RT Journal Article
SR Electronic
T1 A minimally disruptive method for measuring water potential in-planta using hydrogel nanoreporters
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.05.29.122507
DO 10.1101/2020.05.29.122507
A1 Piyush Jain
A1 Weizhen Liu
A1 Siyu Zhu
A1 Jeff Melkonian
A1 Duke Pauli
A1 Susan Jean Riha
A1 Michael A. Gore
A1 Abraham D. Stroock
YR 2020
UL http://biorxiv.org/content/early/2020/05/30/2020.05.29.122507.abstract
AB Leaf water potential is a critical indicator of plant water status, integrating soil moisture status, plant physiology, and environmental conditions. There are few tools for measuring plant water status (water potential) in situ, presenting a critical barrier for the development of appropriate phenotyping (measurement) methods for crop development and modeling efforts aimed at understanding water transport in plants. Here, we present the development of an in situ, minimally-disruptive hydrogel nanoreporter (AquaDust) for measuring leaf water potential. The gel matrix responds to changes in water potential in its local environment by swelling; the distance between covalently linked dyes changes with the reconfiguration of the polymer, leading to changes in the emission spectrum via Fluorescence Resonance Energy Transfer (FRET). Upon infiltration into leaves, the nanoparticles localize within the apoplastic space in the mesophyll; they do not enter the cytoplast or the xylem. We characterize the physical basis for AquaDust’s response and demonstrate its function in intact maize (Zea mays L.) leaves as a reporter of leaf water potential. We use AquaDust to measure gradients of water potential along intact, actively transpiring leaves as a function of water status; the localized nature of the reporters allows us to define a hydraulic model that distinguishes resistances inside and outside the xylem. We also present field measurements with AquaDust through a full diurnal cycle to confirm the robustness of the technique and of our model. We conclude that AquaDust offers potential opportunities for high-throughput, field measurements and spatially resolved studies of water relations within plant tissues.Competing Interest StatementThe authors have declared no competing interest.