Leaf Epidermis: The Ambiguous Symplastic Domain.

The ability to develop secondary (post-cytokinetic) plasmodesmata (PD) is an important evolutionary advantage that helps in creating symplastic domains within the plant body. Developmental regulation of secondary PD formation is not completely understood. In flowering plants, secondary PD occur exclusively between cells from different lineages, e.

Use of CE to Analyze Solutes in Pico- and Nano-Liter Samples from Plant Cells and Rhizosphere.

This chapter describes the use of capillary electrophoresis (CE) in the accurate quantitative mapping of small molecules and ions in intact function tissues between individual cells at single cell resolution. It can also be used for the analysis of the heterogeneity of soil surrounding roots at similar spatial resolution, providing a link between plant and environment. No pretreatment or genetic manipulation of the plant is required.

Aluminium-induced alteration of ion homeostasis in root tip vacuoles of two maize varieties differing in Al tolerance.

Root elongation is a primary target of Al toxicity in plants. The objective of this study was to see whether Al-induced disturbance of ion homeostasis is related to the inhibition of root elongation. For this purpose, root growth rate, free cytoplasmic calcium (Ca²+) and vacuolar content of phosphate (P(i)), potassium (K+), nitrate (NO₃⁻) and malate, as well as malate and citrate exudation and nitrate reductase activity were analysed in tips of two Zea mays L.

Correlation Network Analysis reveals a sequential reorganization of metabolic and transcriptional states during germination and gene-metabolite relationships in developing seedlings of Arabidopsis.

Background: Holistic profiling and systems biology studies of nutrient availability are providing more and more insight into the mechanisms by which gene expression responds to diverse nutrients and metabolites. Less is known about the mechanisms by which gene expression is affected by endogenous metabolites, which can change dramatically during development. Multivariate statistics and correlation network analysis approaches were applied to non-targeted profiling data to investigate transcriptional and metabolic states and to identify metabolites potentially influencing gene expression during the heterotrophic to autotrophic transition of seedling establishment.

Long-distance movement of Cauliflower mosaic virus and host defence responses in Arabidopsis follow a predictable pattern that is determined by the leaf orthostichy.

Long-distance virus transport takes place through the vascular system and is dependent on the movement of photoassimilates. Here, patterns of symptom development, virus movement and gene expression were analysed in Arabidopsis following inoculation with Cauliflower mosaic virus (CaMV) on a single leaf. Virus accumulation and expression of markers for the salicylic acid (SA) and ethylene/jasmonate (Et/JA) defence pathways, PR-1 and PDF1.

Components of Arabidopsis defense- and ethylene-signaling pathways regulate susceptibility to Cauliflower mosaic virus by restricting long-distance movement.

We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling to infection by Cauliflower mosaic virus (CaMV). Mutants cpr1-1 and cpr5-2, in which SA-dependent defense signaling is activated constitutively, were substantially more resistant than the wild type to systemic infection, implicating SA signaling in defense against CaMV. However, SA-deficient NahG, sid2-2, eds5-1, and pad4-1 did not show enhanced susceptibility.

Phloem loading in two Scrophulariaceae species. What can drive symplastic flow via plasmodesmata?

To determine the driving forces for symplastic sugar flux between mesophyll and phloem, gradients of sugar concentrations and osmotic pressure were studied in leaf tissues of two Scrophulariaceae species, Alonsoa meridionalis and Asarina barclaiana. A. meridionalis has a typical symplastic configuration of minor-vein phloem, i.

Turgor, solute import and growth in maize roots treated with galactose.

It has been observed that extension growth in maize roots is almost stopped by exposure to 5 mm d-galactose in the root medium, while the import of recent photoassimilate into the entire root system is temporarily promoted by the same treatment. The aim of this study was to reconcile these two apparently incompatible observations. We examined events near the root tip before and after galactose treatment since the tip region is the site of elongation and of high carbon deposition in the root.

THE PRESSURE PROBE: A Versatile Tool in Plant Cell Physiology.

This review discusses how the pressure probe has evolved from an instrument for measuring cell turgor and other water relations parameters into a device for sampling the contents of individual higher plant cells in situ in the living plant. Together with a suite of microanalytical techniques it has permitted the mapping of water and solute relations at the resolution of single cells and has the potential to link quantitatively the traditionally separate areas of water relations and metabolism. The development of the probe is outlined and its modification to measure root pressure and xylem tension described.

Biosensor reporting of root exudation from Hordeum vulgare in relation to shoot nitrate concentration.

The aim of this study was to determine the relationship between shoot nitrate concentration, mediated by nitrate supply to roots, and root exudation from Hordeum vulgare. Plants were grown for 14 d in C-free sand microcosms, supplied with nutrient solution containing 2 mM nitrate. After this period, three treatments were applied for a further 14 d: (A) continued supply with 2 mM nitrate (zero boost), (B) supply with 10 mM nitrate (low boost), and (C) supply with 20 mM nitrate (high boost).

Rubisco small subunit, chlorophyll a/b-binding protein and sucrose:fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light.

We describe a highly efficient two-step single-cell reverse transcriptase-polymerase chain reaction technique for analyzing gene expression at the single-cell level. Good reproducibility and a linear dose response indicated that the technique has high specificity and sensitivity for detection and quantification of rare RNA. Actin could be used as an internal standard.

Distribution of actin gene isoforms in the Arabidopsis leaf measured in microsamples from intact individual cells.

The contents of single plant cells can be sampled using glass microcapillaries. By combining such single-cell sampling with reverse transcription-polymerase chain reaction (RT-PCR), transcripts of individual genes can be identified and, in principle, quantified. This provides a valuable technique for the analysis and quantification of the intercellular distribution of gene expression in complex tissues.

Changes in osmotic and turgor pressure in response to sugar accumulation in barley source leaves.

Pressure-probe measurements and single-cell sampling and analysis techniques were used to determine the effect of photosynthetic production and accumulation of sugars on osmotic and turgor pressures of individual cells of barley ( Hordeum vulgare L.) source leaves. In control plants, the changes in osmotic pressure in individual cells during the photoperiod were different for mesophyll (increase of 276 mOsmol/kg), parenchymatous bundle sheath (PBS; increase of 100 mOsmol/kg) and epidermis (remains constant).