Hornwort
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Typical Hornworts are found in many tropical areas, and mostly in these tropical areas the plant is diverse. To contrast, in places such as Europe, there are few of these species. They appear in Switzerland, hornworts tend to be annual in Northern Switzerland including other Central European areas as a result of climate changes.[http://www.bryolich.ch/english/bryology/Hornmoose_engl.html] In the US hornworts are located in a number of states, all including: (AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, TN, TX, VA, VT, WA, WI, WV), CAN (AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, YT), DEN (GL), FRA (SPM) | Typical Hornworts are found in many tropical areas, and mostly in these tropical areas the plant is diverse. To contrast, in places such as Europe, there are few of these species. They appear in Switzerland, hornworts tend to be annual in Northern Switzerland including other Central European areas as a result of climate changes.[http://www.bryolich.ch/english/bryology/Hornmoose_engl.html] In the US hornworts are located in a number of states, all including: (AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, TN, TX, VA, VT, WA, WI, WV), CAN (AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, YT), DEN (GL), FRA (SPM) | ||
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Revision as of 03:42, 24 April 2009
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- This page is about the nonvascular plant. For the aquatic plants known as hornwort: see Ceratophyllum
| Hornwort |
|---|
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| Scientific Classification |
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| Genera |
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Family Anthocerotaceae
Family Dendrocerotaceae Family Notothyladaceae |
| bryophyte (plant) |
Contents |
Introduction
Hornworts have a close distinction to another bryophyte plant called a Liverwort. There are 100 known species of hornworts and liverworts.Hornworts are similar to mosses, which people are much more fond of verses liverwort or hornworts.[1] The hornwort is a non-vascular plant. In this order there are three different familes and four different species, that set this plant in to categories. This plant can reproduce sexually and asexually, it is distinguished by the thallus, of the hornwort.
Anatomy
In the distinction to other bryophyte plants, the thallus plays a huge role on its difference to liverworts or mosses. The thallus has a smooth texture to it, also. Therefore the thallus' rhizoids are described as plain and simple, which discludes ventral scales. The rhizoids are what attaches this plant to the ground.The sporophyte is seen as long and narrow, and has a central columella. The central columella is made up of sterile tissue as well as basal meristem. In some anthoceros, the hornwort presents pores in the capsule walls or lacks them. In dendroceros, the thallus is strap shaped, the midbrid is strongly noticeable and quite defined. In megaceros, there are usually more than one chloroplast in just one epidermal cell. It grows to about 1-3 cm wide, as a dark-green hue. This plant is perennial, and tends to grow in clusters; you could say this a social-plantae. Archegonia are found and embedded in the surface of the dorsal, this is behind the apices. The compact ground tissue is measured as 5-8 layers deep. Close to the thallus, is the pores that arise, are similarly distiguished to the stomata. Behind this, the aperature sometimes becomes more round. Hornwort sporophytes tend to be about 3-7cm tall and rage from 0.7-9cm. The valves, in dry air twist spirally and twistingly. The pseudoelaters, is often unbranched or has somewhat branched filaments.[2]In the hornwort the thalloid holds one cell each with a single chloroplast. Therefore, the bottom and basal growth of the sporophyte is needle-like. Leaving the capsule and stomata are columnar.[3]
Reproduction
Sexually
Hornworts can reproduce in two ways, either Asexually or Sexually. The hornwort plant, is very distinctive and similar to many other bryophyte plants in the way they reproduce. In a few types of species the female and male may either grow on just one single plant, however, the female and male organ may be seperated on to two different plants. The Archegonia which is the female organ, and Antheridia which is the male organ are encapsulated a little bit or completely located at the center region on the upper portion of the thallus. During the growth of the Antheridia; the Archegonia tends to break down from a result of water. Many multiple sperms become chemically attracted to the female eggs, these eggs are located at the bottom. The female eggs are chemically attracted to the the base of the archegonia. These then make their way through to become fertalized eggs, thru water. A fertalized egg is also called a [gamete]. And so, the zygotes are spread through out the plant, they can than grow into the next generation. Sporophytes are horn-shaped, and grow from the bottom of sheath under the surface of the gametophyte [thallus]. These hornworts [germinate] exactly from the spores.[4]
