Development of a sampling protocol for collecting leaf surface material for multiphase chemistry studies.

Area of Science:

• Environmental chemistry
• Plant science
• Atmospheric science

Background:

• Plant leaf surfaces interact with atmospheric oxidants, influencing trace gas exchange and air pollution damage.
• Understanding the chemical composition of leaf surface water is crucial for atmosphere-biosphere interactions.
• Limited knowledge of the sources and nature of leaf surface chemicals complicates sampling strategies.

Purpose of the Study:

• To investigate how sampling variables and environmental factors influence the quantity and composition of water-soluble material on wet leaves.
• To propose a flexible protocol for collecting water-soluble material from wet leaves.
• To characterize the chemical nature of leaf soaks and compare them to authentic raindrops and microbial dissolved organic matter.

Main Methods:

• Leaf soaks were collected using varying solvent volumes and contact times.
• Environmental parameters such as rain, plant location, and plant metabolism were considered.
• UV-vis absorption spectroscopy was used to analyze the chemical composition of leaf soaks.

Main Results:

• Solute concentration in leaf soaks is significantly influenced by the solvent-to-leaf area ratio, contact time, and environmental factors.
• UV-vis spectra of leaf soaks showed similarities to authentic raindrops and microbial dissolved organic matter.
• Leaf soak organic matter exhibited low aromaticity, low chromophore content, and low average molecular weight.

Conclusions:

• A flexible sampling protocol for collecting water-soluble material from wet leaves was developed.
• The findings support hypotheses regarding the amount, origin, nature, and reactivity of water-soluble organics on wet leaves.
• This research opens new avenues for interdisciplinary studies on plant-atmosphere interactions and air pollution effects.