Extensor and Flexor Protoplasts from Samanea Pulvini

Abstract

Concentrations of K, Cl, P, S, and Ca in extensor and flexor protoplasts from open pulvini of the nyctinastic tree S. saman were estimated using X-ray microanalysis. This technique is particularly suitable when absolute numbers of protoplasts are low, because < 100 protoplasts are required to obtain statistically significant data. Flexor protoplasts contain similar concentrations of P and S but almost twice as much K and Cl as extensor protoplasts. Low levels of total measurable osmoticum suggest that extensive leakage has occurred during protoplast isolation. Both extensor and flexor protoplasts apparently contain some unidentified osmoticum not detectable by X-ray analysis. Extensor protoplasts must have more unidentified osmoticum to compensate for their lower levels of K and Cl.