Tigridia pavonia - wilted overnight - 2018-07-25 focus stack

Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the

turgor pressure Turgor pressure is the force within the cell that pushes the plasma membrane against the cell wall. It is also called ''hydrostatic pressure'', and is defined as the pressure in a fluid measured at a certain point within itself when at equilibri ...

in non-

lignified Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...

plant cell Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capabi ...

s falls towards zero, as a result of diminished water in the

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

. Wilting also serves to reduce water loss, as it makes the leaves expose less surface area. The rate of loss of water from the plant is greater than the absorption of water in the plant. The process of wilting modifies the

leaf angle distribution The Leaf angle distribution (or LAD) of a plant canopy refers to the mathematical description of the angular orientation of the leaves in the vegetation. Specifically, if each leaf is conceptually represented by a small flat plate, its orientation ...

of the plant (or canopy) towards more erectophile conditions. Lower water availability may result from: * drought conditions, where the

soil moisture 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 (e.g., capacitance probes, neutron probes) or remote sensing methods. Water that enters ...

drops below conditions most favorable for plant functioning; * the temperature falls to the point where the plant's vascular system cannot function; * high

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

, which causes water to diffuse from the plant cells and induce shrinkage; * saturated soil conditions, where roots are unable to obtain sufficient oxygen for cellular respiration, and so are unable to transport water into the plant; or * bacteria or fungi that clog the plant's vascular system. Wilting diminishes the plant's ability to transpire and grow. Permanent wilting leads to plant death. Symptoms of wilting and blights resemble one another. The plants may recover during the night when evaporation is reduced as the stomata closes. In woody plants, reduced water availability leads to

cavitation Cavitation is a phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, cal ...

of the xylem. Wilting occurs in plants such as balsam and Ocimum tenuiflorum, holy basil. Wilting is an effect of the plant growth-inhibiting hormone, abscisic acid. With Cucurbitaceae, cucurbits, wilting can be caused by the squash vine borer.

References

Plant physiology Plant pathogens and diseases {{botany-stub