Mesophyte

Last updated March 26, 2024

Mesophytes are terrestrial plants which are neither adapted to particularly dry nor particularly wet environments. An example of a mesophytic habitat would be a rural temperate meadow, which might contain goldenrod, clover, oxeye daisy, and Rosa multiflora . Mesophytes prefer soil and air of moderate humidity and avoid soil with standing water or containing a great abundance of salts. They make up the largest ecological group of terrestrial plants, and usually grow under moderate to hot and humid climatic regions.^[1]^[2]

Morphological adaptations

Mesophytes do not have any specific morphological adaptations. They usually have broad, flat and green leaves; an extensive fibrous root system to absorb water; and the ability to develop perennating organs such as corms, rhizomes and bulbs to store food and water for use during drought.^{[ citation needed ]}

Anatomical adaptations

Mesophytes do not have any special internal structure. Epidermis is single layered usually with obvious stomata. Opening or closing of stomata is related to water availability. In sufficient supply of water stromata remain open while in limited supply of water stomata are closed to prevent excessive transpiration leading to wilting.^{[ citation needed ]}

Properties

Mesophytes generally require a more or less continuous water supply. They usually have larger, thinner leaves compared to xerophytes, sometimes with a greater number of stomata on the undersides of leaves. Because of their lack of particular xeromorphic adaptations, when they are exposed to extreme conditions they lose water rapidly, and are not tolerant of drought. Mesophytes are intermediate in water use and needs. These plants are found in average conditions of temperature and moisture and grow in soil that has no water logging. The roots of mesophytes are well developed, branched and provided with a root cap. The shoot system is well organised. The stem is generally aerial, branched, straight, thick and hard. Leaves are thin, broad in middle, dark green and of variable shape and measurement.^{[ citation needed ]}

For example, in hot weather they may overheat and suffer from temperature stress. They have no specific adaptations to overcome this, but, if there is enough water in the soil to allow this, they can increase their rate of transpiration by opening their stomata, thus meaning some heat is removed by the evaporating water. However these plants can only tolerate saturated soil for a certain amount of time without a warm temperature. In dry weather they may suffer from water stress (losing more water via transpiration than can be gained from the soil). Again they have no specific adaptations to overcome this, and can only respond by closing their stomata to prevent further transpiration. This does actually have some benefits as it reduces the surface area of the leaves exposed to the atmosphere, which reduces transpiration. Prolonged periods of dehydration, however, can lead to permanent wilting, cell plasmolysis, and subsequent death. Since mesophytes prefer moist, well drained soils, most crops are mesophytes. Some examples are corn (maize), cucurbits, privet, lilac, goldenrod, clover, and oxeye daisy.^{[ citation needed ]}

Related Research Articles

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 cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1,750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. They are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north, with the exception of Rhipsalis baccifera, which is also found in Africa and Sri Lanka. Cacti are adapted to live in very dry environments, including the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis.

Vascular plants, also called tracheophytes or collectively tracheophyta, form a large group of land plants that have lignified tissues for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms, and angiosperms. Scientific names for the group include Tracheophyta, Tracheobionta and Equisetopsida sensu lato. Some early land plants had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones.

Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface into the atmosphere. It covers both water evaporation and transpiration. Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in agricultural irrigation and water resource management.

In botany, a stoma, also called a stomate, is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spaces of the leaf and the atmosphere. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that regulate the size of the stomatal opening.

Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses, and a number of fungi, which are not plants but were previously categorized as such and studied as part of botany.

Plant nutrition is the study of the chemical elements and compounds necessary for plant growth and reproduction, plant metabolism and their external supply. In its absence the plant is unable to complete a normal life cycle, or that the element is part of some essential plant constituent or metabolite. This is in accordance with Justus von Liebig's law of the minimum. The total essential plant nutrients include seventeen different elements: carbon, oxygen and hydrogen which are absorbed from the air, whereas other nutrients including nitrogen are typically obtained from the soil.

Leucanthemum vulgare, commonly known as the ox-eye daisy, oxeye daisy, dog daisy, marguerite and other common names, is a widespread flowering plant native to Europe and the temperate regions of Asia, and an introduced plant to North America, Australia and New Zealand.

Epidendroideae is a subfamily of plants in the orchid family, Orchidaceae. Epidendroideae is larger than all the other orchid subfamilies together, comprising more than 15,000 species in 576 genera. Most epidendroid orchids are tropical epiphytes, typically with pseudobulbs. There are, however, some terrestrials such as Epipactis and even a few myco-heterotrophs, which are parasitic upon mycorrhizal fungi.

