68 publications from this institution
Protoplasts were isolated from developing xylem of Pinusbanksiana Lamb, and Pinusstrobus L. by incubating freshly harvested tissue in a cellulose–pectinase mixture having mannitol as osmoticum. Protoplasts were then purified using a discontinuous sucrose–mannitol gradient. More than 70% of the isolated protoplasts were of small diameter (12–27 μm) and had dense cytoplasm and many small vacuoles, suggesting that they originated from ray cells. Larger protoplasts constituted about 25% of the protoplast population; these contained single large vacuoles and only parietal cytoplasm, suggesting that they originated from fusiform cells. Using combined gas chromatography–mass spectrometry, coniferin was confirmed to be present in protoplast preparations. By high-performance liquid chromatography (258 nm UV detection), coniferin was readily detected in protoplasts and in extracts of developing xylem from both species. On a fresh-weight basis, coniferin occurred at 1.0–1.6 mM in protoplasts. In late June, coniferin in developing xylem could be accounted for totally by protoplast coniferin content. In late July, protoplasts contained 93 and 61% of the coniferin content in developing xylem of P. strobus and P. banksiana, respectively.
Tree mortality is becoming more common in wild forests, plantations, and orchards. Remedial or preventative counteracting measures are limited because, before the onset of overt dying, reliable methods to distinguish intrinsically healthy trees from unhealthy trees are lacking. Survivotypes within dead populations can nevertheless be identified and conserved in support of achieving suitably adapted future forests.
