Factors underlying tip-peaked versus annular wall expansion profiles in tip-growing cells

Determine the mechanistic factors governing whether cell-wall surface expansion strain rates peak at the apex or in an annular region around the apex in tip-growing filamentous cells such as Chara rhizoids, fission yeast, and Medicago truncatula root hairs.

Background

Tip-growing filamentous cells often exhibit distinct spatial patterns of wall surface expansion strain rates. In some species and contexts, the highest strain rates occur at the cell apex, whereas in others they occur in an annular zone surrounding the tip.

The paper motivates its dual-configuration model by highlighting that the determinants of these qualitatively different profiles are not established. It later proposes a mechanistic link between exocytosis distribution, elastic strains, and observed morphology, but the introduction explicitly states the uncertainty regarding the controlling factors.