Abstract
Plant root growth is enabled by root meristems that harbor the stem cell niches as a source of progenitors for the different root tissues. Understanding the root development of diverse plant species is important to be able to control root growth in order to gain better performances of crop plants. In this study, we analyzed the root meristem of the fourth most abundant crop plant, barley (Hordeum vulgare). Cell division studies revealed that the barley stem cell niche comprises a Quiescent Center (QC) of around 30 cells with low mitotic activity. The surrounding stem cells contribute to root growth through the production of new cells that are displaced from the meristem, elongate and differentiate into specialized root tissues. The distal stem cells produce the root cap and lateral root cap cells, while cells lateral to the QC generate the epidermis, as it is typical for monocots. Endodermis and inner cortex are derived from one common initial lateral to the QC, while the outer cortex cell layers are derived from a distinct stem cell. In rice and Arabidopsis, meristem homeostasis is achieved through feedback signaling from differentiated cells involving peptides of the CLE family. Application of synthetic CLE40 orthologous peptide from barley promotes meristem cell differentiation, similar to rice and Arabidopsis. However, in contrast to Arabidopsis, the columella stem cells do not respond to the CLE40 peptide, indicating that distinct mechanisms control columella cell fate in monocot and dicot plants.
Highlights
The root system of cereal crops from the family of Poaceae like barley, maize and rice is composed of different types of roots formed during consecutive developmental stages
Morex consists of 2–6 seminal roots that arise during the course of the first five days after germination (DAG)
Primary root growth is enabled by root meristems at the tip of the roots, which harbor the stem cell niche that provides the precursors for the various root tissues
Summary
The root system of cereal crops from the family of Poaceae like barley, maize and rice is composed of different types of roots formed during consecutive developmental stages. The primary root primordium and the primordia of seminal roots are initiated (Luxová, 1986). The primary root is initiated below the scutellar node, while the seminal roots are formed later above the scutellar node from the mesocotyl. Primary root growth depends on cell division and expansion. Meristematic cells at the root tip are small and divide rapidly several times before they are displaced from the meristem. They enter a phase in which they cease division and start to rapidly elongate and differentiate (elongation-differentiation zone) (reviewed in Ivanov and Dubrovsky, 2013). In Arabidopsis thaliana, the number of cells in the meristem increases after germination, until the meristem reaches its final size when the rates of cell division and the rate at which cells exit the meristem into the elongation-differentiation zone are balanced (Dello Ioio et al, 2007)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
