Invertase Development in Storage Tissue 4Beta vulgaris; its Nature, Extent, and Location

The development of invertase activity in storage tissue disksof Beta vulgaris during ageing under aseptic conditions hasbeen studied. The invertase is formed initially in the cellwall and subsequently appears in the cytoplasm. In disks upto 1.0 mm thick, invertase is formed throughout the tissue,but in thicker disks only limited activity appears in the interior.In disks up to 1.0 mm thick, treatment with ethyl acetate priorto enzyme assay increases the measured activity by rendering‘inaccessible’ soluble invertase available to sucrosein the assay medium. In thicker disks, pretreatment with ethylacetate also increases the measured invertase activity by facilitatingsucrose penetration to the centre of the tissue. Osmotic shockaffects invertase activity in the same manner as ethyl acetatetreatment. The significance of these results is discussed inrelation to the induction and development of invertase activityin the disk and in the cell.