Flowers under pressure: ins and outs of turgor regulation in development.

Léna Beauzamy,Naomi Nakayama,Arezki Boudaoud

doi:10.1093/aob/mcu187

Abstract

BackgroundTurgor pressure is an essential feature of plants; however, whereas its physiological importance is unequivocally recognized, its relevance to development is often reduced to a role in cell elongation.ScopeThis review surveys the roles of turgor in development, the molecular mechanisms of turgor regulation and the methods used to measure turgor and related quantities, while also covering the basic concepts associated with water potential and water flow in plants. Three key processes in flower development are then considered more specifically: flower opening, anther dehiscence and pollen tube growth.ConclusionsMany molecular determinants of turgor and its regulation have been characterized, while a number of methods are now available to quantify water potential, turgor and hydraulic conductivity. Data on flower opening, anther dehiscence and lateral root emergence suggest that turgor needs to be finely tuned during development, both spatially and temporally. It is anticipated that a combination of biological experiments and physical measurements will reinforce the existing data and reveal unexpected roles of turgor in development.

Highlights

ROLES OF TURGOR PRESSUREPlants are made of tiny ‘pressure bombs’
In order to assess the role of turgor pressure and its regulation, it is fundamental to obtain quantitative data on water potential, hydrostatic pressure, osmotic pressure and hydraulics, which we review in the following
Despite the widely held dogma that turgor pressure is uniform in all cells of an organ, cells are equipped with machinery to create differential turgor pressure

Summary

INTRODUCTION

Plants are made of tiny ‘pressure bombs’. walled cells as in plants, fungi or bacteria contain a high hydrostatic pressure termed turgor pressure. Turgor pressure is often thought to be uniform within a developing organ, it can be variable from cell to cell It can change dynamically depending on many intrinsic and extrinsic factors, such as sugar metabolism, changes in the shapes of cells and tissues (including growth) and environmental conditions. Turgor pressure provides structural integrity to each cell and to the tissue as a whole (Fig. 1). It is believed that the outermost structure of aerial organs is under tension and withstands the internal pressure (Peters and Tomos, 1996; Hamant and Traas, 2010; Robinson et al, 2013); the pressure exerted from the internal cells is borne by the epidermal cells – especially the outermost cell wall on the tissue surface (Fig. 1B). 4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited

B Tissue tension

B Pressure chamber

B Cell behaviour under osmotic treatment

C Pollen tube growth

Findings

DISCUSSION