CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Functional Plant Biology   
Functional Plant Biology
Journal Banner
  Plant Function & Evolutionary Biology
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Evolutionary Reviews
Sample Issue
Call for Papers
For Authors
General Information
Submit Article
Author Instructions
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter LinkedIn

red arrow PrometheusWiki
blank image
Protocols in ecological and environmental plant physiology


Article << Previous     |     Next >>   Contents Vol 31(10)

Nitrogen source and water regime effects on barley photosynthesis and isotope signature

Marta S. Lopes A, Salvador Nogués A, José L. Araus A B

A Unitat de Fisiologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, E-08 028 Barcelona, Spain.
B Corresponding author; email: jaraus@ub.edu
PDF (195 KB) $25
 Export Citation


Water stress and nitrogen (N) availability are the main constraints on barley (Hordeum vulgare L.) yield in Mediterranean conditions. Here we studied the combined effects of N source and water regime (WR) on plant growth, photosynthesis and carbon isotope discrimination (Δ13C) in barley grown under controlled conditions. The effects of these conditions on plant N isotope discrimination against the fertiliser (Δ15N) was also examined to assess whether the natural variation in plant N isotope composition is a reliable indicator of N nutrition. Six experimental treatments were established with three nutrient solutions containing ammonium (NH4+), nitrate (NO3) or a mixture of the two (NH4+ : NO3), each either well watered or moderately water stressed. The NH4+ : NO3 treatment resulted in the greatest biomass accumulation and photosynthetic capacity in both WRs. The NH4+ plants showed accelerated phenology and depressed growth. They also had the lowest photosynthetic rates in both WRs. This effect was mainly due to stomatal closure, while electron transport and carboxylation capacity of leaves were less affected. Consistent with lower stomatal conductance, leaf Δ13C was lower in plants that received NH4+, indicating higher water use efficiency (WUE) not only when irrigated, but also under water stress. In addition, leaf Δ13C and photosynthetic N use efficiency (PNUE) correlated positively with each other and with shoot biomass in both WRs. However, NO3 treatment produced the greatest Δ15N, which was higher in leaves than in roots. Leaf Δ15N was decreased by water stress only in plants in the NO3 treatment. We conclude that leaf Δ13C is an adequate trait to assess the differences in growth, photosynthetic activity and WUE caused by distinct N sources. However, the usefulness of natural abundance of 15N in plant tissue as a nitrogen source marker is restricted by the effect of WR and internal plant fractionation, at least for plants that received NO3.

Keywords: ammonium, Hordeum vulgare, nitrate, water stress, water use efficiency.

Subscriber Login

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2015