Abstract
The Nitella cell has an extensively granulated protoplasm, measurements on frozen sections giving up to 15% of the total volume of the protoplasm as being made up of nucleii, plastids, mitochondria and non-ergastic bodies. It seems important to inquire whether these granules play a significant role in ion transfers, and indeed, whether these bodies might not be the main seat of ion accumulation.
To determine to what extent the granuloplasm took up ions, single internodal coenocytes 5-10 cm in length of Nitella coronata were prepared by destroying alternate cells in the chain. Care was taken to preserve a short extension of the cellulose wall (about 5 mm long) from the adjacent cell. Surgical thread could then be tied around this cellulose projection and the cell left for 24 hours in pond water in the cold room (15°C) under conditions of intermittent light which simulated sunlight. After this treatment the cell was immersed in radioactive solutions for the desired time and then placed in a centrifuge tube, the thread tied about a cork in the tube and its length adjusted so that the cell was held clear of the sides and bottom of the tube. Centrifugal force sufficient to displace the granules in the cell was applied without any other observable damage. Control centrifuged cells kept under the previous conditions would show a gradual redistribution, reaching substantial completion in about 60 hours, of the stratified granules. These cells lived as long as untreated cells. After stratification had been obtained the experimental cells were bisected into centripetal and centrifugal halves, or fractions, and the activity of each half of the protoplasm measured under a Geiger-Muller counting tube. The only apparent error due to mixing was in the sap, which almost certainly became mixed during the sampling.
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