Abiotic stress is the negative impact of non-living factors on the living organisms in a specific environment. The non-living variable must influence the environment beyond its normal range of variation to adversely affect the population performance or individual physiology of the organism in a significant way.
A killifish is any of various oviparous (egg-laying) cyprinodontiform fish, including families Aplocheilidae, Cyprinodontidae, Fundulidae, Nothobranchiidae, Profundulidae and Valenciidae. All together, there are 1,270 species of killifish, the biggest family being Rivulidae, containing more than 320 species. As an adaptation to living in ephemeral waters, the eggs of most killifish can survive periods of partial dehydration. Many of the species rely on such a diapause, since the eggs would not survive more than a few weeks if entirely submerged in water. The adults of some species, such as Kryptolebias marmoratus, can additionally survive out of the water for several weeks. Most killies are small fish, from 2.5 to 5 centimetres, with the largest species growing to just under 15 centimetres (6 in).
Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.
Pleopeltis polypodioides, also known as the resurrection fern, is a species of creeping, coarse-textured fern native to the Americas and Africa.
Cytorrhysis is the permanent and irreparable damage to the cell wall after the complete collapse of a plant cell due to the loss of internal positive pressure. Positive pressure within a plant cell is required to maintain the upright structure of the cell wall. Desiccation resulting in cellular collapse occurs when the ability of the plant cell to regulate turgor pressure is compromised by environmental stress. Water continues to diffuse out of the cell after the point of zero turgor pressure, where internal cellular pressure is equal to the external atmospheric pressure, has been reached, generating negative pressure within the cell. That negative pressure pulls the center of the cell inward until the cell wall can no longer withstand the strain. The inward pressure causes the majority of the collapse to occur in the central region of the cell, pushing the organelles within the remaining cytoplasm against the cell walls. Unlike in plasmolysis, the plasma membrane maintains its connections with the cell wall both during and after cellular collapse.
Cryptobiosis or anabiosis is a metabolic state in extremophilic organisms in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all measurable metabolic processes stop, preventing reproduction, development, and repair. When environmental conditions return to being hospitable, the organism will return to its metabolic state of life as it was prior to cryptobiosis.
Selaginella lepidophylla, also known as a resurrection plant, is a species of desert plant in the spikemoss family (Selaginellaceae). It is native to the Chihuahuan Desert of North America and Mexico. S. lepidophylla is renowned for its ability to survive almost complete desiccation. Resurrection plants are vascular rooted plants capable of surviving extreme desiccation, then resuming normal metabolic activity upon rehydration. The plant's hydro-responsive movements are governed by stem moisture content, tissue properties and a graded distribution of lignified cells affecting concentric stem stiffness and spiraling. During dry weather in its native habitat, its stems curl into a tight ball, uncurling only when exposed to moisture.
Poikilohydry is the lack of ability to maintain and/or regulate water content to achieve homeostasis of cells and tissue connected with quick equilibration of cell/tissue water content to that of the environment. The term is derived from Ancient Greek ποικίλος.
A xerophyte is a species of plant that has adaptations to survive in an environment with little liquid water. Examples are typically desert regions like the Sahara, and places in the Alps or the Arctic. Popular examples of xerophytes are cacti, pineapple and some Gymnosperm plants.
Osmoprotectants or compatible solutes are small organic molecules with neutral charge and low toxicity at high concentrations that act as osmolytes and help organisms survive extreme osmotic stress. Osmoprotectants can be placed in three chemical classes: betaines and associated molecules, sugars and polyols, and amino acids. These molecules accumulate in cells and balance the osmotic difference between the cell's surroundings and the cytosol. In plants, their accumulation can increase survival during stresses such as drought. In extreme cases, such as in bdelloid rotifers, tardigrades, brine shrimp, and nematodes, these molecules can allow cells to survive being completely dried out and let them enter a state of suspended animation called cryptobiosis.
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce crop varieties that boast unique and superior traits for a variety of applications. The most frequently addressed agricultural traits are those related to biotic and abiotic stress tolerance, grain or biomass yield, end-use quality characteristics such as taste or the concentrations of specific biological molecules and ease of processing.
Myrothamnus flabellifolius is a plant species in the genus Myrothamnus found in Southern Africa. It is also called the resurrection plant, for the speed with which apparently dead leaves revive when the rains come.
Eragrostis curvula is a species of grass known by the common name weeping lovegrass. Other common names include Boer lovegrass, curved lovegrass, Catalina lovegrass, and African lovegrass.
Jill Farrant, professor of molecular and cell biology at the University of Cape Town, South Africa, is a leading expert on resurrection plants, which 'come back to life' from a desiccated, seemingly dead state when they are rehydrated.
Xerophyta is a plant genus in the family Velloziaceae named in 1789. It is native to Africa, Madagascar, and the Arabian Peninsula.
Haberlea is a monotypic genus of flowering plants in the family Gesneriaceae. The only member of this genus, Haberlea rhodopensis, is endemic to parts of Bulgaria and a small part of northern Greece, especially in the Rhodope Mountains. Common names include Orpheus flower and resurrection plant because of the remarkable ability of Haberlea to survive very long periods of desiccation.
Boea is a genus of plants in the family Gesneriaceae, with species originating from Australia, China, India, Malaysia, Myanmar, Philippines, Polynesia, Solomon Islands, Thailand, Papua New Guinea, Indonesia, Nepal, Bhutan, Cambodia, Vietnam and Laos.
Craterostigma plantagineum, is a resurrection plant species in the genus Craterostigma. It is a dwarf growing plant and can be found to make a 'carpet' across the ground, with blooms in shades of blue and purple. It is a well-studied desiccation-tolerant species known for its extreme vegetative tolerance against dehydration and desiccation. It is native to parts of Africa and to India. It is known as a resurrection plant.
Dorcoceras is a genus of flowering plants in the African violet family Gesneriaceae, native to Assam, Southeast Asia, China and central Malesia. Its species were transferred from the genus Boea in 2016.
Plant cryopreservation is a genetic resource conservation strategy that allows plant material, such as seeds, pollen, shoot tips or dormant buds to be stored indefinitely in liquid nitrogen. After thawing, these genetic resources can be regenerated into plants and used on the field. While this cryopreservation conservation strategy can be used on all plants, it is often only used under certain circumstances: 1) crops with recalcitrant seeds e.g. avocado, coconut 2) seedless crops such as cultivated banana and plantains or 3) crops that are clonally propagated such as cassava, sweet potato.
