Non-vascular plant

Non-vascular plant

Non-vascular plants is a general term for those plants without a vascular system (xylem and phloem). Although non-vascular plants lack these particular tissues, a number of non-vascular plants possess tissues specialized for internal transport of water.

Non-vascular plants do not have a wide variety of specialized tissue. Liverworts have structures that look like leaves, but they are not true leaves because they have no xylem or phloem. Likewise, mosses and algae have no such tissues.

All plants have a life cycle with an alternation of generations between a diploid sporophyte and a haploid gametophyte, but only nonvascular plants can potentially have a dominant gametophyte generation. In these plants, the sporophytes grow from and are dependent on gametophytes for taking in water and other materials.

Non-vascular groups

The term non-vascular plant is no longer used in scientific nomenclature. Non-vascular plants include two distantly related groups:

  • Bryophytes - Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerotophyta (hornworts). In these groups, the primary plants are the haploid gametophytes, with the only diploid portion being the attached sporophyte, consisting of a stalk and sporangium. Because these plants lack water-conducting tissues, they can't become as tall as most vascular plants.
  • Algae - especially the green algae. Recent studies have demonstrated that the algae actually consist of several unrelated groups. It turns out that common features of living in water and photosynthesis were misleading as indicators of close relationship. Only the Archaeplastida are still considered relatives of the plants.

Both of these groups are occasionally termed the "lower plants"; the term "lower" refers to these plants' status as the earliest plants to evolve. However, the term "lower" plants is not precise, since it frequently is used to include some vascular plants, the ferns and fern allies.

In the past, the term non-vascular plant included not only all the algae, but also the fungi as well. Today, it is recognized that these groups are not closely related to plants, and have a very different biology.

See also

External links

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • non-vascular plant — noun Any plant that does not have a vascular system See Also: vascular plant …   Wiktionary

  • Vascular plant — Vascular Plants Temporal range: Mid Silurian [1] Recent Scientific classification Kingdom …   Wikipedia

  • vascular plant — noun Any plant possessing vascular tissue (xylem and phloem), including ferns, conifers, and flowering plants. Syn: tracheophyte Ant: non vascular plant, thallu …   Wiktionary

  • List of the non-vascular plants of Canada — Parent page: Flora of Canada This is a listing of the non vascular plants of Canada, and includes the mosses, liverworts and hornworts. = Bryophyta (mosses) = Andreaeaceae Aulacomniaceae Catoscopiaceae Mniaceae …   Wikipedia

  • Plant — For other uses, see Plant (disambiguation). Plants Temporal range: Early Cambrian to recent, but see text, 520–0 Ma …   Wikipedia

  • Plant defense against herbivory — Poison ivy produces urushiol to protect the plant from herbivores. In humans this chemical produces an allergic skin rash, known as urushiol induced contact dermatitis …   Wikipedia

  • Plant stem — Stem showing internode and nodes plus leaf petioles A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence… …   Wikipedia

  • Plant evolutionary developmental biology — For a more ecological discussion on the evolution of plant morphology, refer to Evolutionary history of plants Evolutionary developmental biology (evo devo) refers to the study of developmental programs and patterns from an evolutionary… …   Wikipedia

  • plant life — noun (botany) a living organism lacking the power of locomotion • Syn: ↑plant, ↑flora • Derivationally related forms: ↑floral (for: ↑flora), ↑plantal ( …   Useful english dictionary

  • Plant sexuality — Close up of an Echinopsis spachiana flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a perfect flower. Plant sexuality covers the wide variety of sexual reproduction systems found across the plant… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”