Brassica tournefortii | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Brassicales |
Family: | Brassicaceae |
Genus: | Brassica |
Species: | B. tournefortii |
Binomial name | |
Brassica tournefortii Gouan. | |
Brassica tournefortii is a species of plant known by the common names Asian mustard, [1] pale cabbage, [2] African mustard, and Sahara mustard, and is well known as an invasive species, especially in California.
The plant is generally similar to other mustards, but the yellow flowers are not as bright and flashy as closely related species. It is a spreading annual herb with long stems up to 100 centimetres (40 inches) in length.
This mustard is native to the deserts of North Africa and the Middle East. It became notorious during the twentieth century after it invaded the deserts of the United States and Mexico. Recently it has become an abundant weed of low deserts including the Sonoran and Mojave Deserts, plus the desert valleys such as the Coachella and Imperial Valleys of southern California. [3] The plant disperses easily at the first hint of rain. When the seed coats are moistened they form a gel and become very sticky and readily adhere to people, animals, and objects. Seeds easily take hold along roadsides and arid desert lands, especially in disturbed habitats. The plant disperses 750 to 9000 seeds which stay viable for several years in soil, contributing to its status as an invasive species. [4] [5]
Thick stands of the plant can crowd out native flora. Well-adapted to desert life, it monopolizes any moisture in the soil before other plants can get it and forms seeds before other species do. It is particularly an issue in desert farms when the land is tilled. [4]
It produces seed as early in the year as January, especially if the region undergoes a warm spell, which is a common occurrence during southern California winters. It self-fertilizes and drops seeds into the soil, where they persist, survives fires, and long periods without rain. The fact that it propagates by leaving large numbers of viable seeds in the soil prevents eradication measures such as pulling, mowing, grazing and burning. Individual plants have the capacity to separate from the ground and become like tumbleweeds, dropping seeds as they are carried across the desert floor in the breeze. [3]
B. tourneforii outcompetes native plants and monopolizes resources before other plants can acquire them, effectively starving out the competition. The plant also inhibits growth of competition by exhibiting an allelopathic effect on surrounding plants, inhibiting their growth. [6]
Methods of control currently lack biological control, instead physical and preventative measures are taken. Studies are being done that suggests the plant may be controlled using allelopathic methods.[ citation needed ] One study suggests that there are two factors that affect the dormancy of B. tournefortii: one for the removal of the seed coat and another for darkness. The study showed that when the seed coat was removed using NaOCl and placed in dark conditions, germination was increased. This requirement for darkness indicates that B. tournefortii may be less of an issue in farmland where the ground is untilled. [4]
The seeds of B. tournefortii are highly sensitive to certain germination stimulants released by burning vegetation, collectively known as karrikins. [7] Duplication and subsequent evolution of genes encoding the karrikin receptor protein in the B. tournefortii genome is thought to contribute the increased sensitivity to karrikins. [8] In turn, this trait may have enhanced this species' ability to invade after fire events. Control of this species may be improved by exploiting this trait through chemical stimulation of germination, with the aim of clearing the soil seed bank followed by herbicidal applications or physical removal.
B. tournefortii invades sandy soil, particularly deserts. Notably in areas such as Southern California, Northern and Southern Australia, Mexico, etc. [4] [6] [5]
B. tournefortii occupies the 6th position in the national ranking in terms of revenue loss (AU$10.6 million) due to crop yield losses in Australia. [4] [6]
Brassicaceae or Cruciferae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leaves are simple, lack stipules, and appear alternately on stems or in rosettes. The inflorescences are terminal and lack bracts. The flowers have four free sepals, four free alternating petals, two shorter free stamens and four longer free stamens. The fruit has seeds in rows, divided by a thin wall.
In botany, a seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat (testa). More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.
Brassica is a genus of plants in the cabbage and mustard family (Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called cole crops—derived from the Latin caulis, denoting the stem or stalk of a plant.
Plant hormones are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and reproductive development. Unlike in animals each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.
In agriculture, cover crops are plants that are planted to cover the soil rather than for the purpose of being harvested. Cover crops manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in an agroecosystem—an ecological system managed and shaped by humans. Cover crops can increase microbial activity in the soil, which has a positive effect on nitrogen availability, nitrogen uptake in target crops, and crop yields. Cover crops may be an off-season crop planted after harvesting the cash crop. Cover crops are nurse crops in that they increase the survival of the main crop being harvested, and are often grown over the winter. In the United States, cover cropping may cost as much as $35 per acre.
Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial or detrimental effects on the target organisms and the community. Allelopathy is often used narrowly to describe chemically-mediated competition between plants; however, it is sometimes defined more broadly as chemically-mediated competition between any type of organisms. Allelochemicals are a subset of secondary metabolites, which are not directly required for metabolism of the allelopathic organism.
Brassica juncea, commonly brown mustard, Chinese mustard, Indian mustard, leaf mustard, Oriental mustard and vegetable mustard, is a species of mustard plant.
Argemone mexicana is a species of poppy found in Mexico and now widely naturalized in many parts of the world. An extremely hardy pioneer plant, it is tolerant of drought and poor soil, often being the only cover on new road cuttings or verges. It has bright yellow latex. It is poisonous to grazing animals, and it is rarely eaten, but it has been used medicinally by many peoples, including those in its native area, as well as the Natives of the western US, parts of Mexico and many parts of India. In India, during the colorful festival Holika Dahan, adults and children worship by offering flowers, and this species is in its maximum flowering phase during March when the Holi festival is celebrated. It is also referred to as "kateli ka phool" in India.
