Biology subjects

Salvalaio, M.

Publications and source records attributed to Salvalaio, M..

3 recordsLinked to original sources

bioRxiv2025

Patterned 3D-printed hydrogel as a novel soilless substrate for plant cultivation

Plant roots need water, micronutrients, and oxygen to maintain cellular metabolism and tissue growth, yet traditional hydroponic systems often lack sufficient oxygen delivery. While 3D printing artificial substrates has been explored to mimic the physical structure of soil, it remains unclear which design parameters are critical for supporting full plant development. Here, we present a synthetic, soilless substrate based on 3D-printed hydrogels incorporating triply periodic minimal surface (TPMS) patterns to create internal air-filled channels. These channels are open to the atmosphere, enabling passive gas exchange throughout the substrate. We tested five TPMS geometries (Lidinoid, Split-P, Schwarz-D, Schwarz-P, and Schoen), each with a near-identical hydrogel volume but with different surface-to-volume ratios. Arabidopsis thaliana seeds germinated directly on the substrates and were monitored for vegetative and reproductive growth over five weeks. Among the designs, the Lidinoid substrate led to the highest number and surface area of leaves, exceeding the aerated hydroponic control in leaf area over most of the time course; it also produced the earliest and most complete flowering, which neither control achieved in the same amount of time. Our results indicate that the surface-to-volume ratio is a key parameter influencing substrate performance; we hypothesise that this reflects its effect on oxygen availability at the root interface, which we did not measure directly. Plants grown on substrates with higher surface areas transitioned to flowering more reliably and rapidly, with flowering efficiency showing a strong positive correlation with surface area. These findings suggest that interconnected air-channel architectures can support full plant development without active aeration, potentially by overcoming the oxygen limitations of traditional hydroponic systems. This work supports the use of additive manufacturing as a powerful tool for engineering soil analogues tailored for indoor agriculture. By combining passive aeration with hydration and nutrient delivery, patterned hydrogels offer a promising, scalable solution for sustainable soilless plant cultivation.

plant biology↗

bioRxiv2023

Long-term root electrotropism reveals habituation and hysteresis

Plant roots sense many physical and chemical cues in soil, such as gravity, humidity, light and chemical gradients, and respond by redirecting their growth towards or away from the source of the stimulus. This process is called tropism. While gravitropism is the tendency to follow the gravitational field downwards, electrotropism is the alignment of growth with external electric fields and the induced ionic currents. Although root tropisms are at the core of their ability to explore large volumes of soil in search of water and nutrients, the molecular and physical mechanisms underlying most of them remain poorly understood. We have previously provided a quantitative characterization of root electrotropism in Arabidopsis (Arabidopsis thaliana) primary roots exposed for 5 hours to weak electric fields, showing that auxin asymmetric distribution is not necessary but that cytokinin biosynthesis is. Here, we extend that study showing that long-term electrotropism is characterized by a complex behavior. We describe overshoot and habituation as key traits of long-term root electrotropism in Arabidopsis and provide quantitative data about the role of past exposures in the response to electric fields (hysteresis). On the molecular side, we show that cytokinin, although necessary for root electrotropism, is not asymmetrically distributed during the bending. Overall, the data presented here represent a significant step forward towards the understanding of the molecular mechanisms regulating electrotropism in plants and provide a quantitative platform for future studies on the genetics of this and other tropisms.

plant biology↗

bioRxiv2020

Root electrotropism in Arabidopsis does not depend on auxin distribution, requires cytokinin biosynthesis and follows a power-law response curve

An efficient foraging strategy for plant roots relies on the ability to sense multiple physical and chemical cues in soil and to reorient growth accordingly (tropism). Root tropisms range from sensing gravity (gravitropism), light (phototropism), water (hydrotropism), touch (thigmotropism) and more. Electrotropism, also known as galvanotropism, is the phenomenon of aligning growth with external electric fields and currents. Although observed in a few species since the end of the 19th century, the molecular and physical mechanism of root electrotropism remains elusive, limiting the comparison to more defined sensing pathways in plants. Here we provide a first quantitative and molecular characterisation of root electrotropism in the model system Arabidopsis thaliana, showing that it does not depend on an asymmetric distribution of the plant hormone auxin, but that instead it requires the biosynthesis of a second hormone, cytokinin. We also show that the dose-response kinetics of the early steps of root electrotropism follows a power law analogous to the one observed in some physiological reactions in animals. A future full molecular and quantitative characterisation of root electrotropism would represent a step forward towards a better understanding of signal integration in plants, and an independent outgroup for comparative analysis of electroreception in animals and fungi.

plant biology↗