Changes in the geometry of the apical meristem and concomitant changes in cell wall properties during photoperiodic induction of flowering in Chenopodium rubrum

Abstract

Summary• A putative role for local forces at the surface of the apical meristem for plant organogenesis has been postulated in various studies. To correlate changes in morphogenesis to altered local forces, we followed the geometry of the apical meristem during photoperiodic flower induction in Chenopodium rubrum .• The shape of the apical meristem was determined using cryo-scanning electron microscopy. Cell wall properties on the surface of the dome were visualized using uplight polarization microscopy.• A subtle depression at the summit of the apical dome, typical for the vegetative state, became rounded during the early phase of flower induction. The observed changes were quantified as an increase in the ratio of height to diameter of the dome. In parallel, the properties of cell walls on the surface of the dome changed.• The changes in geometry of the apical meristem were attributed to water movement in the meristem paralleled by a change in cell wall properties at the top of the dome. The results support the hypothesis that local changes in surface tension precede initiation of organ primordia.

Determination of floral initiation in Malus domestica: a novel morphogenetic approach

“…Nevertheless, despite high mitotic activity of the shoot apical meristem, its size could not exceed from distinct range. It has been shown that a subtle depression at the summit of the apical dome became rounded during the early phase of flower induction, by which an increase in the ratio of height to diameter of the dome occurs (Albrechtova et al 2004). Our results support the latter findings that are in consensus with the constant cellular context of central zone due to feedback signalling loop between the organising periphery cells and stem cells (Laux et al 1996, Sharma and Fletcher 2002, Sharma et al 2003, Muller et al 2006.…”

“…3E,F) clearly indicate profound tendency towards differentiation during floral initiation. These findings add some new aspects to the previous reports (Albrechtova et al 2004, Kwiatkowska 2004, whose works showed that expansion of the central zone of SAM seems to be isotropic and slower than in the peripheral zone.…”

Invited Review: Cryo-scanning electron microscopy (CSEM) in the advancement of functional plant biology. Morphological and anatomical applications

“…Here, CSEM has revealed the sequence of growth patterns at the apical meristem of Chenopodium rubrum L. (Fig. 1a), where the transition to flowering is marked by the subtle transformation of the apical depression into a convex dome (Albrechtová et al 2004); pollen grains are germinating and sending out pollen tubes to enter the stigma cells of a ragweed (Ambrosia artemisifolia L.) flower (Fig. 1b); spores are poised to detach from the basidia of a mushroom gill (Fig.…”

“…Scale bar = 50 mm. Reproduced from Albrechtová et al (2004) with permission from New Phytologist. (b) Stigma with germinating (arrows) pollen grains of ragweed (Ambrosia artemisifolia).…”

Flower Ontogenesis and Fruit Development of Synsepalum dulcificum

“…Such study has economical and scientific importance especially in botany and agricultural investigations (Dennis et al, 2006;Esumi et al, 2007;Teeri et al, 2006). Floral initiation is an important process in plant development where the plant undergoes physiological and structural changes from the vegetative stage to reproductive stage involving the changes in the apex geometry and inception of the flower primordial (Albrechtova et al, 2004;Jaeger et al, 2006;Kwiatkowska, 2006). With the aid of microscopic techniques, the transition of vegetative primordial to reproductive stage can be detected (Foster et al, 2003;Kurokura et al, 2005;Kwiatkowska, 2006) and scanning electron microscope (SEM) has been used for observation at higher definition in the floral structure and development of fruit crops (Esumi et al, 2007;Foster et al, 2003).…”