Striga, commonly known as witchweed, is a genus of parasitic plants that occur naturally in parts of Africa, Asia, and Australia. It is currently classified in the family Orobanchaceae, although older classifications place it in the Scrophulariaceae. Some species are serious pathogens of cereal crops, with the greatest effects being in savanna agriculture in Africa. It also causes considerable crop losses in other regions, including other tropical and subtropical crops in its native range and in the Americas. The generic name derives from Latin strī̆ga, "witch".
White mustard is an annual plant of the family Brassicaceae. It is sometimes also referred to as Brassica alba or B. hirta. Grown for its seeds, it is used to make the condiment mustard, as a fodder crop, or as a green manure. It is now widespread worldwide, although it probably originated in the Mediterranean region.
Sinigrin or allyl glucosinolate is a glucosinolate that belongs to the family of glucosides found in some plants of the family Brassicaceae such as Brussels sprouts, broccoli, and the seeds of black mustard. Whenever sinigrin-containing plant tissue is crushed or otherwise damaged, the enzyme myrosinase degrades sinigrin to a mustard oil, which is responsible for the pungent taste of mustard and horseradish. Seeds of white mustard, Sinapis alba, give a less pungent mustard because this species contains a different glucosinolate, sinalbin.
A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature – either the xylem, phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. This provides them with the ability to extract resources from the host. These resources can include water, nitrogen, carbon and/or sugars. Parasitic plants are classified depending on the location where the parasitic plant latches onto the host, the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plants in approximately 20 families of flowering plants are known.
Arctostaphylos glauca is a species of manzanita known by the common name bigberry manzanita. It is native to California and Baja California, where it grows in the chaparral and woodland of coastal and inland hills.
Mucilage is a thick gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of mucilage. It is a polar glycoprotein and an exopolysaccharide. Mucilage in plants plays a role in the storage of water and food, seed germination, and thickening membranes. Cacti and flax seeds are especially rich sources of mucilage.
Karrikins are a group of plant growth regulators found in the smoke of burning plant material. Karrikins help stimulate seed germination and plant development because they mimic a signaling hormone known as strigolactone. Strigolactones are hormones that help increase growth of symbiotic arbuscular mycorrhizal fungi in the soil, which enhances plant growth and leads to an increase in plant branching.
Parthenium hysterophorus is a species of flowering plant in the family Asteraceae. It is native to the American tropics. Common names include Santa-Maria, Santa Maria feverfew, whitetop weed, and famine weed. In India, it is locally known as carrot grass, congress grass or gajar ghas or dhanura. It is a common invasive species in India, Australia, and parts of Africa.
Brassica elongata, the elongated mustard or long-stalked rape, is a species of the mustard plant that is native to parts of Central Europe, Eastern Europe, the Balkan Peninsula, the Caucasus, Morocco and parts of Central Asia. Through plant invasion this species has become naturalized in many other parts of the world. Some of these naturalized regions include South Africa, North Western Europe, Australia and North America. Given the wide range of climate and ecological conditions of these regions, B. elongata has been able to disrupt the ecosystems of their native plant habitats and has been label as an invasive species in many of its naturalized zones. In North America, this species is often found as a roadside weed in the southwestern states, particularly in the state of Nevada. Studies allude that the Cruciferae might have migrated through the Bering land bridge from what is now Central Asia. Commonly known as the long-stalked rape or as langtraubiger Kohl in German, this species is a close cousin to Brassica napus (rapeseed) and a secondary genetic relative to B. oleracea (kale). As a close genetic species of the rapeseed, the long-stalked rape has one of the highest counts of accumulated polyunsaturated linoleic and linolenic acid. Both compounds are heavily used to manufacture vegetable oils. Brassica elongata has the propagative potential of turning into a horticultural product from what is currently a noxious weed.
Alternaria brassicicola is a fungal necrotrophic plant pathogen that causes black spot disease on a wide range of hosts, particularly in the genus of Brassica, including a number of economically important crops such as cabbage, Chinese cabbage, cauliflower, oilseeds, broccoli and canola. Although mainly known as a significant plant pathogen, it also contributes to various respiratory allergic conditions such as asthma and rhinoconjunctivitis. Despite the presence of mating genes, no sexual reproductive stage has been reported for this fungus. In terms of geography, it is most likely to be found in tropical and sub-tropical regions, but also in places with high rain and humidity such as Poland. It has also been found in Taiwan and Israel. Its main mode of propagation is vegetative. The resulting conidia reside in the soil, air and water. These spores are extremely resilient and can overwinter on crop debris and overwintering herbaceous plants.
June Nasrallah is Barbara McClintock Professor in the Plant Biology Section of the School of Integrative Plant Science at Cornell University. Her research focuses on plant reproductive biology and the cell-cell interactions that underlie self-incompatibility in plants belonging to the mustard (Brassicaceae) family. She was elected to the US National Academy of Sciences in 2003 for this work and her contributions generally to our understanding of receptor-based signaling in plants.
Wisconsin Fast Plants is the registered trademark for a cultivar of Brassica rapa, developed as a rapid life-cycle model organism for research and teaching. Wisconsin Fast Plants are a member of the Brassicaceae family, closely related to the turnip and bok choy. Wisconsin Fast Plants were developed in accordance with an ideotype for an ideal model organism to be used in expediting plant research. Similarly, their rapid life cycle and other model organism characteristics made them easy to grow in large numbers in classrooms. For the last few decades they have been grown in classrooms and laboratories around the world.