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Vascular plants (also known as tracheophytes or higher plants) are those plants that have lignifiedtissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms. Scientific names for the group include Tracheophyta and Tracheobionta, but neither name is very widely used.
Vascular plants are distinguished by two primary characteristics:
- Vascular plants have vascular tissues, which circulate resources through the plant. This feature allows vascular plants to evolve to a larger size than non-vascular plants, which lack these specialized conducting tissues and are therefore restricted to relatively small sizes.
- In vascular plants, the principal generation phase is the sporophyte, which is usuallydiploid with two sets of chromosomes per cell. Only the germ cells and gametophytes are haploid. By contrast, the principal generation phase in non-vascular plants is usually the gametophyte, which ishaploid with one set of chromosomes per cell. In these plants, generally only the spore stalk and capsule are diploid.
One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spore and the ability to release it higher and to broadcast it farther. Such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, and more branching.
Water transport happens in either xylem or phloem: xylem carries water and inorganic solutes upward toward the leaves from the roots, while phloem carries organic solutes throughout the plant. Group of plants having lignified conducting tissue (xylem vessels or tracheids).
A proposed phylogeny of the vascular plants after Kenrick and Crane is as follows, with modification to the Pteridophyta from Smith et al.
This phylogeny is supported by several molecular studies. Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns (Pteridophyta) are not monophyletic.
Nutrients and water from the soil and the organic compounds produced in leaves are distributed to specific areas in the plant through the xylem and phloem. The xylem draws water and nutrients up from the roots to the upper sections of the plant's body, and the phloem conducts other materials, such as the sucrose produced during photosynthesis, which gives the plant energy to keep growing and seeding.
The xylem consists of tracheids, which are dead hard-walled hollow cells arranged to form tiny tubes to function in water transport. A tracheid cell wall usually contains the polymer lignin. The phloem however consists of living cells called sieve-tube members. Between the sieve-tube members are sieve plates, which have pores to allow molecules to pass through. Sieve-tube members lack such organs as nuclei or ribosomes, but cells next to them, the companion cells, function to keep the sieve-tube members alive.
The movement of nutrients, water and sugars is affected by transpiration, conduction and absorption of water.
The most abundant compound in all plants, as in all life, is water which serves an important role in the various processes taking place. Transpiration is the main process a plant can call upon to move compounds within its tissues. The basic minerals and nutrients a plant is composed of remain, generally, within the plant. Water is constantly lost from the plant through its stomata to the atmosphere.
Water is transpired from the plants leaves via stomata, carried there via leaf veins and vascular bundles within the plants cambium layer. The movement of water out of the leaf stomata creates, when the leaves are considered collectively, a transpiration pull. The pull is created through water surface tension within the plant cells. The draw of water upwards is assisted by the movement of water into the roots via osmosis. This process also assists the plant in absorbing nutrients from the soil as soluble salts, a process known as absorption. Surprisingly, the movement of water upwards requires very little or no energy from the plant. Hydrogen bonds exist between watermolecules, causing them to line up; as the molecules at the top of the plant evaporate, each pulls the next one up to replace it, which in turn pulls on the next one in line.
Answers:All green plants such as bryophytes and tracheophytes are photoautotrophs.Moreover algae also get energy through photosynthesis.
Answers:Ok this isnt to bad. Lets first break it down to The plant seedless vascular plants. The first thing that you should think about when we talk about "adaption to land" is the scarcity of what used to be abundant. Water! So H2O retention is critical for survival. Although the embryophytes are seedless vascular we will start with them to bring us up to par.The primitive features (according to some of my old notes), are the cuticle, this is on the epidermis and is very waxy and inhibits H2O loss. The next is the stomates( stomatal chamber) , which will permit gas exchange and CO2 for photosynthesis The sporopollenin will inhibit H20 loss with a spore wax and permit wind dispersion The embryophytes will break into the bryophytes and the tracheophytes. We want to focus on the tracheophytes because this is the seedless vascular plant that You are talking about. Now back in the embryophytes the sporophyte was initially gametophyte dependant which meant that it thrive on that for nutrients. Well in the vascular seedless we have a gametophyte reduction wich is an evolutionary advancement. It tells us that the nutrients it was abtaining from the adventitious root or the sunlight rather then the gametophyte. *The more energy that was gathered elsewhere also allowed the plant to diminish its gametophyte and conserve energy to other energy Hot Spots. An example of a seedless vascular plant is Aglaophyton Seedless vascular plants will have vascular tissue which allow them to transport nutrients throughout the plant (talked about below) Secondary growth which allows more light for obtaining energy. Reproductive strategy advancement(Pollen) Inside you will have you collenchyma (tissue) cells (which is parenchyma dervived) and it surrounds the stem periphery this is mainly for structural support for a sort of photosynthetic advancement another. The sclerenchyma have fibers and schlerid cells. The fibers serve for more support and the schlerids inhibits herbivores from killing them off. The TISSUE of the vascular plant-Xylem and Phloem XYLEM conducts H20 throughout the plant and Xylem you should know conducts the nutrients (sugars) The ROOT decends for anchorage, absorption and storage The STEM acsends elevates the leaves to light energy. The older terrestrial plants couldn't get high up so they focused on the ground cover. Once the upright growth started, it basically took over. and left the poor guys who could only stay low to get most of the nourishments from the ground. Anyways good luck on everything. Bryan