Elemental Analysis of a Stinging Nettle Plant using a Dual EDS Detector System

Plants may produce various types of biominerals, consisting of either purely inorganic or variably mineralized composites, where inorganic material is combined with organic compounds. These biominerals tend to play important structural roles and can help us understand how a plant's structure is adapted to its functions and the surrounding environment. 

The composition and distribution of biominerals within a plant sample can be revealed in great detail via SEM EDS spectra and mapping. However, analyzing plants using SEM-based elemental analysis is challenging, as these samples are highly beam-sensitive and tend to show a pronounced topography. Conventional EDS with a single detector requires too high beam currents for plant samples, resulting in specimen damage, electron beam instability and analytical artefacts. 

These problems can be avoided with by using a XFlash 760 double detector system, which facilitates SEM EDS at low kV and low beam current, for plant analysis. 

Here, the trichome of a nettle plant was analyzed using a XFlash 760 double detector system at 6kV and around 800pA probe current. The results show the distribution of the elements Si, Ca, and Mg within the plant's structure. Up to three different biominerals were identified throughout the nettle's single-celled trichomes.

Silicon dioxide, located at the base and tip of the trichome, acts as a hardening agent in the material which can also break easily. Ca- and Mg- based inorganic minerals are more concentrated in the middle section of the trichome where they provide the structure with the flexibility it requires.

Element distribution map by SEM EDS of a stinging nettle plant (Urtica sp.). Charging, shadowing effect and low output count rates can be avoided with an XFlash 760 double detector system.
80 µm x 25 µm HyperMap and complete spectra for each data point of a trichome from a stinging nettle plant (Urtica sp.). The tip and base are enriched in Si (in red), whereas Ca (in blue) and Mg (in green) contents are higher in the middle part of the trichome. The EDS spectra confirm the presence of three different biominerals. The tip and base of the trichome have Si-rich minerals, silicon dioxide acts as a hardening agent in the material but may also break easily when necessary. The rest is made of Ca and Mg-rich minerals, giving the structure the necessary flexibility.