Nettle, a Long-Known Fiber Plant with New Perspectives

Abstract

The stinging nettle Urticadioica L. is a perennial crop with low fertilizer and pesticide requirements, well adapted to a wide range of environmental conditions. It has been successfully grown in most European climatic zones while also promoting local flora and fauna diversity. The cultivation of nettle could help meet the strong increase in demand for raw materials based on plant fibers as a substitute for artificial fibers in sectors as diverse as the textile and automotive industries. In the present review, we present a historical perspective of selection, harvest, and fiber processing features where the state of the art of nettle varietal selection is detailed. A synthesis of the general knowledge about its biology, adaptability, and genetics constituents, highlighting gaps in our current knowledge on interactions with other organisms, is provided. We further addressed cultivation and processing features, putting a special emphasis on harvesting systems and fiber extraction processes to improve fiber yield and quality. Various uses in industrial processes and notably for the restoration of marginal lands and avenues of future research on this high-value multi-use plant for the global fiber market are described.

Keywords: Urtica dioica L.; cultivation; fiber production and processing; phylogeny; phytomanagement; stinging nettle.

Figure 1

Graphical representation of historical advances in the development of nettle.

Figure 2

Longitudinal () and disordered () process lines for nettle fiber extraction and separation from 1723 until present.

Figure 3

The morphology of the stinging nettle with focuses on (a) roots, (b) stem section, (c) shoots, (d) leaf, (e) node, (f) female and (g) male flowers, (h) leaf covered with stinging hairs, and (i) stinging hairs on the stem.

Figure 4

Transverse cross-sections of wild nettle stems harvested in Saint-Symphorien (France, Bourgogne-Franche-Comté region (lat. 47°5′5.98″ N. 5°19′44.0322″ E) in 2019 at different times between May (a), June (b), July (c), and August (d). Arrows point out some examples of primary bast fibers (a–c): Placet et al., unpublished data; (d), [11]).

Figure 5

Relative diversity and abundance (%) of the most represented fungal classes (a) and functional groups of fungi (b) associated with the roots of nettle from the Fresnes-sur-Escaut site. The classes with a relative abundance <5% and the less abundant and diverse functional groups have been gathered in the group “others” (Adapted from [123]). Endophytic fungal structures observed by fluorescence (c,d) and photonic (e–g) microscopy in preparations of nettle roots labelled with WGA-AF488 or stained with trypan blue, respectively. (c) fungal hyphae colonizing a cortical cell; (d) network of extracellular fungal hyphae; (e) hyphae forming brain-like microsclerotia; (f) intracellular fungal spores with various morphologies; (g) melanized fully packed microsclerotia (Yung et al., unpublished data).

Figure 6

Nettle stem and bast fiber yield (Mg DM ha⁻¹) as affected by N fertilization and planting density in published peer-reviewed studies listed in Table 2. Dotted line represents linear regression for the data. Data of spontaneous nettle were excluded from the analyses, as well as mean values representing only 1 study in planting densities higher than 7 plants m⁻² [150].

Figure 7

Nettle stem and bast fiber yield (Mg DM ha⁻¹) as affected by years of cultivation in spontaneous and cultivated nettle. Points within boxplots are mean values, while the thick line in the boxplot represents the median value. Data have been obtained for studies collected in the peer-reviewed literature (Table 2) [1,2,4,11,21,140,151,152,153,154,155,156,157,158].

Figure 8

Bast fiber extraction and separation methods for nettle plants (compilation of techniques that graphically illustrate the methods described in the text).