The Salt and Plant, respectively, are the prefix “Halo” and the suffix “Phyte.” As a result, halophytes are frequently referred to as salt-tolerant, salt-loving, or saltwater plants, whereas nearly all of our domesticated crops are glycophytes, having been selected and developed from freshwater ancestors. Various classification schemes have been offered, but Aronson’s (1996) definition is perhaps the simplest and clearest: “Halophyte species are those that only occur in naturally saline circumstances.” Due to the heterogeneity of plant reactions with a variety of circumstances, including climatic conditions and plant phenophases, it’s difficult to exactly distinguish halophytes as opposed to glycophytes. For example, a plant may be sensitive during the germination or seedling phase but tolerant during the other phases, or it may be sensitive to salinity in dry climates but easily overcome it in moist climates.
Halophytes are unusual plants because they can withstand salt concentrations that would kill 99 percent of other species. Plants that “complete the life cycle in a salt concentration of at least 200 mm NaCl under conditions that are comparable to those found in nature” are known as halophytes.
Diversity of Halophytes
Halophytes are uncommon plant forms that evolved separately in unrelated plant families during the diversification of angiosperms. They are comparable in this sense to epiphytes, saprophytes, xerophytes, aquatics, and marsh plants. Because it is difficult to establish the lowest salt tolerance limit at which a plant can be categorized as a halophyte, there is no complete list of halophyte species. Aronson (1989) developed an incomplete halophyte list, which comprised 1560 species spread across 550 genera and 117 families. His list was compiled from research papers and talks with scientists as part of a project to build a global halophyte collection to test for novel crops (Aronson et al., 1988). He utilized a broad definition of halophyte to encompass any plant that was said to be more tolerant than conventional crops, with a maximum salt level of 5 g/l total dissolved solids (TDS) in irrigation water (85 mM as NaCl). His list, however, was limited to plants that could be used as food, forage, fuelwood, or soil stabilization crops.
The apparent adaptations of halophytes to tolerate salts also vary widely (Ungar, 1991). To correlate morphological and physiological features to specific halophyte environments or growth strategies, classification schemes have been developed. Le Houerou (1993) examined three classification approaches for halophytes: four types based on salt tolerance, five types based on ecological associations, and twelve types based on edaphics.
Halophytes can withstand salt. Although many aspects of the physiology of salt tolerance remain unknown, it is clear that the trait is complex in that it necessitates the combination of several traits: the ability to accumulate essential nutrients (particularly K) in the presence of high concentrations of the ions that cause salinity, the accumulation and compartmentation of ions for osmotic adjustment, the synthesis of compatible solutes, and the ability to accumulate essential nutrients (particularly K) in the presence of high concentrations of the ions that cause salinity (Na), and the ability to accumulate essential nutrients (particularly K) in the presence of high concentrations of the (Flowers and Colmer 2008).
Plants have glandular structures that can release a variety of organic substances. Salt secretion, on the other hand, appears to have evolved less frequently than salt tolerance. Salt glands, epidermal appendages of one to a few cells that secrete salt to the plant’s exterior, have been described in only a few orders of Flowering plants– the Poales (e.g. in Aeluropus littoralis and Chloris gayana), Myrtales (e.g. in the mangrove Laguncularia racemosa), Caryophyllales (e (e.g. Cressa cretica). Although there may have been additional independent origins within orders, their distribution across the orders of flowering plants supports at least three origins. It’s uncertain whether salt glands developed from glands that once served a different purpose, although it’s difficult to get glandular hairs on non-halophytes (such as Zea mays L.) to release salt, at least in the Poaceae.
Importance of Halophytes
Land management and Agriculture
Salinity is becoming more of an issue. Moreover, 800 million hectares of land are affected by salt, accounting for more than 6% of the world’s total land area. Vegetation clearing and irrigation, which both raise the water table and bring dissolved salts to the surface, are increasing the amount of salt-affected land on the planet. Salinity is thought to affect up to half of the world’s irrigation networks.
