HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bange, M. P. Articles by Rickert, K. G. Search for Related Content PubMed Articles by Bange, M. P. Articles by Rickert, K. G. Agricola Articles by Bange, M. P. Articles by Rickert, K. G.

Effect of Specific Leaf Nitrogen on Radiation Use Efficiency and Growth of Sunflower

CSIRO Plant Industry, Cotton Res. Unit, Locked Bag 59, Narrabri, NSW 2390, Australia
Agric. Production Systems Res. Unit, P.O. Box 102, Toowoomba, QLD, 4350, Australia
Plant Production Dep., The Univ. of Queensland Gatton College, Lawes, QLD, 4343, Australia

^* Corresponding author (mikeb{at}mv.pi.csiro.au).

Specific leaf nitrogen (SLN, g/m²) is knownto affect radiation use efficiency (RUE, g/MJ) in different crops. However, this association and importance have not been well established over a range of different nitrogen regimes for field-grown sunflower (Helianthus annuus L.). An experiment was conducted to investigate different combinations and rates of applied nitrogen on SLN, RUE, and growth of sunflower. A fully irrigated crop was sown on an alluvial-prairie soil (Fluventic Haplustoll) and treated with five combinations of applied nitrogen. Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy-corrected for oil (0.4) or canopy extinction coefficient (0.88). Decreases in biomass accumulation under low nitrogen treatments were associated with reductions in leaf area index (LAI) and light interception. When SLN and RUE were examinedto gether, both were less in the anthesis to physiological maturity period, but relatively stable between bud visible and anthesis. However, the effects of canopy SLN on RUE were confounded by high SLN in the top of the canopy and the crop maintaining SLN by reducing LAI. Measurementosf leaf CO₂ assimilation and theoretical analyses of RUE supported that RUE was related to SLN. The major effect of nitrogen on early growth of sunflower was mediated by leaf area and the distribution of SLN in the canopy rather than direct effects of canopy SLN on RUE alone. Greater responses of RUE to SLN are more evident later in growth, and may be related to the demand of nitrogen by the grain.

Received for publication March 12, 1996.

This article has been cited by other articles:

				S. P. Milroy and M. P. Bange Nitrogen and Light Responses of Cotton Photosynthesis and Implications for Crop Growth Crop Sci., May 1, 2003; 43(3): 904 - 913. [Abstract] [Full Text] [PDF]