SALSOLA KALI: CHARACTERISTICS, TAXONOMY, HABITAT, DISTRIBUTION - BIOLOGY - 2025

Salsola kali is a herbaceous plant belonging to the Amaranthaceae family. It is commonly known as Texas ball, Russian thistle, spiky bush, globetrotter, or tumbleweed, among others.

It is an annual herbaceous plant with an erect stem that later develops a globose shape. It has small leaves of up to 2 cm and the bracts end in spines. The fruits and seeds are dispersed by the action of the wind, because this plant breaks from the root and forms rolling spheres in the fields where it grows.

Dried Texas ball plant. Source: wikimedia commons

It grows in dry or desert areas and saline soils. It is native to Europe and Asia, but has been accidentally introduced elsewhere, mixed with seeds of other species. Currently it is considered a very invasive species with a great dispersal capacity.

As a curious fact, Salsola kali is the plant that is observed rolling on the ground in famous cowboy movies. It produces hives with the friction of its flower bracts.

The Russian thistle is used as a forage species in the areas where it lives. Its cultivation could be used for recovery plans for soils contaminated with metals such as cadmium, since this plant bioaccumulates this element without suffering from the toxicity that it generally produces to other plant species.

characteristics

Plant

It is an annual herbaceous plant, with a spherical or globose shape, highly branched stems from the basal part to the middle part, devoid of pubescence and is about 120 cm high.

Leaves

Its leaves are simple and alternate. Those in the lower part are between 1 - 2 cm long by 0.2 - 0.3 cm in width, and the leaves in the upper part are between 0.5 - 0.8 cm long; It has bracts that end in spines.

Salsola kali spines. Source: wikimedia commons

flowers

The flowers can be solitary or grouped between 2 or 3, and they sprout in the axils of the leaves of the upper part of the plant.

The flower is composed of 5 ovate tepals with a cartilaginous texture when mature. They are pinkish or greenish-white in color.

Fruit

The fruit of this herb is dry and dehiscent, measures 1.5 mm long, its apex is concave and around it pieces of the tepals are preserved.

Seed

The fruit contains a shiny black seed in a horizontal position, with a conical-spiral shape and measures 1.8 - 2.2 mm long and 1.4 - 1.6 mm wide.

The dispersion of the seeds occurs together with the entire plant, once the wind breaks from the root and rolls traveling long distances, at the same time that it releases its fruits and therefore its seeds.

A plant can produce up to 150,000 and 200,000 seeds; reason for which it has high dispersal and invasion capacity.

Taxonomy

-Kingdom: Plantae

-Class: Equisetopsida

-Subclass: Magnoliidae

-Superorden: Caryophyllanae

-Order: Caryophyllales

-Family: Amaranthaceae

-Gender: Salsola

-Species: Salsola kali L. 1753

The basionym of this species is Salsola kali subsp. Iberian. Some of its synonyms are: Salsola australis, Salsola australis var. strobilifera, Salsola brachypteris, Salsola kali subsp. ruthenica, Salsola kali var. brachypteris, Salsola kali var. leptophylla, Salsola tragus.

Habitat and distribution

The Texas ball is native to Europe and Asia. However, it inhabits xerophytic areas and is commonly seen in the desert area of ​​northern Mexico and the southwestern United States, where very little rain normally falls.

It is considered a fairly invasive species that was accidentally introduced, mixed with the seeds of cultivable species.

It grows in dry or desert environments, and as a weed in some crops. Its location on the edge of the roads constitutes a problem, because it can surprise drivers and cause road accidents. Interestingly, this plant also grows in soils contaminated with radioisotopes.

Salsola kali in its desert habitat. Source: wikimedia commons

It thrives on saline soils, infrastructure such as railways, roads, and residential or abandoned buildings.

Ecological and economic impact

This herb invades arid or semi-arid ecosystems, having been reported as an invasive species in Argentina, Chile, Australia and North American countries such as Canada and the United States.

The growth of this herb in livestock maintenance places increases the costs of its management, because the animals do not graze in the places invaded by this plant.

Texas ball pollen can cause some allergic reactions. Floral bracts pierce the skin, cause hives, and lead to dermatitis.

While, the nitrates and oxalates accumulated in the photosynthetic organs of this plant produce intoxication in sheep.

Detail of branches and flowers of Salsola kali. Source: wikimedia commons

This species can host the insect Circulifer tenellus (hemiptera), a vector of viruses that attack important crops such as tomato; in this way they affect production and cause agricultural economic losses.

In contrast to the negative effects it produces, Salsola kali has been shown to be a phytoaccumulator of cadmium, a heavy metal that is toxic to many animals and plants.

According to studies, the roots, stems and leaves of this plant accumulate this element and produce greater biomass compared to other species for which cadmium is phytotoxic during its growth; In this way, the tumbleweed could be useful for soil phytoremediation plans.

Control

This invasive species can be controlled mechanically, chemically, or with cultural work. For this, the production of seeds through the plow must be avoided in the areas infested by this pest.

You can also pass the harrow or rake when this grass is a few cm high, or by pruning the plants before the fruiting period.

Salsola kali seedling. Source: Krzysztof Ziarnek, Kenraiz

In addition, it can be controlled by burning in the autumn season, preventing more seeds from dispersing when the individuals begin to break.

For its part, chemical control allows to control this weed with the application of pesticides (herbicides) 2,4-D, MCPA (phenothiol) and 2,4-DB.

Applications

Salsola kali is used as a forage plant for animals in the desert or arid areas. This practice has increased its expansion and invasion in areas where it does not naturally inhabit.

This plant helps, as required, to quickly spread the fire thanks to its morphology, which allows maximum air circulation.

In the future, it is expected to use this plant as a phytoremediator of contaminated soils due to its bioaccumulative properties of heavy metals such as cadmium.

References

1. De la Rosa, G., Peralta-Videa, J., Montes, M., Parsons, J., Cano-Aguilera, I., Gardea-Torresdey, J. 2004. Cadmium uptake and translocation in tumbleweed (Salsola kali), a potential Cd-hyperaccumulator desert plant species: ICP / OES and XAS studies. Chemosphere 55 (9): 1159-1168.
2. Chiuffo, M. 2016. Salsola kali L. In: Manual of Invasive Plants of South America. I. Herrera, E. Goncalvez, A. Pauchard, R. Bustamante (eds). Trama Impresores SA page. 14-15.
3. Argentine National Pest Surveillance and Monitoring System. 2019. Salsola kali. Taken from: sinavimo.gov.ar
4. Tropics. 2019. Salsola kali L. taken from: tropicos.org
5. Rapid Invasivity Assessment Method (MERI) for exotic species in Mexico. 2019. Salsola kali subsp. tragus L., 1753. Taken from: gob.mx
6. USDA. Fire Effects Information System (FEIS). 2019. Species: Salsola kali. Taken from: fs.fed.us