Amyloplasts in Slash (Pinus elliottii Engelm.) and Loblolly (Pinus taedaL,.) Pine Rootcaps

摘要

Longitudinal sections revealed that radicles of laboratory-grown slash (Pinus elliottii Engelm.) andloblolly (Pinus taeda L.) pine and lateral roots of naturally-grown and container-grown loblolly pine developeda rootcap that was 3-8 cell layers wide around the root proper at the level of the quiescent center and 8-32 celllayers from the quiescent center to the distal tip. Rootcap cells contained amyloplasts which were locatedmainly in the rootcap center and central columellar cells of the rootcap. Large amyloplasts were located in andaround the rootcap center while small amyloplasts were found in other columellar cells. Amyloplast number perrootcap cell varied with pine species and with how seedlings were grown. There were fewer amyloplasts inradicles than in lateral roots. The spatial distribution of amyloplasts was similar between radicles and lateralroots and they were not found exclusively on the bottom of rootcap cells.