1,721,151 research outputs found
Does the degree of pectin esterification influence aluminium sorption by the root apoplast?
No full textAbstract This study investigates the influence of the
degree of pectin esterification (DE) on the sorption of
aluminium (Al) by plant roots. Ca-pectates, with
varying degrees of esterification, are major constituents
of the soil–root interface and of the root apoplast. Capectate
networks (Ca–PG and Ca–Al–PG) were formed
at three DEs (0%, 26%, 65%) with custom-made cells
and used as a model system for the root cell wall.
Sorption of Al was conducted for 24 h at a range of
oxalic acid concentrations (0–500 μM) at pH 4.50 to
examine two different metal resistance mechanisms of
plants. In fact, plants release organic acids either to
desorb or to complex metals to prevent their sorption by
plant roots.Thermal analysis showed that Al sorption
did not seem to affect the stability of the pectate gels and
the presence of hydrophobic groups (–CH3) at DE>0%
seemed to even increase the stability of the gels
decreasing thermal decomposition. Results suggest
two potential Al tolerance mechanisms: (a) high oxalic
acid concentrations (500 μM) were able to desorb
almost 100% and 72% at DE 65 and 0%, respectively;
(b) high oxalic acid concentrations (500 μM) and thus
molar ratios of 5:1 (oxalate/Al) reduced Al sorption by
98% and 86% at DE 65 and 0%, respectively. In
conclusion, both mechanisms indicate that high
degrees of esterification as 65% are much more
efficient in excluding Al from the apoplast and might
therefore contribute to Al resistance in plants
Dynamics, thermodynamics and kinetics of exudates: crucial issues in understanding rhizosphere processes
No full textBackground: In this issue, Schenkeveld and coworkers described the potential of phytosiderophores (a class of root exudates) to mobilize metals in the rhizosphere by an equilibrium modelling approach.
Scope: The rhizosphere is a complex and dynamic environment where several different organic and inorganic compounds coexist. Due to the different concentration and chemical characteristics there might be competitive and synergistic interactions. However the rhizosphere is strongly influenced by root activity: water and nutrient uptake, root respiration that might modify the pH and redox status of the rhizosphere. Thus, how does the complexity of the system and the dynamics influence the thermodynamics of the single process? Can chemical equilibria be really reached in the rhizosphere? Issues related to kinetics vs thermodynamics are discussed. The study of the single processes is important but more complex researches, being thus more realistic (i.e. field-like conditions), are necessary. Hence, what are the available tools/methods in rhizosphere research? What are the drawbacks? How can the results of these methods be related to thermodynamic and kinetic models?
Conclusions: Besides stimulating further awareness around the rhizosphere complexity, tentative answers are given highlighting the future challenges in rhizosphere research, essential knowledge for the development of agronomic practices ensuring a better exploitation of soil endogenous resources of nutrients by crops
Tendril-based climbing plants to model, simulate and create bio-inspired robotic systems
No full textBioinspiration can be considered one of the keys for future smart and versatile robotic systems. Plants could be an important source of ideas despite the fact that they have not yet been deeply observed and considered. In this paper, climbing tendril-bearer plants that, by means of irritable filiform organs called tendrils, search for a support, grasp it and climb to gain height, have been used to study and develop an effective climbing robot. The study aimed first to evaluate the main movements and behaviors of the tendril from a biomimetic point of view. The tendril complexity was then simplified, a robotic model was developed and a kinematic simulator was designed and implemented to visualize and evaluate the chosen system. Finally, based on the biological, technical and numerical evaluations, the main tendril behaviors were replicated by proof of concept devices made of smart materials to move towards a practical realization and to replicate the simulated results. The designed proof of concept prototypes showed good repeatability and feasibility
Phosphorus deficiency changes carbon isotope fractionation and triggers exudate reacquisition in tomato plants
Full text linkPlant roots are able to exude vast amounts of metabolites into the rhizosphere in response to phosphorus (P) deficiency. Causing noteworthy costs in terms of energy and carbon (C) for the plants. Therefore, it is suggested that exudates reacquisition by roots could represent an energy saving strategy of plants. This study aimed at investigating the effect of P deficiency on the ability of hydroponically grown tomato plants to re-acquire specific compounds generally present in root exudates by using 13C-labelled molecules. Results showed that P deficient tomato plants were able to take up citrate (+ 37%) and malate (+ 37%), particularly when compared to controls. While glycine (+ 42%) and fructose (+ 49%) uptake was enhanced in P shortage, glucose acquisition was not affected by the nutritional status. Unexpectedly, results also showed that P deficiency leads to a 13C enrichment in both tomato roots and shoots over time (shoots—+ 2.66‰, roots—+ 2.64‰, compared to control plants), probably due to stomata closure triggered by P deficiency. These findings highlight that tomato plants are able to take up a wide range of metabolites belonging to root exudates, thus maximizing C trade off. This trait is particularly evident when plants grew in P deficiency. © 2020, The Author(s)
Accumulation of aluminium at the soil-root interface
No full textIl contributo fornisce dati relativamente all'accumulo d'alluminio all'interfaccia suolo/radice in funzione del grado di metil-esterificazione delle pectine constituenti la parete cellulare e l'apoplasto. Sono discusse implicazioni relative ai meccansimi di tolleranza alla tossicità dell'alluminio
Mobilizzazione di metalli tossici da un pectato di calcio utilizzato come modello d’interfaccia suolo-radice: ruolo del grado di metil-esterificazione del pectato
No full text
Involvement of two MATE genes in the release of root exudates in apple plants grown under nutrient deficiency
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