What is the meaning of drought in plants?
Drought is generally defined as “a deficiency of precipitation over an extended period of time (usually a season or more), resulting in a water shortage. Droughts typically take months to form and last for months to years, with geographic extents spanning from just a few to thousands of square miles. When an area experiences drought for an extended period of time, it has enormous impacts.Traditionally, a drought is simply water scarcity, normally from a lack of rain. This is essentially the definition that we’ve inherited from 10,000 years of rain-fed agriculture. In a more nuanced form, it has also come to refer to water competition — too many straws in the drink.Drought is a prolonged dry period in the natural climate cycle that can occur anywhere in the world. It is a slow-onset disaster characterized by the lack of precipitation, resulting in a water shortage. Drought can have a serious impact on health, agriculture, economies, energy and the environment.
What causes drought?
When rainfall is less than normal for a period of weeks to years, streamflows decline, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought. Meteorological Drought is based on the degree of dryness or rainfall deficit and the length of the dry period. Hydrological Drought is based on the impact of rainfall deficits on the water supply such as stream flow, reservoir and lake levels, and ground water table decline.The environmental consequences of drought include losses in plant growth; increases in fire and insect outbreaks; altered rates of carbon, nutrient, and water cycling; and local species extinctions. Drought can impact natural ecosystems and the services they provide to human communities.Severity, duration and intensity are three crucial components for drought characteristics ( Figure 2). A drought event can be defined as when the index is smaller than -1. Table 2.Droughts are caused by low precipitation over an extended period of time. Atmospheric conditions such as climate change, ocean temperatures, changes in the jet stream, and changes in the local landscape are all factors that contribute to drought.Soaking rains are the best medicine to alleviate drought. Water that enters the soil recharges groundwater, which in turn sustains vegetation and feeds streams during periods when it is not raining.
How does drought affect plant growth?
Increases in the rate of leaves senescence and drooping, scorching and limp leaves, leaf rolling and brittleness, closed flowers and flower sagging, etiolation, wilting, turgidity, premature fall, senescence and yellowing of leaves are among the most ubiquitous symptoms of drought stress in plants [65,66]. Drought can lead to decreased water quantity and quality, increased incidence of illness or disease, increased mortality rates, and adverse mental health outcomes as livelihoods are challenged. During drought conditions, fuels for wildfire, such as grasses and trees, can dry out and become more flammable.Drought can develop quickly and last only for a matter of weeks, exacerbated by extreme heat and/or wind, but more commonly drought can persist for months or years.Food and Nutrition. Drought can limit the growing season and create conditions that encourage insect and disease infestation in certain crops. Low crop yields can result in rising food prices and shortages, potentially leading to malnutrition. Drought can also affect the health of livestock raised for food.Characteristics of Drought Each drought is unique, but common features of the most severe droughts that have far-reaching human and ecological impacts include long duration, large moisture deficits, and large areal extent, particularly when these impacts occur during a climatological wet season.
What are the three types of effects of drought?
The many different drought impacts are often grouped as “economic,” “environmental,” and “social” impacts. All of these impacts must be considered in planning for and responding to drought conditions. Droughts can alter the ecological balance of aquatic and terrestrial ecosystems, as well as the services that these ecosystems provide to human communities, and limit ecosystems to sequester carbon, hence worsening climate change.Drought is the absence of precipitation, rather than the presence of an event such as a hurricane, tornado, or fire. It’s often described as a “creeping phenomenon” because it slowly impacts many sectors of the economy and operates on many different timescales.Drought is an extended period of unusually dry weather when there is not enough rain.
What are the first signs of a drought?
The first evidence of drought is usually seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease. The effects of a drought on flow in streams and reservoirs may not be noticed for several weeks or months. Drought monitoring involves observing indicators and indices that evaluate changes in a region’s hydrological cycle. Indicators, which are used to describe drought conditions, are variables such as precipitation, temperature, streamflow, ground and reservoir water levels, soil moisture, and snowpack.Generally, drought stress occurs when the available soil-water becomes scanty and atmospheric conditions cause continuous loss of water by transpiration or evaporation. Water deficit is one of the major abiotic stresses, which adversely affects crop growth and yield.plant drought resistance involves four major mechanisms: drought avoidance (da) (or “shoot dehydration avoidance” in some literature), drought tolerance (dt), drought escape (de), and drought recovery [15, 21–26].Characteristics of Drought Each drought is unique, but common features of the most severe droughts that have far-reaching human and ecological impacts include long duration, large moisture deficits, and large areal extent, particularly when these impacts occur during a climatological wet season.Droughts are caused by low precipitation over an extended period of time. Atmospheric conditions such as climate change, ocean temperatures, changes in the jet stream, and changes in the local landscape are all factors that contribute to drought.
What are the symptoms of drought stress in plants?
Under drought conditions, plants may exhibit less common symptoms, such as twig cracks, stunted growth, branch dieback, necrosis, bark cracks, shrub canopies, and tree thinning (Toscano et al. Under certain circumstances, plants might perish due to severe drought-induced stress. Plants under water stress can have many symptoms including yellowing, wilting leaves that develop early fall color and burning or scorching on edges of leaves. Plants may drop some or all of their leaves and appear dead.
What is called a drought?
Overview. Drought is a prolonged dry period in the natural climate cycle that can occur anywhere in the world. It is a slow-onset disaster characterized by the lack of precipitation, resulting in a water shortage. Drought can have a serious impact on health, agriculture, economies, energy and the environment. HORMONAL REGULATION OF TRANSPIRATION. When plants are drought stressed, the plant hormone ABA accumulates in the shoot, where it both inhibits stomatal opening and promotes stomatal closure, resulting in reduced water loss from the plant.At night, stomata close, enabling the plant to save water when photosynthesis is no longer empowered with sunlight. However, depending on the species, or even the variety, residual nighttime transpiration may result in inefficient water loss.Drought stress also alters plant physiological traits such as stomatal functioning, photosynthesis, gaseous exchange, antioxidant system, transpiration rate all of which leads to growth retardation (Raza et al.The primary stress-responsive hormone generated upon drought signal detection is abscisic acid (ABA). It is primarily synthesized in the root and then transported to the leaves to regulate stomatal opening, channel activity, and the expression pattern of ABA-responsive genes (Wani et al.