Arrangement of cortical microtubules in the shoot apex of Vinca major L.

Abstract

The arrangements of cortical microtubules (MTs) and of cellulose microfibrils in the median longitudinal cryosections of the vegetative shoot apex of Vinca major L., were examined by immunofluorescence microscopy and polarizing microscopy, respectively. The arrangement of MTs was different in the various regions of the apex: the MTs tended to be arranged anticlinally in tunica cells, randomly in corpus cells, and transversely in cells of the rib meristem. However, in the inner layers of the tunica in the flank region of the apex, cells with periclinal, oblique or random arrangements of MTs were also observed. In leaf primordia, MTs were arranged anticlinally in cells of the superficial layers and almost randomly in the inner cells. Polarizing microscopy of cell walls showed that the arrangement of cellulose microfibrils was anticlinal in tunica cells, random in corpus cells, and transverse in cells of the rib meristem; thus, the patterns of arrangement of microfibrils were the same as those of MTs in the respective regions. These results indicate that the different patterns of arrangement of MTs and microfibrils result in specific patterns of expansion in the three regions. These differences may be necessary to maintain the organization of the tissues in the shoot apex.

On the alignment of cellulose microfibrils by cortical microtubules: A review and a model

“…Close parallelism between microtubules and microfibrils has been found in single cells and filaments; notably, in cotton seed hairs (Itoh 1974b, Willison and Brown 1977, Yatsu and Jacks 1981, Seagull 1986) and spiderwort stamen hairs, including studies which quantified the angular distribution of the orientations of both elements, sometimes in the same cell (Sassen andWolters-Arts 1986, Seagull 1992). Parallelism was also reported for the shoot apical meristem of Vinca major: as viewed in median longitudinal section, in the tunica microtubules and microfibrils are anticlinal, in the rib-meristem both are transverse, and in the corpus both are essentially random (Sakaguchi et al 1988, Sassen et al 1992. Finally, parallelism has been demonstrated quantitatively in roots for the meristem and zone of elongation, locations where the orientations of microtubules and microfibrils are transverse (Mueller and Brown 1982a;Seagull 1983;Hogetsu 1986;Hogetsu and Oshima 1986;Traas and Derksen 1988;Smith-Huerta andJernstedt 1989, 1990;Baskin et al 1999).…”

Changes in the pattern of cell arrangement at the surface of the shoot apical meristem in Hedera helix L. following gibberellin treatment

“…We have shown previously that cortical microtubule arrays in the surface cell layer are parallel to the circumference of the meristem flanks (Marc and Hackett 1989), as in Vinca (Sakaguchi et al 1988a;Selker 1990). In several species the overall alignment of cell-wall microfibrils at meristem flanks is also circumferential (Green 1986;Sakaguchi et al 1988b;Jesuthasan and Green 1989;Nelson 1990).…”

Improvements in immunostaining samples embedded in methacrylate: localization of microtubules and other antigens throughout developing organs in plants of diverse taxa

“…Sakaguchi et al 1988); but this enables study of only the epidermis, and requires non-standard manipulation of the tissue. Another approach has been to use sectioned material.…”