Relationship between photosynthetic activity and chlorophyll content in an isolated Quercus ilex tree during the year
1998
Gratani, L. | Pesoli, P. | Crescente, M.F. (Universita La Sapienza, Rome (Italy). Dipt. di Biologia Vegetale)
The relationship between chlorophyll (Chl) content and net photosynthetic rate (PN) in an isolated Quercus ilex tree, was explored. The highest PN was in March, May, and September (10.1 micromol m** (-2) s** (-1), maximum rate). PN decreased by 65 % when leaf temperature reached 34 deg C, and by 50 % when leaf temperature was 9 deg C. The highest Chl contents were in April, October [1.47 g kg** (-1)(d.m.), maximum value], and December. The lowest Chl content was found in July (0.78 g kg** (-1)). The decrease of PN in July was in close connection with the decrease of Chl content. On the contrary, the high Chl content during winter did not correspond with PN of this season. The high Chl (a+b) content during most of the year indicated that the photosynthetic apparatus remained basically intact also during stress periods.
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