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Effects of phosphate supply and elevated CO 2 on root acid phosphatase activity in Pinus densiflora seedlings
Author(s) -
Norisada Mariko,
Motoshige Tetsuya,
Kojima Katsumi,
Tange Takeshi
Publication year - 2006
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200520558
Subject(s) - phosphate , chemistry , phosphorus , photosynthesis , pinus densiflora , nutrient , acid phosphatase , phosphorus deficiency , horticulture , zoology , botany , chlorophyll , biochemistry , biology , enzyme , organic chemistry
The exudation of root acid phosphatase (APase) is a plant response mechanism to phosphorus (P) deficiency. Under conditions of elevated CO 2 , P demand increases and possibly further enhances APase activity. We examined the activity of APase in 1‐year‐old ectomycorrhizal Pinus densiflora Sieb. et Zucc. seedlings grown in potted sand in the greenhouse under ambient (400 μmol mol – 1 ) and elevated (700 μmol mol –1 ) CO 2 with three modes of P supply: inorganic (NaH 2 PO 4 ; P in ), organic (inositol hexaphosphate dodecasodium salt; P org ), and no phosphate (P 0 ) for 78 d. Phosphorus limitations decreased P content in leaves and roots with lowest P content in P 0 treatments, irrespective of CO 2 conditions. However, P limitations decreased plant biomass at elevated CO 2 levels, but not at ambient CO 2 levels. The content in leaves of nutrients other than P was mostly unaffected by P supply, but decreased under elevated CO 2 . This observation was attributed to starch accumulation in leaves at elevated CO 2 , especially in the P 0 treatment. The photosynthetic activity (expressed per unit of chlorophyll) was unaffected by P supply, but tended to be less at elevated CO 2 . There was no increase in root APase activity of Pinus densifolia in response to the P shortage caused by elevated CO 2 .