Hormonal regulation of stem cell maintenance in root meristems of Arabidopsis thaliana

Continuing root growth is crucial for the ongoing survival of a plant and provides the structure basis for the acquisition of valuable resources such as water and nutrients required for growth and development. The root apical meristem, located at the root apex, contains a stem cell niche which is the source of root cell production and patterning. This project focuses on the influence of phytohormone signalling upon the maintenance of the root apical meristem (RAM) in Arabidopsis thaliana. Through a combination of physiological, genetic and molecular approaches, the project has uncovered evidence of the involvement of three plant hormones, auxin, abscisic acid (ABA) and ethylene, in regulating the differentiation of stem cells and their descendants in Arabidopsis root meristems. Key findings include: 1) exogenous application of auxin, ABA or 1-aminocyclopropane-1-carboxylic acid (ACC), which is an ethylene precursor, rescues the root meristem failure of a1f3-1 seedlings; 2) exogenous application of ABA promotes QC quiescence and suppresses stem cell differentiation in wild type Arabidopsis root meristems; 3) inhibition of ethylene biosynthesis and mutations that cause ethylene insensitivity induce differentiation of stem cells in root meristems and.i.on the other hand, exogenous application of ethylene precursor or mutations causes ethylene over-production suppress stem cell differentiation in Arabidopsis root meristems; 4) ABA and ethylene interact antagonistically with auxin in the regulation of both stem cell differentiation in Arabidopsis root meristem, and the expression of the CLE40 gene, which encodes a negative regulator of stem cell differentiation in root meristems; 5) ABA modulates the abundance of the LM6 arabinan cell wall epitope within at the root meristem; 6) ethylene suppresses the stem cell differentiation in Arabidopsis root meristems induced by nitrogen (N) and phosphorus (P) deficiencies. The results of the project demonstrate that stem cell regulation in Arabidopsis root meristems involves complex interactions of plant hormones and environmental signals.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Hormonal regulation of stem cell maintenance in root meristems of Arabidopsis thaliana

Continuing root growth is crucial for the ongoing survival of a plant and provides the structure basis for the acquisition of valuable resources such as water and nutrients required for growth and development. The root apical meristem, located at the root apex, contains a stem cell niche which is the source of root cell production and patterning. This project focuses on the influence of phytohormone signalling upon the maintenance of the root apical meristem (RAM) in Arabidopsis thaliana. Through a combination of physiological, genetic and molecular approaches, the project has uncovered evidence of the involvement of three plant hormones, auxin, abscisic acid (ABA) and ethylene, in regulating the differentiation of stem cells and their descendants in Arabidopsis root meristems. Key findings include: 1) exogenous application of auxin, ABA or 1-aminocyclopropane-1-carboxylic acid (ACC), which is an ethylene precursor, rescues the root meristem failure of a1f3-1 seedlings; 2) exogenous application of ABA promotes QC quiescence and suppresses stem cell differentiation in wild type Arabidopsis root meristems; 3) inhibition of ethylene biosynthesis and mutations that cause ethylene insensitivity induce differentiation of stem cells in root meristems and.i.on the other hand, exogenous application of ethylene precursor or mutations causes ethylene over-production suppress stem cell differentiation in Arabidopsis root meristems; 4) ABA and ethylene interact antagonistically with auxin in the regulation of both stem cell differentiation in Arabidopsis root meristem, and the expression of the CLE40 gene, which encodes a negative regulator of stem cell differentiation in root meristems; 5) ABA modulates the abundance of the LM6 arabinan cell wall epitope within at the root meristem; 6) ethylene suppresses the stem cell differentiation in Arabidopsis root meristems induced by nitrogen (N) and phosphorus (P) deficiencies. The results of the project demonstrate that stem cell regulation in Arabidopsis root meristems involves complex interactions of plant hormones and environmental signals.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Struvite: a slow-release fertiliser for sustainable phosphorus management

Background and Aim: Recycled sources of phosphorus (P), such as struvite extracted from wastewater, have potential to substitute for more soluble manufactured fertilizers and help reduce the long-term threat to food security from dwindling finite reserves of phosphate rock (PR). This study aimed to determine whether struvite could be a component of a sustainable P fertiliser management strategy for arable crops.Methods: A combination of laboratory experiments, pot trials and mathematical modelling of the root system examined the P release properties of commercial fertiliser-grade struvite and patterns of P uptake from a low-P sandy soil by two different crop types, in comparison to more soluble inorganic P fertilisers (di-ammonium phosphate (DAP) and triple super phosphate (TSP)). Results: Struvite had greatly enhanced solubility in the presence of organic acid anions; buckwheat, which exudes a high level of organic acids, was more effective at mobilising struvite P than the low level exuder, spring wheat. Struvite granules placed with the seed did not provide the same rate of P supply as placed DAP granules for early growth, but fertiliser mixes containing struvite and DAP applied to spring wheat demonstrated optimal early P-uptake and higher rates of P-fertiliser recovery.Conclusions: We conclude that the potential resource savings and efficiency benefits of utilising a recycled slow release fertiliser like struvite offers a more sustainable alternative to only using conventional, high solubility, PR-based fertilisers.?<br/