Asexually
Hornwort reproduction that is asexual, is engendered, by itself, by broken down thallus.[5]
Gametophyte
During the reproduction of a Hornwort, there is a flat greensheet called the [gametophyte] or [thallus]. The gametophyte in hornworts seen as wrinkled and green as well as spiral-like. The color varies from dark green, light green, and even green-yellow. A hornwort [gametophyte] is usually portrayed as lobed or even sometimes wrinkled, this has a greenish colored sheet this is the [thallus]. The gametophye; depending upon the type of genus can grow spiral-like. The thallus' color is either dark green, light green, to even yellowish in Notothylas. The thallus can be many cells thick. In the genus, Dendroceros the thallus is strap-like each tend to have a thick and central [midrib] with delicate lateral wings. The lateral wings are wavy and ruffle-like. Also, the thallus is connected to hook structures, the smooth rhizoids.Rhizoids bloom at the underside of the thallus.[6]
Sporophyte
Hornwort plants contrast in shape of the sporophyte generation.The hornworts generate spores inside of a greenish, horn-like stalk, instead. Hornwort cells launch as single as well as large chloroplast in every single cell. The color breaks down and is lucid, to the thallus of the plant.[7] With only one thallus many sporophytes can and may be produced. In a hornwort the sporophytes are erect, and needle-like. The length of a hornwort sporophyte run from 10 cm in length. In the genus Notothylas the sporophytes run small, to even 5 mm long, which are initially short and stout. They are even compared to banana-shaped. This structure is a spore capsule nonetheless. Most [sporophytes] apart from the [genus] Notothylas grows consistently clearly above the base. As the sporophytes grow, they are pushed outward. The sporophyte growth the youngest cells are near the base, and move the oldest upward to the top. The more mature cells are the cells on the lower part of the sporophyte. Upon these mature cells The sporophyte relies upon the gametophyte greatly for carbohydrates; without the gametophyte or injury to the gamteophyte the sporophyte could or will suffer. A sporophytes growth splits within its length; beginning at top working its way to the bottom. This happens so that the distribution of the sporophytes can amplify its period. The two halves remain together and joined at the top. The sporophyte even symetrically splits along only one side of the structure to expand the slit on just one side of the capsule. An example of this is shown in the genus' Dendroceros and Megaceros sporophytes. In the genus Notothylas the capsule doesn't split in to, two. The genus Notothylas, sporophytes can split this way , during this process however can decay.[8]
Ecology
Typical Hornworts are found in many tropical areas, and mostly in these tropical areas the plant is diverse. To contrast, in places such as Europe, there are few of these species. They appear in Switzerland, hornworts tend to be annual in Northern Switzerland including other Central European areas as a result of climate changes.[9] In the US hornworts are located in a number of states, all including: (AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, TN, TX, VA, VT, WA, WI, WV), CAN (AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, QC, YT), DEN (GL), FRA (SPM)
Gallery
 Common-name |
 hornwort |
References
- Anthocerotales by the U.S. Department of Agriculture
- Survey of hornwort populations in selected arable fields in the Swiss Plateau Irene Bisang, Luc Lienhard und Ariel Bergamini, unknown publisher, July 2008.
- Reproduction & Dispersal Heino Lepp, Australian National Herbarium, 15 April 2008.
- Sporophytes Heino Lepp, Australian National Herbarium, 15 April 2008.
- Bryophyta Susan Kornfeld, Ari Kornfeld, Date published unknown.
- Hornwort Reproduction Author unknown, ICRA, date unknown.
- What are liverworts and what are hornworts? What are they used for? David Hershey, MadSci Network, April 15.
- Notes on Some Anthocerotae of New Zealand Ella O. Campbell, Tuatara : Journal of the Biological Society, July 1 1981.
See Also
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