Crops made of halophytes Naturally salt-tolerant species are currently being pushed in agriculture, especially for feed, medicinal plants, aromatic plants, and forestry. Potential oil-seed crops are one example of helpful halophytes. Growing salt-tolerant biofuel crops on marginal agricultural land might help to alleviate fears that the biofuel business is reducing the amount of land available for food production. The fact that dicotyledonous halophytes can grow at rates comparable to glycophytes shows that salt tolerance will not be a limiting factor in output. The difference with drought tolerance is striking here:
Plants cannot grow without water, although they may survive, some plants may thrive in saline water. We may need to rely on halophytes for re-vegetation and cleanup of salt-affected land in the future, in addition to their direct usage as crops. Industrialization has resulted in a massive rise in the production, consumption, and release of heavy metal traces into the environment in Europe and abroad over the previous 200 years. Cd, Cu, Pb, and Zn, for example, accumulate in sediments, especially tidal marsh soils. Some seagrasses and salt marsh plants are capable of collecting heavy metals from sediments and storing them in belowground or aboveground tissues in recent studies. These aquatic halophytes’ processes and prospective applications warrant a lot more investigation and development. Growing salt-tolerant plants, such as Kochia, Bassia, Cynodon, Medicago, Portulaca, Sesbania, and Brachiaria, can improve a variety of soil qualities, including water conductance and soil fertility. Halophytes may also lower the water table, allowing salt-sensitive species to thrive in salt-affected areas.
Food yielding Halophyte and salt-tolerant plants
Beetroot (Beta vulgaris) and Date palm (Phoenix dactylifera) are two traditional crops with high food value that can be produced successfully with saline water irrigation. The Guava (Psidium guajava) and Syzygium cuminii, might be cultivated on alkaline soil (pH up to 9.8) with the use of gypsum supplements in augerholes. The Pomegranate (Punica granatum) is salt-tolerant but not water-resistant. This worked well when cultivated on elevated bunds in alkali soil (pH 10) with kallar grass (Leptochloa fusca), which produced 15-20 Mg/ha fresh feed, and rice (var. CSR-10), which produced up to 4 Mg/ha grains when grown in sunken beds without any amendments. The raw fruits of the kair tree (Capparis decidua) are used to make pickles and have therapeutic properties. It grows in both salty and sodic soils naturally, and it can be grown from rootstocks, seeds, and stem cuttings in a nursery before transplanting. It is possible to irrigate it with saline water. Chenopodium album, Amaranthus species, Portuleca oleracea, Sesuvium portulacastrum, and a variety of other plants are utilized as vegetables and salad in many parts of the country.
The leaves of numerous mangrove and allied plants, such as Avicennia, Ceriops, Rhizophora, Terminalia, Pongamia, and others, are utilized as feed for cattle, goats, and camels in many coastal areas when fodder is scarce. Acacia, Prosopis, Salvadora, Cordia, Ailanthus, and Ziziphus, among other trees, are typical arid-zone fodder plants. Many of these forages may be effectively cultivated on degraded salt-affected soils or in drought-prone areas irrigated with saline water when other arable crops cannot.
Industrial oil production
In dry and semiarid regions, salinity and alkalinity are the two most critical factors limiting agricultural productivity. Most countries cannot afford to reclaim these lands for commercial agriculture. With a shrinking supply of arable farmland and rising demand for food, fiber, and energy, the use of natural salt-resistant species (halophytes) in irrigated and non-irrigated agriculture is becoming increasingly important. Salvadora persica, a facultative halophyte with 40–45 percent oil rich in industrially important lauric (C12) and myrestic (C14) acids, appears to be a potentially valuable oilseed crop for saline and alkali soils. Attempts were made to examine the species’ performance on saline and alkali soils. The findings revealed that the species can be grown in both alkali and salty soils, with saline soil plants having significantly higher height, spread, and seed yield than alkali soil plants. The oil content of seed from plants grown on saline and alkali soils was not significantly different.
Phytoremediation is the cultivation of plants to reduce soil and water pollution (from organic and inorganic contaminants) caused by improper aquaculture, agriculture, and industrial effluent disposal. Phytoremediation is an effective and cost-effective way of eliminating or decreasing contaminants in salt-affected soil. The plants can be collected for selenium-rich animal feed, therefore Salicornia farming could be profitable. Several halophytic types of grass are successful at re-vegetating brine-contaminated soil, which is common in gas and oil extraction.
Question: What is the simple definition of Halophytes?
ANS: Halophytes are frequently referred to as salt-tolerant, salt-loving, or saltwater plants. Halophyte species are those that only occur in naturally saline circumstances.
Question: Where can you find the most Halophytes?
ANS: Halophytes can “complete the life cycle in a salt concentration of at least 200 mm NaCl under conditions that are comparable to those found in nature. The findings revealed that the species can be grown in both alkali and salty soils, with saline soil plants having significantly higher height, spread, and seed yield than alkali soil plants.
Question: What classification do Halophytes have?
ANS: Aronson (1989) developed a Halophyte list, which comprised 1560 species spread across 550 genera and 117 families.