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Photosynthesis and respiration of Pinus pumila needles in relation to needle age and season
Author(s) -
Kajimoto Takuya
Publication year - 1990
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02347008
Subject(s) - photosynthesis , respiration , botany , pinus <genus> , growing season , horticulture , respiration rate , zoology , biology
Abstract Rates of net photosynthesis and dark respiration were measured for detached needles of Pinus pumila trees growing on the Kiso mountain range in central Japan in 1987. Dependency of photosynthesis on light and temperature was examined in relation to needle age and season. The light saturation point of net photosynthesis was lower in 3‐ and 4‐yr‐old needles than that in current (flushed in 1987), 1‐ and 2‐yr‐old needles. P nmax , net photosynthetic rates at 1000 μmol m −2 s −1 and 15°C, of needles from 1‐ to 4‐yr‐old generally decreased with needle age. P nmax of 1‐ to 4‐yr‐old needles became higher in August than in other months, and P nmax of current needles did so in September. Current needles showed high respiration rates (at 15°C) only in August. Optimum air temperatures for net photosynthesis at 1000 μmol m −2 s −1 were between 10 and 15°C for current and 1‐yr‐old needles. The temperature coefficient of dark respiration rates was 2.3–3.3 for current needles from August to October, and 2.2 for 1‐yr‐old needles in mid‐July.