Water Adsorption to Leaves of Tall Cryptomeria japonica Tree Analyzed by Infrared Spectroscopy under Relative Humidity Control

Introductory biology lessons around the world typically teach that plants absorb water with their roots, but, unfortunately, absorption of water through leaves and subsequent transport and use of this water for biomass formation remains a field limited mostly to specialists. Recent studies have identified foliar water uptake as a significant net water source for terrestrial plants. The growing interest in the development of a new model that includes both foliar water uptake (in liquid form) and root water uptake to explain hydrogen and oxygen isotope ratios in leaf water and tree rings demands a method for distinguishing between these two water sources. I therefore devised a labelling method that utilizes two different water sources, one enriched in deuterium (HDO + D2O; δD = 7.0 × 104‰, δ18O = 4.1‰) and one enriched in oxygen-18 (H218O; δD = −85‰, δ18O = 1.1 × 104‰), to simultaneously label both foliar-absorbed and root-absorbed water and quantify their relative contributions to plant biomass. Using this new method, I here present evidence that, in the case of well-watered Cryptomeria japonica, hydrogen and oxygen incorporated into new leaf cellulose in the rainy season derives mostly from foliar-absorbed water (69% from foliar-absorbed water and 31% from root-absorbed water), while that of new root cellulose derives mostly from root-absorbed water (20% from foliar-absorbed water and 80% from root-absorbed water), and new branch xylem is somewhere in between (55% from foliar-absorbed water and 45% from root-absorbed water). The dual labelling method first implemented in this study enables separate and simultaneous labelling of foliar-absorbed and root-absorbed water, and offers a new tool to study the uptake, transport, and assimilation processes of these waters in terrestrial plants.

show abstract

Foliar water uptake as a source of hydrogen and oxygen in plant biomass

Kagawa

2020

Preprint

View full text Add to dashboard Cite

The assumption that hydrogen and oxygen of plant biomass originate almost exclusively from water absorbed by roots (Farquhar et al., 1998; Roden et al., 2000; McElrone et al., 2013), has long been taken for granted in plant sciences. However, recent studies have also identified foliar water uptake as a significant but still unquantified net water source for terrestrial plants (Eller et al., 2013; Goldsmith et al., 2013; Dawson & Goldsmith, 2018; Berry et al., 2019; Schreel & Steppe, 2020). The growing interest in the development of a new model that includes foliar water uptake to explain hydrogen and oxygen isotope ratios in leaf water and tree rings requires a method for distinguishing between these two water sources. I therefore devised a method utilizing two different heavy waters (HDO and H218O) to simultaneously label both foliar-uptake water and root-uptake water and quantify their relative contributions to plant biomass. Using this new method, I here present evidence that, in the case of well-watered Cryptomeria japonica, hydrogen and oxygen incorporated into new leaf cellulose in the rainy season derives mostly from foliar-uptake water, while that of new root cellulose derives mostly from root-uptake water, and new branch xylem is somewhere in between. Abandoning the assumption that these elements are supplied from soil water alone may have vast implications in fields ranging from isotope dendroclimatology, silviculture, to biogeochemistry.

show abstract

Water Adsorption to Leaves of Tall Cryptomeria japonica Tree Analyzed by Infrared Spectroscopy under Relative Humidity Control

Cited by 3 publications

References 62 publications

Terahertz spectroscopy for quantification of free water and bound water in leaf

Terahertz spectroscopy for quantification of free water and bound water in leaf

Foliar water uptake as a source of hydrogen and oxygen in plant biomass

Foliar water uptake as a source of hydrogen and oxygen in plant biomass

Contact Info

Product

Resources

About