A nonspecific response of the photosynthetic apparatus of pine needles to industrial air pollution and shading

Abstract

The pigment composition and light-response curves of the indices of prompt chlorophyll fluorescence were investigated in needles sampled from various parts of the tree crown in pine trees growing under natural conditions at various distances from a source of industrial air pollution (a copper-melting works). Shading and pollution decreased the threshold light level of the state corresponding to the second phase of the light-response curve of nonphotochemical chlorophyll fluorescence quenching, increased a nonradiating dissipation of the absorbed light energy, and decreased the rate of electron transfer between PSII and PSI. The patterns thus established demonstrate the existence of nonspecific chloroplast responses to pollution and shading similar in their mechanism, which decrease the efficiency of light energy utilization.