cyanobacterium

Cycadaceae cycas family Stangeriaceae stangeria family Zamiaceae zamia family Cycads are an ancient group of seed plants characterized by a large crown of compound leaves and a stout trunk. They are evergreen, gymnospermous, dioecious plants having large pinnately compound leaves. They are frequently confused with and mistaken for palms or ferns, but are unrelated to either, belonging to the division Cycadophyta. Cycad - Introduction & overview. Cycads are found across much of ...

Including:

• Cycad - Introduction & overview
• Cycad - Taxonomy
• Cycad - Order Cycadales
• Cycad - History
• Cycad - Conservation
• Cycad - Horticulture

Read more here: » Cycad: Encyclopedia - Cycad

Cycads are found across much of the subtropical and tropical parts of the world. They are found in South and Central America (where the greatest diversity occurs), Australia, the Pacific Islands, Japan, China, India, Madagascar, and southern and tropical Africa, where at least 65 species occur. Some are renowned for survival in harsh semi-desert climates, and can grow in sand or even on rock. They are able to grow in full sun or shade, and some are salt tolerant. Though they are a minor component of the plant kingdom today, during the Jurassic period they w ...

See also:

Cycad, Cycad - Introduction & overview, Cycad - Taxonomy, Cycad - Order Cycadales, Cycad - History, Cycad - Conservation, Cycad - Horticulture

Read more here: » Cycad: Encyclopedia II - Cycad - Introduction & overview

Lichens live on various surfaces, such as soil, wood, and rock. They are often the first to settle in places lacking soil, constituting the sole vegetation in some extreme environments such as those found at high mountain elevations and at high latitudes. Some survive in the tough conditions of deserts, and others on frozen soil of the arctic regions. Recent NASA research shows that lichens can even endure extended exposure to space. Some lichens have the aspect of leaves (foliose lichens); others cover the substratum like a crust (crustose lichens); others adopt shrubby forms (fruticose lichens); and the ...

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Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Growth Form

Read more here: » Lichen: Encyclopedia II - Lichen - Morphology and structure

Azolla can reproduce asexualy by breaking off. Each branch that breaks off forms a new plant. Azolla can also reproduce sexually. Like all ferns, Azolla produce spores. Unlike most ferns, Azolla produces two kinds of spores. During the summer months, numerous spherical structures called sporocarps form on the undersides of the branches. The male sporocarp is greenish or reddish and looks like the egg mass of an insect or spider. It is two millimeters in diameter, and inside are numerous male sporangia. Male spores (microspores) are ex ...

See also:

Mosquito fern, Mosquito fern - reproduction, Mosquito fern - Sources

Read more here: » Mosquito fern: Encyclopedia II - Mosquito fern - reproduction

Chemically, phytochrome consists of a chromophore, a single molecule with an open chain of four pyrrole rings, bonded to a protein. It is the chromophore that absorbs light, and as a result changes conformation, thereby also affecting the conformation of the attached protein, changing it from one isoform to the other. The phytochrome chromophore is usually called phytochromobilin, and is closely related to phycobilin (the chromophore of the phycobiliproteins used by cyanobacteria and red algae to capture light for photos ...

See also:

Phytochrome, Phytochrome - Isoforms, Phytochrome - Biochemistry, Phytochrome - Discovery, Phytochrome - Genetic engineering

Read more here: » Phytochrome: Encyclopedia II - Phytochrome - Biochemistry

In plant photosynthesis, incoming light is absorbed by chlorophyll and other accessory pigments in the antenna complexes of photosystem I and photosystem II. The antenna pigments are predominantly chlorophyll α, chlorophyll b and carotenoids; their absorption spectrums are non-overlapping, to broaden the range of light that can be absorbed for photosynthesis. The carotenoids have another role as an antioxidant, t ...

See also:

Chlorophyll, Chlorophyll - Chlorophyll and photosynthesis, Chlorophyll - Chemical structure, Chlorophyll - Evidence for chlorophyll

Read more here: » Chlorophyll: Encyclopedia II - Chlorophyll - Chlorophyll and photosynthesis

Lichens live on various surfaces: soil, trees, rocks, and walls. They are often the first to settle in places lacking soil, constituting the sole vegetation in some extreme environments such as found at high mountain elevations and at high latitudes. Some survive in the tough conditions of deserts, and others on frozen soil of the arctic regions. Recent NASA research shows that lichen can even endure extended exposure to space. Some lichens have the aspect of leaves (foliose lichens); others cover the substratum like a crust (crustose lichens); others adopt shrubby forms (fruticose lichens); and the ...

