Cytochemical and Ultrastructural Observations on Chenopodium Amaranticolor Hair, Supplied with low and High Sodium Chloride Molarity

SUMMARY

Chenopodium amaranticolor leaves have been supplied with low and high molarity of NaCl. The ultrastructure of the foliar hair shows a cytoplasmic vesiculation when the leaves have been treated with high molarity of NaCl in the light. A similar feature has been described for halophyte salt gland cells. Cytoplasmatic vesicles cannot be observed in dark conditions. PTAC stain, selective for plasmalemma, demonstrated that, in high molarity conditions in the light, some PTAC-positive vesicles are present in the stalk cell, but that they are much less numerous than those detected with the normal counterstain. This may suggest that plasmalemma is not involved in cytoplasmatic vesiculation. Cytochemical detection for Cl⁻ ions shows that in the stalk cell the precipitates do not particularly occur in the cytoplasm but that they are present on the whole plasmalemma profile, inside some vesicles close to it and in correspondence of plasmodesmata. These observations would indicate that at least a part of ion transport occurs in an apoplastic space. The massive accumulation of reaction products can be observed inside the vacuole of the bladder cell, sometimes associated with an electron dense material. Some vesicles interested by precipitates are merging with the bladder cell peripheral plasmalemma suggesting a partial ion secretion. Cl⁻ ion transport seems to be a light dependent process as in dark conditions the number of precipitates diminishes. Na ⁺ transport is likewise dependent on light but it occurs through the cytoplasm of the stalk cell. In fact the cytochemical localisation gives reaction products inside the cytoplasm, the endoplasmatic reticulum and some cytoplasmatic vesicles. Na⁺ ion storage mainly occurs in the stalk cell vacuole.