Utilizing a multipoint measuring system of photosynthetically active radiation in photosynthetic studies within canopies

Journal Article (Journal Article)

A novel multipoint measuring system of photosynthetically active radiation (PAR) has been constructed and operated within a Scots pine canopy. A regular grid of 800 measuring points has been incorporated into a cuvette to observe the spatial and temporal distribution of PAR incident on the needles of a twig along with simultaneous measurements of the CO2 exchange in order to determine the dependence of photosynthesis on PAR. It was shown that large errors can result if the photosynthetic rate is estimated using the mean value of PAR instead of the instantaneous values of PAR detected at given points in the region of the needles. The results demonstrate that the obtained regression between the CO2 exchange rate estimated using the multipoint PAR measuring system and the measured CO2 exchange rate is as good within a canopy as in unshaded conditions.

Full Text

Duke Authors

Cited Authors

  • Palva, L; Garam, E; Palmroth, S; Sepponen, R; Hari, P

Published Date

  • January 1, 1998

Published In

Volume / Issue

  • 32 / 4

Start / End Page

  • 311 - 319

International Standard Serial Number (ISSN)

  • 0037-5330

Digital Object Identifier (DOI)

  • 10.14214/sf.673

Citation Source

  • Scopus