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However, internal seed structure is vastly different between these groups. The cotyledon is the embryonic leaf within a seed; monocots have one whereas dicots have two. The evolution of having one or two cotyledons may have arisen 200-150 Mya when monocots and dicots are thought to have diverged.
With the introduction of phyletic thinking in taxonomy (from the system of Eichler 1875–1878 onwards) the predominant theory of monocot origins was the ranalean (ranalian) theory, particularly in the work of Bessey (1915), [2] which traced the origin of all flowering plants to a Ranalean type, and reversed the sequence making dicots the more ...
D. Plumule: the plumule is the shoot of the seed where the leaves will first appear. E. Radicle: the radicle is the root of the seed. In the monocot seed there are also five major parts. A. Seed coat: the seed coat protects the seed. B. Cotyledon: the cotyledon is the leaf of the seed; there is only one cotyledon in monocot seeds. D.
The Cronquist system's definition, for example, is the broadest of all. [14] Rolf Dahlgren and colleagues were responsible for one of the most radical reorganisation of families, and in their 1985 monocot monograph defined the two orders (Asparagales and Liliales) which contain the bulk of monocot geophytes, as constituting the lilioid monocots.
A true root system consists of a primary root and secondary roots (or lateral roots). the diffuse root system: the primary root is not dominant; the whole root system is fibrous and branches in all directions. Most common in monocots. The main function of the fibrous root is to anchor the plant.
Once brace roots emerge from stem nodes, the influence of external factors such as the availability of water, nutrients, light and humidity become prominent. Therefore, a combination of internal and external factors determine the overall organization, shape, and size of individual roots (root system architecture) and, as a result, root function.
basal: attached close to the base (of a plant or an evolutionary tree diagram) climber: a vine that leans on, twines around or clings to other plants for vertical support; glandular hair: a hair tipped with a secretory structure; herbaceous: not woody; usually green and soft in texture; perennial: not an annual or biennial
Coleoptile is the pointed protective sheath covering the emerging shoot in monocotyledons such as grasses in which few leaf primordia and shoot apex of monocot embryo remain enclosed. The coleoptile protects the first leaf as well as the growing stem in seedlings and eventually, allows the first leaf to emerge. [1]