Biology subjects

Busch, F. A.

Publications and source records attributed to Busch, F. A..

3 recordsLinked to original sources

bioRxiv2025

Cytosolic water potential as a mechanistic driver of leaf airspace unsaturation and non-stomatal control of transpiration

1Mesophyll cells exhibit a previously underappreciated capacity to regulate water loss via low plasma membrane conductance (Lp), offering a non-stomatal mechanism for transpiration control. However, the structural basis and regulation of Lp remain poorly understood, limiting its integration into predictive models. In this study, we show that Lp responds dynamically to changes in cytosolic water potential ({psi}cy), decreasing as{psi} cy approaches the turgor loss point. This identifies{psi} cy as the primary physiological signal regulating Lp. We introduce a predictive, physiologically grounded model linking Lp to{psi} cy. Our model establishes a mechanistic connection between internal water status, leaf hydraulics, substomatal cavity unsaturation, and gas exchange. This framework opens new avenues for understanding and modelling plant water use under stress.

plant biology↗

bioRxiv2025

Evidence for active regulation of transpiration in non-stomatal plants

O_LIBryophyta (mosses) are a basal group of plants that lack stomata in their haploid form, as well as developed vascular tissue and a hydrophobic cuticle. Consequently, these plants are classified as poikilohydric, meaning poor control over water loss and are often assumed to reach equilibrium with ambient humidity. This classification does not fully align with the diverse strategies observed in mosses. C_LIO_LIWe studied gas exchange in 14 species from Albuquerque and Boston, USA, under controlled dehydration conditions. C_LIO_LIOur results revealed significant variation in transpiration rates, cell wall equilibrium humidity, and desiccation times across species. These differences could not be explained by tissue water storage relative to the transpiring surface area, suggesting that water loss is not entirely passive. Additionally, species with better water control also presented traits of an avoidance strategy, including elastic tissues, high capacitance, and less negative osmotic potential, suggesting an adaptive constraint. C_LIO_LIThese findings point to a basal, non-stomatal mechanism of water loss control through cell membranes and/or cell walls. Potentially, this mechanism is homologous to the non-stomatal control recently identified in angiosperms, which induces unsaturated conditions in the substomatal cavities. Bryophyta presents a valuable non-stomatal model for further investigating this mechanism and its evolutionary significance. C_LI

plant biology↗

bioRxiv2022

A cross-scale analysis to understand and quantify effects of photosynthetic enhancement on crop growth and yield

Photosynthetic manipulation provides new opportunities for enhancing crop yield. However, understanding and quantifying effectively how the seasonal growth and yield dynamics of target crops might be affected over a wide range of environments is limited. Using a state-of-the-art cross-scale model we predicted crop-level impacts of a broad list of promising photosynthesis manipulation strategies for C3 wheat and C4 sorghum. The manipulation targets have varying effects on the enzyme-limited (Ac) and electron transport-limited (Aj) rates of photosynthesis. In the top decile of seasonal outcomes, yield gains with the list of manipulations were predicted to be modest, ranging between 0 and 8%, depending on the crop type and manipulation. To achieve the higher yield gains, large increases in both Ac and Aj are needed. This could likely be achieved by stacking Rubisco function and electron transport chain enhancements or installing a full CO2 concentrating system. However, photosynthetic enhancement influences the timing and severity of water and nitrogen stress on the crop, confounding yield outcomes. Strategies enhancing Ac alone offers more consistent but smaller yield gains across environments, Aj enhancement alone offers higher gains but is undesirable in less favourable environments. Understanding and quantifying complex cross-scale interactions between photosynthesis and crop yield will challenge and stimulate photosynthesis and crop research. Summary StatementLeaf-canopy-crop prediction using a state-of-the-art cross-scale model improves understanding of how photosynthetic manipulation alters wheat and sorghum growth and yield dynamics. This generates novel insights for quantifying impacts of photosynthetic enhancement on crop yield across environments.

plant biology↗