap, soil microbial biomass, and bulk soil nutrient pools that will contribute to the development of new crop assessment tools to increase precision in nitrogen fertilizer use and reduce harmful run-off, leaching, and gaseous nitrogen losses from agricultural lands.

This seminar will be held in the EEB Lounge of the BioSciences Complex, Room 4338, from 12:30-1:30pm.

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