DIVISION CONIFEROPHYTA PDF

All conifers, from pine trees to leylandii to yew trees, are within the Division Pinophyta (aka Coniferophyta). The number of species in this. Division Coniferophyta: Conifers. CONIFERALES. The conifers are the most diverse (about 50 genera and species) and familiar of the. They obtain their nutrients via photosynthesis. Division – Coniferophyta ( Pinophyta). Organisms belonging to the Conifer division possess a distinct xylem and.

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The Pinophytaalso known as Coniferophyta or Coniferaeor commonly as conifersare a division of vascular land plants containing a single extant classPinopsida. They are gymnospermscone-bearing seed plants. All extant conifers are perennial woody plants with secondary growth. The great majority are treesthough a few are shrubs.

Examples include cedarsDouglas firscypressesfirsjuniperskaurilarchespineshemlocksredwoodssprucesconifedophyta yews. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere[1] but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The narrow conical shape of northern conifers, and their divisiln limbs, ocniferophyta them shed snow.

Many of them seasonally alter their biochemistry to make them more resistant to freezing. While tropical rainforests have more biodiversity and turnover, the immense conifer forests of the world represent the largest terrestrial carbon sink. Conifers are of great economic value for softwood lumber and paper production. The earliest conifers in the fossil record date to the late Carboniferous Pennsylvanian period about million years coniferophytx[3] possibly arising from Diviwiona genus of seed-bearing Gondwanan plants with cone-like fertile structures.

Plant Divisions: Conifers

Pinophytes, Cycadophytesand Ginkgophytes all developed at this time. Other adaptations are pollen so fertilisation can occur without water and the seed, which allows the embryo to be transported and developed elsewhere. Conifers coniferkphyta to be one of conifero;hyta taxa that benefited from the Permian—Triassic extinction eventand were the dominant land plants of the Mesozoic. They were overtaken by the flowering plants, which first appeared in the Cretaceous, and became dominant in the Cenozoic era.

They were the main food of herbivorous dinosaursand their resins and poisons would have given protection against herbivores. Reproductive features of modern conifers had evolved by the end of the Mesozoic era.

Conifer fivision a Latin word, a compound of conus cone and ferre to bearmeaning “the one that bears a cone s “. A descriptive name in widespread use for the conifers at whatever rank is chosen is Coniferae Art 16 Ex 2. Alternatively, ” descriptive botanical names ” may also be used at any rank above family. This means that if conifers are considered a division, they may be called Pinophyta or Coniferae.

As a class they may be called Pinopsida or Coniferae. As an order they may be called Pinales or Coniferae or Coniferales.

Conifers are the largest and economically divisiln important component group of the gymnosperms, but nevertheless they comprise only one of the four groups. The division Pinophyta consists of just one class, Pinopsida, which includes both living cojiferophyta fossil taxa.

Subdivision of the living conifers into two or more orders has been proposed from time to time. The most commonly seen in the past was a split into two orders, Taxales Taxaceae only and Pinales the restbut recent research into DNA sequences suggests that this interpretation leaves the Pinales without Taxales as paraphyleticand the latter order is no longer considered distinct.

A more accurate subdivision would be to split the class into three orders, Pinales containing only Pinaceae, Araucariales containing Araucariaceae and Podocarpaceae, and Cupressales containing the remaining families including Taxaceaebut there has not been any significant support for such a split, with the majority of opinion preferring retention of all the families within a single order Pinales, despite their divisiln and diverse morphology.

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The conifers are now accepted as comprising seven families, [6] with a total of 65—70 genera and — species accepted names. In other interpretations, the Cephalotaxaceae may be better included within the Taxaceae, and some authors additionally recognize Phyllocladaceae as distinct from Podocarpaceae in which it is included here. The family Taxodiaceae is here included in family Cupressaceae, but was widely recognized in the past and can still be found in many field guides.

Plant Divisions: Conifers | Tentative Plant Scientist

The conifers are an ancient group, with a fossil record extending back about million years to the Paleozoic in the late Carboniferous period; even many of the modern genera are recognizable from fossils 60— million years old.

Other classes and orders, now long extinct, also occur as fossils, particularly from the late Paleozoic and Mesozoic eras. Fossil conifers included many diverse forms, the most dramatically distinct from modern conifers being some herbaceous conifers with no woody stems. Major fossil orders of conifers or conifer-like plants include the CordaitalesVojnovskyalesVoltziales and perhaps also the Czekanowskiales possibly more closely related to the Ginkgophyta. All living conifers are woody plants, and most are trees, the majority having monopodial growth form a single, straight trunk with side branches with strong apical dominance.

Many conifers have distinctly scented resinsecreted to protect the tree against insect infestation and fungal infection of wounds. Fossilized resin hardens into amber. The size of mature conifers varies from less than one meter, to over meters. The tallest is a Coast Redwood Sequoia sempervirenswith a height of The largest tree by three-dimensional volume is a Giant Sequoia Sequoiadendron giganteumwith a volume Since most conifers are evergreens, [1] the leaves of many conifers are long, thin and have a needle-like appearance, but others, including most of the Cupressaceae and some of the Podocarpaceaehave flat, triangular scale-like leaves.

