Meetings of the Royal Botanical Society of The Netherlands

The arrangement of cellulose microfibrils (CMFs) is different in various regions of the shoot apex: anticlinal in tunica cells, random in corpus cells and transverse in cells of the rib meristem (Sakaguchi el al. Planla 1988, 175: 403-411). These data are based on examinations of cryosections of Vinca major apices with the polarizing microscope. Careful examination with EM on Petunia and Vinca apices confirmed the above findings for tunica and rib meristem cells, but a different type of CMF arrangement was found for the corpus cells. Apices of Petunia hybrida and Vinca major were fixed with a mixture of p-formaldehyde and glutaraldehyde, and embedded in polyethylene glycol. Longitudinal sections 5 pm in thickness were selected, transferred to nickel oyster grids and extracted with hydrogen peroxide and glacial acetic acid for 30 min at 90°C. After rinsing with water the grids were covered with a forravar film, air-dried, shadowcasted with platinum, and studied with TEM.