Comparison of Plastids and Pigments of Pinus palustris Mill. and Pinus-elliottii Engelm. in Callus Tissue Culture

Abstract

Summary Callus cultures of two closely related pine species, Pinus palustris Mill. and Pinus elliottii Engelm., initiated from hypocotyl explants and grown under identical cultural conditions on the same chemically defined medium are strikingly different in pigmentation and plastid development. P. palustris maintains a deep green color throughout healthy callus growth, whereas P. elliottii quickly loses its initial green color and grows vigorously as a friable yellow-white callus. Acetone extracts of pigments from P. palustris callus contain quantifiable levels of chlorophylls and carotenoids, but the amount of pigments contained in comparable extracts of P. elliottii callus is practically nil. Typical grana as found in normal green leaves were not observed in either species, however green callus cells of P. palustris commonly contain plastids possessing 2–4 thylakoids in stacks. The plastids observed in the typically yellow-white callus cells of P. elliottii were devoid of thylakoid structures.