Abstract Detail



Ecophysiology

Perkowski, Evan [1], Waring, Elizabeth [2], Smith, Nicholas [3].

Carbon costs to acquire nitrogen are determined by interactions between nitrogen availability and light availability in two species with different acquisition strategies.

Plant nitrogen acquisition requires carbon allocated belowground to build roots and sustain microbial associations. This carbon cost to acquire nitrogen varies by nitrogen acquisition strategy; however, the degree in which these costs vary due to soil nitrogen availability or plant nitrogen demand has not been well tested under controlled conditions. We grew a legume (Glycine max ) and non-legume (Gossypium hirsutum) under four soil nitrogen levels to manipulate soil nitrogen availability and four light levels to manipulate plant nitrogen demand in a full-factorial greenhouse experiment. We quantified carbon costs to acquire nitrogen (gC gN-1) as the ratio of total root carbon (gC) to whole-plant nitrogen (gN) within each treatment combination. Light availability increased carbon costs in both species due to an increase in root carbon that was proportionally greater than the concurrent increase in whole-plant nitrogen. Soil nitrogen fertilization decreased G. hirsutum carbon costs due to a larger increase in whole-plant nitrogen than root carbon, but did not affect G. max carbon costs due to similar increases in root carbon and whole-plant nitrogen despite decreases in root nodulation. Carbon costs to acquire nitrogen were thus determined by plant nitrogen demand and an interaction between soil nitrogen availability and nitrogen acquisition strategy.


1 - Texas Tech University, Biological Sciences, 2901 Main Street, Lubbock, TX, 79409, US
2 - Northeastern State University, 611 N. Grand Ave., 611 N. Grand Ave., Texas Tech Unviersity, Tahlequah, OK, 74464, United States
3 - Texas Tech University, 2901 Main Street, Lubbock, TX, 79409, USA

Keywords:
carbon cost
nitrogen uptake
nitrogen acquisition
plant economics
aboveground-belowground interactions
light availability
nitrogen availability
nitrogen fixation.

Presentation Type: Oral Paper
Number: 0015
Abstract ID:50
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize,Physiological Section Best Paper Presentation


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