There is no change in Ca levels between Arabidopsis leaves at 27 and 37 DAG. Also, there appears to be little Ca mobilization from senescing leaves of wheat or pea (Hocking
1994, Marschner 1995). This is consistent with the observa- tion that Ca is not mobile in the phloem (Bukovac and Wittwer
1957). However, despite its apparent immobility in phloem, Ca does appear to