Positioning the Root Elongation Zone Is Saltatory and Receives Input from the Shoot

Abstract

Summary In the root, meristem and elongation zone lengths remain stable, despite growth and division of cells. To gain insight into zone stability, we imaged individual Arabidopsis thaliana roots through a horizontal microscope and used image analysis to obtain velocity profiles. For a root, velocity profiles obtained every 5 min over 3 h coincided closely, implying that zonation is regulated tightly. However, the position of the elongation zone saltated, by on average 17 μm every 5 min. Saltation was apparently driven by material elements growing faster and then slower, while moving through the growth zone. When the shoot was excised, after about 90 min, growth zone dynamics resembled those of intact roots, except that the position of the elongation zone moved, on average, rootward, by several hundred microns in 24 h. We hypothesize that mechanisms determining elongation zone position receive input from the shoot.

Physiological Mechanism through Which Al Toxicity Inhibits Peanut Root Growth

“…Moreover, ABA inhibits cell division and differentiation of stem cells, thereby restraining the growth of primary roots in plants [ 21 , 22 ]. GA regulates the area size of the root meristem in plants and is particularly important for GA biosynthesis in the cortex and inner cortex [ 23 , 24 ]. GA at the root tip stimulates the development and proliferation of root cells [ 24 , 25 ].…”

Integrative Roles of Phytohormones on Cell Proliferation, Elongation and Differentiation in the Arabidopsis thaliana Primary Root

“…In the EZ the cells do not divide and can increase their length three times in only 3 h ( Verbelen et al, 2006 ; Salvi et al, 2020 ; Figure 1 ). Recently, it was discovered that in seedlings where the shoot is removed, the EZ is displaced toward the root tip, indicating that the aerial part of the plant can send signals to maintain root growth ( Baskin et al, 2020 ). In addition, hormones regulate the expression and function of enzymes that participate in cell wall modifications in the EZ similarly to what happened in TD cells ( Wu and Cosgrove, 2000 ; Somssich et al, 2016 ; Barbez et al, 2017 ; Dietrich, 2018 ).…”

Data_Sheet_1.PDF

“…In the EZ the cells do not divide and can increase their length three times in only 3 h (Verbelen et al, 2006;Salvi et al, 2020; Figure 1). Recently, it was discovered that in seedlings where the shoot is removed, the EZ is displaced toward the root tip, indicating that the aerial part of the plant can send signals to maintain root growth (Baskin et al, 2020). In addition, hormones regulate the expression and function of enzymes that participate in cell wall modifications in the EZ similarly to what happened in TD cells (Wu and Cosgrove, 2000;Somssich et al, 2016;Barbez et al, 2017;Dietrich, 2018).…”