Leaf phosphate status and photosynthesis in vivo: Changes in light scattering and chlorophyll fluorescence during photosynthetic induction in sugar beet leaves

Abstract

Light scattering and chlorophyll fluorescence were measured in vivo for leaves of sugar beet plants cultured with low levels of phosphate (P). Light scattering during photosynthetic induction was markedly increased in low-P compared to control leaves. This effect was reversible, disappearing within 24 h after the P supply was increased. The fluorescence induction curves also exhibited significant and reversible differences between low-P and control leaves. The changes in light scattering and chlorophyll fluorescence correlated well with changes in the rate of photosynthesis in vivo. We suggest that the increase in light scattering during induction in low-P plants may be due to a decreased ability of the Calvin cycle to utilize assimilatory power generated photochemically.