Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài: "Effects of phosphate deficiency on photosynthesis and accumulation of starch and soluble sugars in 1-year-old seedlings of maritime pine (Pinus pinaster Ait). | 801 Ann Sci For 1996 53 801-810 Elsevier INRA Original article Effects of phosphate deficiency on photosynthesis and accumulation of starch and soluble sugars in 1-year-old seedlings of maritime pine Pinus pinaster Ait M Ben Brahim1 D Loustau1 JP Gaudillère2 E Saur1 1 Laboratoire d ecophysiologie et de nutrition Inra domaine de Hermitage BP 45 33611 Gazinet cedex 2 Station de physiologie végétale centre de recherche de Bordeaux Inra BP 81 33883 Villenave-d Ornon France Received 27 April 1994 accepted 14 November 1995 Summary - Maritime pine seedlings were grown in 4 L pots filled with coarse sand in a greenhouse. Seedlings were supplied with a nutrient solution with three different concentrations of phosphorus 0 and mM . After 1 year of growth gas exchange measurements were performed on mature needles. From these measurements the main parameters of co2 assimilation the carboxylation efficiency the apparent quantum efficiency and the maximal rate of electron transport were estimated using the biochemical model of photosynthesis as described by Farquhar et al 1980 . Leaf nonstruc-tural carbohydrates were also analyzed. Phosphorus deficiency decreased the phosphorus foliar concentration but did not affect foliar nitrogen concentration. The maximal rate of photosynthesis the carboxylation efficiency and the apparent quantum efficiency decreased in phosphorus deficient seedlings. However the maximal rate of electron transport and stomatai conductance were not affected by phosphorus supply. Low phosphorus nutrition caused a dramatic increase in foliar starch level at the end of the photoperiod. These results indicate that inadequate phosphorus nutrition principally affected the dark reactions of photosynthesis the apparent quantum efficiency and starch accumulation. Pinus pinaster growth photosynthesis phosphorus deficiency glucidic status Resume - Effets d une carence en phosphate sur la photosynthèse et I accumulation d amidon et de sucres solubles Chez des .