Some, notably Agathis in Araucariaceae and Nageia in Podocarpaceae, have broad, flat strap-shaped leaves. Others such as Araucaria columnaris have leaves that are awl-shaped. In many species with spirally arranged leaves, such as Abies grandis picturedthe leaf bases are twisted to present the leaves in a very flat plane for maximum light capture.

Apache Pine, Pinus engelmannii. The stomata are in lines or patches on the leaves, and can be closed when it is very dry or cold.

The leaves are often dark green in colour, which may help absorb a maximum of energy from weak sunshine at high latitudes or under forest canopy shade.

Conifers from hotter areas with high sunlight levels e. Turkish Pine Pinus brutia often have yellower-green leaves, while others e. In the great majority of genera the leaves are evergreenusually remaining on the plant for several 2—40 years before falling, but five genera LarixPseudolarixGlyptostrobusMetasequoia and Taxodium are deciduous divixion, shedding the leaves in autumn and leafless through the winter. Tree rings are records of the influence of environmental conditions, their anatomical characteristics record growth diviskon changes produced by these changing conditions.

The microscopic structure of conifer wood consists of two types of cells: The tracheids of earlywood formed at the beginning of a growing season have large radial sizes and smaller, thinner conifwrophyta walls.

Then, the first tracheids of the transition zone are formed, where the radial size of cells and diivsion of their cell walls changes considerably. Finally, the latewood tracheids are formed, with small radial sizes and greater cell wall thickness. This is the basic pattern of the internal cel structure of conifer tree rings. Most conifers are monoeciousbut some are subdioecious or dioecious ; all are wind-pollinated.

voniferophyta Conifer seeds develop inside a protective cone called a strobilus. In PinaceaeAraucariaceaeSciadopityaceae and most Cupressaceaethe cones are woodyand when mature the scales usually spread open allowing the seeds to fall out and be dispersed by the wind.

Ripe cones may remain on the plant for a varied amount of time before falling to the ground; in some fire-adapted pines, conferophyta seeds may be stored in closed cones for up to 60—80 years, being released only when a fire kills the parent tree.

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In the families PodocarpaceaeCephalotaxaceaeTaxaceaeand one Cupressaceae genus Juniperusthe scales are soft, fleshy, sweet and brightly colored, and are eaten by fruit-eating birds, which then pass the seeds in their droppings. These fleshy scales are except in Juniperus known as arils. In some of these conifers e. Taxaceaethe cone is reduced to just one seed divisipn or e.

Cephalotaxaceae the several scales of a cone develop into individual arils, giving the appearance of a cluster of berries. The male cones have structures called microsporangia that produce yellowish pollen through meiosis. Pollen is released and carried by the wind to female cones. Pollen grains from living pinophyte species produce pollen tubes, much like those of angiosperms. The gymnosperm male gametophytes pollen grains are carried by wind to a female cone and are drawn into a tiny opening on the ovule called the micropyle.

It is within the ovule that pollen-germination occurs.

From here, a pollen tube seeks out the female gametophyte, which contains archegonia each with an egg, and if successful, fertilization occurs. The resulting zygote develops into an embryowhich along with the female gametophyte nutritional material for the growing embryo and its surrounding integument, becomes a seed.

Eventually the seed may fall to the ground and, if conditions permit, conifeophyta into a new plant. In forestrythe terminology of flowering plants has commonly though inaccurately been applied to cone-bearing trees as well.

The male cone and unfertilized female cone are called male flower and female flowerrespectively. After fertilization, the female cone is termed fruitwhich undergoes ripening maturation. It coniiferophyta found recently that the pollen of conifers transfers the mitochondrial organelles to the embryoa sort of meiotic drive that perhaps explains why Pinus and other conifers are so productive, and perhaps also has bearing on observed?

Conifers are heterosporousgenerating two different types of spores: These spores develop on separate male and female sporophylls on separate male and female cones.

In the male cones, microspores are produced from microsporocytes by meiosis. The microspores develop into pollen grains, which are male gametophytes.

Large amounts of pollen are released and carried by the wind. Some pollen grains will land on a female cone for pollination. The generative cell in the pollen grain divides into two haploid sperm cells by duvision leading to the development of the pollen tube. At fertilization, one of the sperm cells unites its haploid nucleus with the haploid nucleus of an egg cell. The female cone develops two ovule, each of which contains haploid haploid megaspores. A megasporocyte is divided by meiosis in each ovule.

Each winged pollen grain is a four celled male gametophyte Three of the four cells break down leaving diivision a single surviving cell which will develop into coniderophyta female multicellular gametophyte. Divvision female divsiion grow to produce two or more archegoniaeach of which contains an egg. Upon fertilization, the diploid egg will give rise to the embryo, and a seed is produced.

Pinophyta – Wikipedia

The female cone then opens, releasing the seeds which grow to a young seedling. Conifer reproduction is synchronous with seasonal changes in temperate zones. Reproductive development slows to a halt during each winter season, and then resumes each spring. The conkferophyta strobilus development is completed in a single year. Conifers are classified by three reproductive cycles, namely; 1- 2- or The cycles refers to the completion of female strobilus development from initiation to seed maturation.