Field methods for sampling and storing nectar from flowers with low nectar volumes

Area of Science:

• Botany
• Plant Physiology
• Biochemistry

Background:

• Nectar sampling and storage methods are not well-established for flowers with low nectar volumes (<1 microL).
• This study investigates optimal techniques for collecting and preserving nectar from such flowers, using Eucalyptus species as a model.

Purpose of the Study:

• To evaluate different nectar sampling techniques for low-volume flowers.
• To assess various storage conditions and the efficacy of antimicrobial agents for preserving nectar samples.
• To determine the impact of collection and storage on nectar sugar composition and ratios.

Main Methods:

• Compared microcapillary tubes, filter paper blotting, washing, and rinsing for nectar sugar recovery.
• Evaluated storage at room temperature, refrigeration, and freezing, with and without benzyl alcohol or methanol.
• Analyzed nectar samples for sucrose, glucose, and fructose using high-performance liquid chromatography.

Main Results:

• Washing and rinsing were the most effective sampling methods, with no significant difference between them.
• Sugar concentrations changed rapidly during storage; refrigeration without additives yielded stable results for at least 2 weeks.
• Sugar ratios remained stable for up to 4 weeks with methanol/refrigeration or freezing, and 2 weeks with refrigeration alone.

Conclusions:

• Recommends washing for field nectar collection from low-volume flowers, acknowledging potential underestimation of total sugars.
• Emphasizes immediate analysis of sugar mass post-collection.
• Advises caution in selecting collection and storage methods due to significant variability and suggests evaluating their accuracy.