Salicornia, also commonly known as pickleweed, glasswort, sea asparagus and samphire, derives its name from the Latin word meaning “salt” and includes strictly halophytes. Salicornia species thrive in littoral and coastal salt marsh or in inland salt pans, forming distinct vegetation types subjected to different flooding regimes with brackish-to-saline water (depending on tidal influences) and usually composed of almost monospecific plant communities; in general, annual Salicornia occur in the innermost parts of the salt marshes, subject to longer periods of submersion. Asssregards their taxonomy, two series have been traditionally identified, diploid and tetraploid, each of them with numerous species and micro-species. Only three entities are recognized in the Mediterranean: Salicornia procumbens subsp. procumbens (tetraploid, distributed along Mediterranean and Atlantic coasts and including Salicornia emerici, Salicornia veneta and Salicornia dolichostachya), Salicornia perennans subsp. perennans (diploid, with Mediterranean and Eurasian distribution, including Salicornia patula) and Salicornia europaea subsp. europaea (diploid, western Mediterranean). They are almost all of food interest, because of herbaceous in consistency, and the tender tips of the young branches, that are harvested during summer and thean prepared i numerous recipes based on geographic area of interest. Being therophytes, the only method of propagation is by the generative way (from seeds). Salicornia sp. pl. is cultivated on a commercial scale in Israel and in Mexico, the United Arab Emirates, Saudi Arabia and India. In many parts of the Europe, the use of this halophyte is mainly based on the harvesting of wild plants, while only in the Netherlands, Portugal and France are the plants of Salicornia sp. pl. cultivated. In Italy, the first attempts of S. patula cultivation for family consumption started over 40 years ago in the gardens located around the Lesina lagoon (Apulia, Southern Italy). Like other halophilic species, even in glassworts the stress of the alkaline environment induces the synthesis of metabolites that can be useful to humans for their antioxidant and anti-inflammatory power.
1. Brief Description, Distribution and Ecology
Salicornia
, also commonly known as pickleweed, glasswort, sea asparagus and samphire, derives its name from the Latin word meaning “salt” and includes strictly halophytes. These species grow usually at the edges of wetlands, salt marshes and mudflats world-wide. Along with the perennial
Salicornia
sp.pl. and other perennial succulent Amaranthaceae/Chenopodiaceae, they thrive in littoral and coastal salt marsh or in inland salt pans, forming distinct vegetation types subjected to different flooding regimes with brackish-to-saline water (depending on tidal influences) and usually composed of almost monospecific plant communities. In general, annual
Salicornia
species occur in the innermost parts of the salt marshes, subject to longer periods of submersion. This group of species is characterized by succulent and articulated stems with opposite pairwise-fused leaves and bracts and inconspicuous flowers with three-flowered cymes in which the lateral flowers are in contact below the central flower. The green plant turns orange, pink to reddish in autumn, before dying in winter
[1]
[2]
.
In general, the taxonomic identity of the
Salicornia species is a challenging issue. The complexity of the genus
Salicornia in Europe has produced many reversals, alternating partitions within the genus. As regards the annual
Salicornia species, two series have been traditionally identified, diploid and tetraploid, each of them with numerous species and micro-species. Only three entities are recognized in the Mediterranean:
Salicornia procumbens subsp.
procumbens (tetraploid, distributed along Mediterranean and Atlantic coasts and including
Salicornia emerici,
Salicornia veneta and
Salicornia dolichostachya),
Salicornia perennans subsp.
perennans (diploid, with Mediterranean and Eurasian distribution, including
Salicornia patula) and
Salicornia europaea subsp.
europaea (diploid, western Mediterranean)
[3].
In the Apulia region, four species have been recognized: the diploid
S. patula Duval-Jouve (
Figure 12a,b), and the tetraploid
S. emerici Duval-Jouve,
S. veneta Pignatti & Lausi and
S. dolichostachya Moss (
Figure 23a), often very similar morphologically to each other and distinguishable with certainty only if observed in full maturity (flowering and fruiting period). These species typically grow forming the pioneer coastal or continental vegetation of maritime and inland salt marshes, occupying those sites with the highest salt concentration, generally positioned in the first-line belt of the flooding zonation (
Figure 12b and
Figure 23b) on raw soils from sandy to loamy or clay, depending on sedimentation conditions and in large part are poor in nutrients, temporarily flooded and drying out in summer (
Thero-Salicornietea Tx. in Tx. & Oberd. 1958;
Salicornion patulae Géhu & Géhu-Franck 1984;
Salicornion venetae Tomaselli et al. 2020). The phenological optimum is late summer to autumn
[4]. According to the 92/43/EEC “Habitat” Directive, this vegetation falls within the habitat of community interest 1310—“
Salicornia and other annuals colonizing mud and sand”.
Figure 12.
A specimen of
Salicornia patula
(
a
);
S. patula
community ((
b
); the reddish glasswort carpet) at the edge of a coastal lagoon in Salento.
Figure 23.
Salicornia dolichostachya
(
a
); a plant community dominated by
S. dolichostachya
and
S. emerici
(
b
) at “Palude La Vela”, Taranto, southern Apulia).
