Edema, (also spelled oedema, and named from the analogous disorder in humans and other animals), is a disorder in plants caused by the build-up of water in plant tissues faster than the leaves can transpire. [1] [2] The excess fluid bursts the cell membranes, causing the appearance of growths, particularly on the underside of leaves. [3]
Edema causes the appearance of growths, mainly on the underside of leaves, and can also cause indentations on the top side of leaves. [4] The growths can take a different appearance depending on the plant species, but can often take the form of needle like hairs, blisters, [3] corky growths and white crusty eruptions. [4] Susceptibility to edema varies by plant species but almost any broad-leaved plant can be affected. [5] In severely affected plants the growths can also appear on the stems and cause leaves to turn yellow and drop off, [4] leaves can also become distorted. [5] If the conditions causing edema are prolonged then the plant can become spindly and have stunted growth. [4]
Edema can often be confused with a variety of other plant conditions, such as powdery mildew or other mould, pests, viruses or nutrient crystals. [6] [5]
A number of changes to the growing environment can all contribute to the improvement of edema symptoms. These include:
Minor cases are unlikely to significantly harm the plant. [7] If adequately treated by improving conditions, new growth will not be affected, [5] however the growths that occurred on leaves during the episode of edema will remain present indefinitely.
Severe cases can cause stunted growth, a spindly appearance, [4] and yellow leaves which can eventually fall off of the plant. [5]
The disorder is not infectious and if edema is the only problem, then the plants are safe to handle and the parts of the plant which would usually be edible will remain safe to eat. [8] However, care should be taken to ensure that other problems, such as mould or pests have not been mistaken for edema.[ citation needed ]
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the surface of the soil, but roots can also be aerial or aerating, that is, growing up above the ground or especially above water.
Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions in a solution. In soils, it is measured in a slurry of soil mixed with water, and normally falls between 3 and 10, with 7 being neutral. Acid soils have a pH below 7 and alkaline soils have a pH above 7. Ultra-acidic soils and very strongly alkaline soils are rare.
Physiological plant disorders are caused by non-pathological conditions such as poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, and affect the functioning of the plant system. Physiological disorders are distinguished from plant diseases caused by pathogens, such as a virus or fungus. While the symptoms of physiological disorders may appear disease-like, they can usually be prevented by altering environmental conditions. However, once a plant shows symptoms of a physiological disorder it is likely that, that season's growth or yield will be reduced.
Boron deficiency is a common deficiency of the micronutrient boron in plants. It is the most widespread micronutrient deficiency around the world and causes large losses in crop production and crop quality. Boron deficiency affects vegetative and reproductive growth of plants, resulting in inhibition of cell expansion, death of meristem, and reduced fertility.
Calcium (Ca) deficiency is a plant disorder that can be caused by insufficient level of biologically available calcium in the growing medium, but is more frequently a product of low transpiration of the whole plant or more commonly the affected tissue. Plants are susceptible to such localized calcium deficiencies in low or non-transpiring tissues because calcium is not transported in the phloem. This may be due to water shortages, which slow the transportation of calcium to the plant, poor uptake of calcium through the stem, or too much nitrogen in the soil.
Nitrogen deficiency is a deficiency of nitrogen in plants. This can occur when organic matter with high carbon content, such as sawdust, is added to soil. Soil organisms use any nitrogen available to break down carbon sources, making nitrogen unavailable to plants. This is known as "robbing" the soil of nitrogen. All vegetables apart from nitrogen fixing legumes are prone to this disorder.
Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils, because potassium ions (K+) are highly soluble and will easily leach from soils without colloids. Potassium deficiency is also common in chalky or peaty soils with a low clay content. It is also found on heavy clays with a poor structure.
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.
Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate medium. The word "aeroponic" is derived from the Greek meanings of aer and ponos. Aeroponic culture differs from both conventional hydroponics, aquaponics, and in-vitro growing. Unlike hydroponics, which uses a liquid nutrient solution as a growing medium and essential minerals to sustain plant growth, or aquaponics, which uses water and fish waste, aeroponics is conducted without a growing medium. It is sometimes considered a type of hydroponics, since water is used in aeroponics to transmit nutrients.
Soil acidification is the buildup of hydrogen cations, which reduces the soil pH. Chemically, this happens when a proton donor gets added to the soil. The donor can be an acid, such as nitric acid, sulfuric acid, or carbonic acid. It can also be a compound such as aluminium sulfate, which reacts in the soil to release protons. Acidification also occurs when base cations such as calcium, magnesium, potassium and sodium are leached from the soil.
Carmona is a genus of flowering plants in the borage family, Boraginaceae. Members of the genus are commonly known as scorpionbush.
Cochliobolus miyabeanus is a fungus that causes brown spot disease in rice.
Damping off is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions.
A microsite is a term used in ecology to describe a pocket within an environment with unique features, conditions or characteristics. Classifying different microsites may depend on temperature, humidity, sunlight, nutrient availability, soil physical characteristics, vegetation cover, etc. Being a sub environment within an environment, we will examine the qualities that differentiate a microsite from another within an environment in this piece.
Mycosphaerella coffeicola is a sexually reproducing fungal plant pathogen. It is most commonly referred to as the asexual organism Cercospora coffeicola.
This glossary of viticultural terms list some of terms and definitions involved in growing grapes for use in winemaking.
Centrosema pubescens, common name centro or butterfly pea, is a legume in the family Fabaceae, subfamily Faboideae, and tribe Phaseolae. It is native to Central and South America and cultivated in other tropical areas as a forage for livestock.
Korean natural farming (KNF) takes advantage of indigenous microorganisms (IMO) to produce fertile soils that yield high output without the use of herbicides or pesticides. A result is an improvement in soil health, improving loaminess, tilth and structure, and attracting large numbers of earthworms. KNF also enables odour-free hog and poultry farming without the need to dispose of effluent. This practice has spread to over 30 countries, and is used by individuals and commercial farms.
Seventeen elements or nutrients are essential for plant growth and reproduction. They are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), boron (B), manganese (Mn), copper (Cu), zinc (Zn), molybdenum (Mo), nickel (Ni) and chlorine (Cl). Nutrients required for plants to complete their life cycle are considered essential nutrients. Nutrients that enhance the growth of plants but are not necessary to complete the plant's life cycle are considered non-essential. With the exception of carbon, hydrogen and oxygen, which are supplied by carbon dioxide and water, and nitrogen, provided through nitrogen fixation, the nutrients derive originally from the mineral component of the soil. The Law of the Minimum expresses that when the available form of a nutrient is not in enough proportion in the soil solution, then other nutrients cannot be taken up at an optimum rate by a plant. A particular nutrient ratio of the soil solution is thus mandatory for optimizing plant growth, a value which might differ from nutrient ratios calculated from plant composition.