Folia Horticulturae

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Effect of light intensity on growth and chlorophyll fluorescence of Rhododendron microcuttings during acclimatisation

Bożena Matysiak

Research Institute of Pomology and Floriculture
Pomologiczna 18, 96-100 Skierniewice, Poland
e-mail: bmatys@insad.pl

Survival, growth, and chlorophyll a fluorescence of in vitro propagated rhododendron ‘Alfred’ at two light intensities 75 and 150 μmol m-2 s-1 PPFD during acclimatisation were evaluated. High survival and better growth were obtained at higher light intensity. Maximum quantum efficiency of PSII (Fv/Fm) of in vitro established leaves decreased gradually from 0.70 directly after taking out of in vitro culture to 0.57 and 0.53 for plants exposed to 75 and 150 μmol m-2 s-1 PPFD, respectively for the first weeks, and then progressively increased to 0.76 at the end of acclimatisation period. The Fv/Fm ratio for new ex vitro established leaves was significantly higher than for the old ones. High Fs (steady state fluorescence) and low vitality index (Rfd) for in vitro established plants were noted at the beginning of acclimatisation and indicate poor functioning of dark phase of photosynthesis. Vitality index of new leaves was about twice as high as the old, in vitro formed ones and reflected their higher photosynthetic potential. The highest vitality index was measured for plants exposed to higher light intensity.

Matysiak B., 2004. Effect of light intensity on growth and chlorophyll fluorescence of Rhododendron microcuttings during acclimatisation. Folia Horticulturae 16/1: 107-114.