Measuring intracellular Ca2+ levels in plant cells using the fluorescent probes, indo-1 and fura-2: Progress and prospects

Abstract

Recent advances in the development of methods for measuring cytoplasmic Ca2+ levels in higher plant cells are discussed. Emphasis is placed on the new generation of Ca2+-sensitive fluorescent dyes particularly fura-2 and indo-1. These dyes offer many advantages for the measurement of cytosolic Ca2+ levels. They can be introduced into cells in a nonintrusive manner, their Kd for Ca2+ matches plant cell cytoplasmic Ca2+ levels, and shifts in their emission (indo-1) or excitation (fura-2) spectra following Ca2+ binding permit accurate quantitation of Ca2+ activities. Examples of cytoplasmic Ca2+ levels measured in plants with fura-2 and indo-1 are presented, and the prospects for applying more advanced technologies to fluorescent dye measurement are discussed.