Abstract Detail

Ecophysiology

Khasanova, Albina [1], James, Jeremy [2], Drenovsky, Rebecca [3].

Impacts of drought on mineral nutrition of grasses and forbs in the Intermountain West.

Drought decreases plant growth and limits their ability to access soil nutrients. However, it is unclear how drought impacts plant nutrient budgets, resource use efficiency and internal nutrient recycling (resorption), important components of whole plant performance. We hypothesized that drought may result in higher green leaf N (due to its negative effects on growth) but decreased photosynthetic nitrogen use efficiency and resorption. For this experiment the perennial grasses, Elymus elymoides, Festuca idahoensis, and Pseudoegneria spicata; the native forbs, Achillea millefolium and Sphaeralcea munroana; and the non-native forbs Centaurea stoebe and Linaria dalmatica, were grown under high and low water availability. Droughted plants had higher green leaf nitrogen concentrations(P<0.0001) but lower photosynthetic nitrogen use efficiency (P<0.0001).In response to drought, senesced leaf nitrogen concentration (a measure of resorption) was species specific (P<0.0001). In Achillea millefolium, Centaurea stoebe, Linaria dalmatica, Festuca idahoensis, Pseudoegneria spicata senesced leaf nitrogen increased with lower water availability. However, Sphaeralcea munroana showed no differences between control and drought plants while Elymus elymoides had lower senesced leaf nitrogen under drought.There was a significant species by water interaction for senesced leaf C:N ratio (P=0.002), with most species having a higher C:N ratio under drought (P=0.0001) while two species (Linaria dalmatica, Pseudoegneria spicata)did not show such effect. Higher senesced leaf C:N could have potential negative impacts on soil nutrient cycling. Future experiments should focus on the impact of drought on mineral nutrition in more closely related species (i.e., congener pairs) to account for potential phylogenetic effects on plant nutrient resorption.

Broader Impacts:

1 - John Carroll University, Biology Department, 20700 North Park Blvd, University Heights, OH, 44118, USA
2 - USDA-ARS, 67826A Hwy 205, Burns, OR, 97720, USA
3 - John Carroll University, Biology, 20700 North Park Blvd, University Heights, OH, 44118, USA

Keywords:
resorption
plant nutrient budgets
nitrogen
invasive species
leaf litter.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM
Number: PEP001
Abstract ID:168