Soluble polypeptides from root meristems growing at different temperatures.

Soluble polypeptides and their biosynthesis rate have been studied in root meristems of Allium cepa L. bulbs by electrophoresis in SDS polyacrylamide gels. The second mm of the root was chosen in all cases. The polypeptide composition of root meristems growing with a steady state kinetics at 15 degrees C and 25 degrees C appears to be roughly constant. The quantitative differences observed may be due to the different proportion of proliferative cells in the root segments studied, being higher at 15 degrees C than at 25 degrees C. One important fact is the existence of a polypeptide, approximately 80,000 daltons in molecular weight, which appears as an indicator of active proliferation in onion root cells.