Immunolocalization of calreticulin in protoplasts and somatic embryos of Daucus carota L. grown in suspension culture

Ca2+ acts as a second messenger which controls a wide variety of cellular f unctions. Ca2+ homeostasis is accomplished by a complex of mechanisms inclu ding pumps, ion channels and calcium buffers within storage compartments. C alreticulin is the low-affinity, high-capacity Ca2+-binding protein of most eucaryotic cells. The distribution of calreticulin was studied in isolated protoplasts and during different stages of somatic embryogenesis in carrot (Daucus carota L. cv. St Valery Lunga Rossa) suspension culture. Immunoflu orescence staining of protoplasts showed the presence of calreticulin in th e cytoplasm. No calreticulin was observed within vacuoles. During somatic e mbryogenesis calreticulin was distributed mainly in the protoderm of develo ping embryos in different stages.