Effect of specific leaf nitrogen on radiation use efficiency and growth of sunflower

摘要: Specific leaf nitrogen (SLN, g/m(2)) is known to affect radiation use efficiency (RUE, g/MJ) in different crops, However, this association and importance have not been well established over a range of regimes for held-grown sunflower (Helianthus annuus L.). An experiment was conducted investigate combinations rates applied on SLN, RUE, growth sunflower, A fully irrigated crop sown an alluvial-prairie soil (Fluventic Haplustoll) treated with five nitrogen, Greater increased biomass, grain number, yield, but did harvest index energy-corrected oil (0.4) or canopy extinction coefficient (0.88), Decreases biomass accumulation under low treatments were associated,vith reductions area (LAI) light interception, When SLN RUE examined together, both less the anthesis physiological maturity period, relatively stable between bud visible anthesis, effects confounded by high top maintaining reducing LAI, Measurements CO2 assimilation theoretical analyses supported that related The major effect early mediated distribution rather than direct alone. responses are more evident later growth, may be demand grain.