See also:

Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Classification

Read more here: » Lichen: Encyclopedia II - Lichen - Morphology and structure

There are two isoforms of phytochrome - Pr and Pfr. The Pr isoform absorbs red light (at 660nm) while the Pfr isoform absorbs far-red light (at 730nm). Absorption of light causes phytochrome to inter-convert. Hence, red light makes Pfr, far-red light makes Pr. Phytochrome is made by the plant in the Pr form. Since daylight contains a lot of red light, during the day phytochrome is mostly converted to the Pfr form. At night, phytochrome will slowly convert back to the Pr form. Treatment with far-red light will also convert Pfr back to ...

See also:

Phytochrome, Phytochrome - Isoforms, Phytochrome - Biochemistry, Phytochrome - Discovery, Phytochrome - Genetic engineering

Read more here: » Phytochrome: Encyclopedia II - Phytochrome - Isoforms

Modern knowledge about Cycads began in the 9th century with the discovery by two Arab naturalists that the genus Cycas was used as a source of flour in India. Later, in the 16th century, Antonio Pigafetta, Fernao Lopez de Castanheda and Francis Drake found Cycas plants in the Moluccas, where the seeds were eaten. The first report of cycads in the New World was by Giovanni Lerio in his 1576 trip to Brazil, where he observed a plant named ayrius by the indigenous people; this species is now clas ...

See also:

Cycad, Cycad - Introduction & overview, Cycad - Taxonomy, Cycad - Order Cycadales, Cycad - History, Cycad - Conservation, Cycad - Horticulture

Read more here: » Cycad: Encyclopedia II - Cycad - History

In recent years, many cycads have been dwindling in numbers and may face risk of extinction because of theft and unscrupulous collection from their natural habitats, as well as from habitat destruction. All cycads are in the CITES appendix appearing under the heading Plant Kingdom and under three family names: Cycadaceae, Stangeriaceae and Zamiaceae. All cycads are CITES APPENDIX II except the following, in APPENDIX I: Cycas beddomei Stangeria eriopus All Ceratozamia All Chigua All Encephalartos ...

See also:

Cycad, Cycad - Introduction & overview, Cycad - Taxonomy, Cycad - Order Cycadales, Cycad - History, Cycad - Conservation, Cycad - Horticulture

Read more here: » Cycad: Encyclopedia II - Cycad - Conservation

The phytochrome pigment was discovered by Sterling Hendricks and Harry Borthwick at the USDA-ARS in Beltsville, MD, during a period from the late 1940s to the early 1960s. Using a spectrograph built from borrowed and war-surplus parts, they discovered that red light was very effective for promoting germination or triggering flowering responses. The red light responses were reversible by far-red light, indicating t ...

See also:

Phytochrome, Phytochrome - Isoforms, Phytochrome - Biochemistry, Phytochrome - Discovery, Phytochrome - Genetic engineering

Read more here: » Phytochrome: Encyclopedia II - Phytochrome - Discovery

Because lichens are morphologically small relative to most terrestrial plants, yet require access to sunlight in order to grow, most forms are attached to either large boulders, other inert surfaces, or woody plants in somewhat to completely open or exposed situations. However, where adequate moisture exists, lichens develop on surfaces (particularly those of slow-growing trees) in forests as part of an epiphyte community. Stability (that is, longevity) of a surface is a commonality of most lichen habitats. Lichens are relatively slow-growin ...

See also:

Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Growth Form

Read more here: » Lichen: Encyclopedia II - Lichen - Ecology

Lichens most frequently reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells. Soredia (sing. soredium) are small groups of algal cells surrounded by fungal filaments that form in cavities called soralia, which open when the lichen dries or surrounding tissues die and release the soredia to be dispersed by wind. Another form of diaspore are isidia, elongated outgrowths from the thallus that break off for dispersal. Fruticose lichens in particular can easily fragm ...

See also:

Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Classification

Read more here: » Lichen: Encyclopedia II - Lichen - Reproduction

Lichens most frequently reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells. Soredia (sing. soredium) are small groups of algal cells surrounded by fungal filaments that form in cavities called soralia, which open when the lichen dries or surrounding tissues die and release the soredia to be dispersed by wind. Another form of diaspore are isidia, elongated outgrowths from the thallus that break off for dispersal. Fruticose lichens in particular can easily fragm ...

See also:

Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Growth Form

Read more here: » Lichen: Encyclopedia II - Lichen - Reproduction

Because lichens are morphologically small relative to most terrestrial plants, yet require access to sunlight in order to grow, most forms are attached to either large boulders, other inert surfaces, or woody plants in somewhat to completely open or exposed situations. However, where adequate moisture exists, lichens develop on surfaces (particularly those of slow-growing trees) in forests as part of an epiphyte community. Stability (that is, longevity) of a surface is a commonality of most lichen habitats. Lichens are relatively slow-growin ...

See also:

Lichen, Lichen - Morphology and structure, Lichen - Reproduction, Lichen - Ecology, Lichen - Classification

Read more here: » Lichen: Encyclopedia II - Lichen - Ecology