Soil moisture is the water content of the soil. It can be expressed in terms of volume or weight. Soil moisture measurement can be based on in situ probes or remote sensing methods.

Ecohydrology is an interdisciplinary scientific field studying the interactions between water and ecological systems. It is considered a sub discipline of hydrology, with an ecological focus. These interactions may take place within water bodies, such as rivers and lakes, or on land, in forests, deserts, and other terrestrial ecosystems. Areas of research in ecohydrology include transpiration and plant water use, adaption of organisms to their water environment, influence of vegetation and benthic plants on stream flow and function, and feedbacks between ecological processes, the soil carbon sponge and the hydrological cycle.

Moisture stress is a form of abiotic stress that occurs when the moisture of plant tissues is reduced to suboptimal levels. Water stress occurs in response to atmospheric and soil water availability when the transpiration rate exceeds the rate of water uptake by the roots and cells lose turgor pressure. Moisture stress is described by two main metrics, water potential and water content.

In plants, the transpiration stream is the uninterrupted stream of water and solutes which is taken up by the roots and transported via the xylem to the leaves where it evaporates into the air/apoplast-interface of the substomatal cavity. It is driven by capillary action and in some plants by root pressure. The main driving factor is the difference in water potential between the soil and the substomatal cavity caused by transpiration.

Ecophysiology, environmental physiology or physiological ecology is a biological discipline that studies the response of an organism's physiology to environmental conditions. It is closely related to comparative physiology and evolutionary physiology. Ernst Haeckel's coinage bionomy is sometimes employed as a synonym.

Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes to keep the body fluids from becoming too diluted or concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution, the more water tends to move into it. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water.

A xerophyte is a species of plant that has adaptations to survive in an environment with little liquid water. Examples of xerophytes include cacti, pineapple and some gymnosperm plants. The morphology and physiology of xerophytes are adapted to conserve water during dry periods. Some species called resurrection plants can survive long periods of extreme dryness or desiccation of their tissues, during which their metabolic activity may effectively shut down. Plants with such morphological and physiological adaptations are said to be xeromorphic. Xerophytes such as cacti are capable of withstanding extended periods of dry conditions as they have deep-spreading roots and capacity to store water. Their waxy, thorny leaves prevent loss of moisture.

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, changes osmotic pressure of cells, and enables mass flow of mineral nutrients. When water uptake by the roots is less than the water lost to the atmosphere by evaporation plants close small pores called stomata to decrease water loss, which slows down nutrient uptake and decreases CO₂ absorption from the atmosphere limiting metabolic processes, photosynthesis, and growth.

Irrigation in viticulture is the process of applying extra water in the cultivation of grapevines. It is considered both controversial and essential to wine production. In the physiology of the grapevine, the amount of available water affects photosynthesis and hence growth, as well as the development of grape berries. While climate and humidity play important roles, a typical grape vine needs 25-35 inches of water a year, occurring during the spring and summer months of the growing season, to avoid stress. A vine that does not receive the necessary amount of water will have its growth altered in a number of ways; some effects of water stress are considered desirable by wine grape growers.

Breeding for drought resistance is the process of breeding plants with the goal of reducing the impact of dehydration on plant growth.

Transpirational cooling is the cooling provided as plants transpire water. Excess heat generated from solar radiation is damaging to plant cells and thermal injury occurs during drought or when there is rapid transpiration which produces wilting. Green vegetation contributes to moderating climate by being cooler than adjacent bare earth or constructed areas. As plant leaves transpire they use energy to evaporate water aggregating up to a huge volume globally every day.

References

↑ Lawrence E., ed. (1999). Henderson's Dictionary of biological terms. London: Longman Group Ltd. ISBN 0-582-22708-9.
↑ Međedović S., Maslić E., Hadžiselimović R. (2002). Biologija 2. Svjetlost, Sarajevo. ISBN 9958-10-222-6.{{cite book}}: CS1 maint: multiple names: authors list (link)

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[Lawrence-1] Lawrence E., ed. (1999). Henderson's Dictionary of biological terms. London: Longman Group Ltd. ISBN 0-582-22708-9.

[Međedović-2] Međedović S., Maslić E., Hadžiselimović R. (2002). Biologija 2. Svjetlost, Sarajevo. ISBN 9958-10-222-6.{{cite book}}: CS1 maint: multiple names: authors list (link)

[1]

[2]