ANATOMY OF SWOLLEN RACHIS AND ITS EFFECTS ON BERRY GROWTH OF MUSCAT OF ALEXANDRIA GRAPES

Abnormal swelling of the rachis of 'Muscat of Alexandria' grapevines g rown in a heated glasshouse was investigated. The swelling became appa rent at the peduncular node or along the rachis three to four weeks af ter full bloom. Berry growth was inhibited thereafter with the degree of inhibition varying among clusters. Anatomical studies revealed that a mass of small parenchyma cells divided among or around the phloem t issue two to four weeks after anthesis, which stymied further developm ent of sieve tubes. Numerous granules (0.5 approximately 2.0 mum in di am.) were observed in these meristematic cells under SEM.