Effects of some plant canopies and wind conditions on fluctuating light waveform

The actual effects of light fluctuations within plant canopies have not yet been clarified. The purpose of this paper is to elucidate the effects of some phyllotaxises, planting density, leaf height and wind conditions on waveform of fluctuating light. In this study, indoor experiments were conducted using a model canopy. 1) Differences of the frequency bringing the spectral density of the fluctuating light within each canopy to a definite level or more, among 3 test phyllotaxises, were small for a weak wind (0.7ms-1. When the wind velocity was over 2.5ms-1, the frequency of each phyllotaxise was in the order of 2/5 alternate phyllotaxis decussate phyllotaxis distichous phyllotaxis. 2) Change of the peak value of power spectra at the planting densities from4 plant m(-2) to 244 plant m(-2), were small at the wind velocity 1.8 and 2.8ms-1, but large at 0.7ms-1). Relations were not observed between the peak value and planting densities. 3) The frequency range became large in proportion to the increase of height of leaf position at a standard wind speed (1.8ms-1) and under a strong wind (2.8ms-1). However, in weak wind (0.7ms-1) the range became small. 4) Though waveforms of fluctuating light were compared under some wind conditions, fluctuating or not, weak wind or strong, the differences among the waveforms were not obvious