2. Food Use
The annual glassworts are almost all of food interest. Like other chenopods such as
Sarcocornia perennis,
S. fruticosa and
Arthrocaulon macrostachyum recently introduced for human consumption
[5],
S. patula and other annuals are also an excellent candidate due to the mineral content. Actually, they are little known in the territories of southern Salento where, due to the rocky nature of the coasts, temporary salt ponds and salt marshes have sporadic presence and very limited extent. On the contrary, annual glassworts are widely used in the areas characterized by coastal salt marshes (e.g., Gargano, Capitanata, Brindisi and Taranto areas). The plants are low and herbaceous in consistency, and the tender tips of the young branches are easily broken by hand. The most abundant harvest is in spring, before the reproductive stage begins. The collected tips are cleaned, washed and boiled. After having drained them, one by one, the fleshy green part is removed (like a glove) and the central woody part is thrown away. They can be dressed with oil and lemon or vinegar, put in jars in oil or vinegar or frozen and used as needed. In the area of “Mar Piccolo”, near Taranto, in summer it is used to mix the sea asparagus with leavened dough, which is then portioned and fried (“pettole”). Recently, in the Gargano area it is common to find pizzas or pasta topped with sea asparagus (
Figure 34 and
Figure 45c;
Table 1). In recent years, the sale of sea asparagus in oil or in vinegar has spread in various locations in northern Apulia (especially Gargano) and in the Bari area, even in large-scale distribution.
Figure 34. Distribution, across the Apulia region, of the food use of various halophytes (included Salicornia sp. pl.) and halotolerant species, according to our field observations and literature data.
Figure 45.
Salicornia
sp. sold at a fish shop (
a
) and at a superstore (
b
) in Bari; a dish of pasta with
Salicornia
sp. (
c
); Peschici, Gargano, Northern Apulia).
Table 1.
Summary of the main features of various halophytes and halotolerant species, included
Salicornia
sp. pl.
In the Iberian Peninsula and France,
S. emerici has long been largely consumed as food
[6]. In South Korea, tender
Salicornia shoots are processed in drinks such as nuruk (a type of fermentation initiator), makgeolli (a Korean rice wine) or vinegar
[7]; the aerial parts are used in salads, and their consumption is a source of salt in the diet
[8].
3. Domestication/Cultivation
Being therophytes, the only method of propagation is by the generative way (from seeds). The seeds are located in a bract cavity, unprotected, so they fall as they reach maturity. It is necessary to be timely in collecting the parts that have already matured the seeds and to be careful not to drop them during the cutting and bagging operations. The quantity of seeds collected per plant is always minimal. Recently, interest towards
Salicornia sp. has risen dramatically, especially in the Gargano area where some attempts of medium-scale cultivations have been run
[9].
In Israel,
Salicornia and
Sarcocornia cultivation for vegetable production is typically practiced under simple nets or in greenhouses on land areas of 0.5–1 ha. For the products of these crops to be successfully marketed as vegetables, the young shoots must be harvested manually, an intensive element critical to halophyte crop production. Different cultivation protocols, therefore, have been tested for
Salicornia vegetable production.
Salicornia sp. pl. is cultivated on a commercial scale in Israel and in Mexico, the United Arab Emirates, Saudi Arabia and India. In many parts of the Europe, the use of this halophyte is mainly based on the harvesting of wild plants, while only in the Netherlands, Portugal and France are the plants of
Salicornia sp. pl. cultivated. In Italy, the first attempts of
S. patula cultivation for family consumption started over 40 years ago in the gardens located around the Lesina lagoon (Apulia, Southern Italy). After only a few years, some local farmers started the cultivation of this wild grass as a cash crop, due to the increasing interest in this food, the attractive price and the possibility of economic profits from the cultivation of marginal lands
[10].
In Apulia, harvesting in open fields takes place in July–August. In Israel, it is from August–September, and it is carried out manually in order to maintain the high quality of the final product; only fresh and tender parts can be sold (
Figure 45a,b).
Salicornia can be collected several times during the year in greenhouses. The harvesting can be repeated every two or three weeks (depending on the level of development). Plants are cut above 5 cm from the ground at a height of 10–15 cm. This repeated harvesting enables the same plant to be cut from three-to-four times, depending on the level of growth. The yield can reach 10–15 tons per hectare
[11].
4. Other Uses/Properties
Like other halophilic species, even in glassworts the stress of the alkaline environment induces the synthesis of metabolites that can be useful to humans for their antioxidant and anti-inflammatory power
[12]. For example, bioactive compounds such as phenols and fatty acids have been isolated for
S. patula, and it has been found that the concentration of these compounds depends greatly on how close the plants are to the sea. Caffeic, coumaric, salicylic and trans-cinnamic acids and flavonoids, such as quercetin-3-O-rutinoside, kaempferol/luteolin, apigenin 7-glucoside and pelargonidin-3-O-rutinoside, have been isolated. Furthermore, high concentrations of palmitic, oleic and linoleic acids have been found
[13].