Sucrose metabolism in Orobanche and Cuscuta

The scapes of Orobanche cernua were found to be devoid of sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities. Invertase was highly active and was of the “acid” type. Both SS and SPS were active in the filaments of Cuscuta campestris. SS was active in C. reflexa also. In Cuscuta species, invertase was present in “acid” and “neutral” forms. Both in Orobanche and Cuscuta, invertase was essentially in the soluble form. The results indicate that the inability to synthesise sucrose may be a distinctive feature of obligatory parasites.