Photosynthesis of a scots pine shoot: Test of a shoot photosynthesis model in a direct radiation field

• Published in: Agricultural and forest meteorology Vol. 39; no. 1; pp. 67 - 80
• Main Authors: Smolander, Heikki, Oker-Blom, Pauline, Ross, Juhan, Kellomäki, Seppo, Lahti, Tapani
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1987; Oxford Elsevier; New York, NY
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; Biometrics, statistics, experimental designs, modeling, agricultural computer applications; Crop climate. Energy and radiation balances; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities, techniques; Generalities. Biometrics, experimentation. Remote sensing; Generalities. Techniques. Climatology. Meteorology. Climatic models of plant production; Laboratory study; Experimental test; Europe; Quantization; Irradiance; Pinus sylvestris; Direction; Simulation; Morphology; Gymnospermae; Softwood forest tree; Finland; Coniferales; Spermatophyta; Mathematical model; Photosynthesis; Solar radiation; Phytoclimate
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/0168-1923(87)90017-7

The photosynthetic light curves of eight Scots pine ( Pinus sylvestris L.) shoots, each with a different structure, were measured in a direct radiation field at different positions relative to the radiation beam. Using a model of shoot geometry, the irradiance distributions on the needle surface area of the same shoots were simulated in each position. Using measurements of shoot photosynthesis, the photosynthetic light curve for a needle surface area element (a small area on the needle surface) was estimated indirectly for each shoot. Shoot photosynthesis was then calculated from the estimated photosynthetic light response curve of a needle surface area element and the irradiance distribution on the surface area of needles. Calculated rates for shoot photosynthesis agreed well with the measured rates. The mean irradiance on the needle surface area was the major component causing variation in the light response of a shoot irradiated from different directions, but the shape of the irradiance distribution on the needle surface area had a considerably smaller effect.