Meristem in the context of Cellular differentiation

Trunks, also called boles, are the stems of woody plants and the main structural element of trees. The woody part of the trunk consists of dead but structurally significant heartwood and living sapwood, which is used for nutrient storage and transport. Separating the wood from the bark is the cambium, from which trunks grow in diameter. Bark is divided between the living inner bark (the phloem), which transports sugars, and the outer bark, which is a dead protective layer.

The precise cellular makeup of these components differs between non-flowering plants (gymnosperms) and flowering plants (angiosperms). A variety of specialised cells facilitate the storage of carbohydrates, water, minerals, and transport of water, minerals, and hormones around the plant. Growth is achieved by division of these cells. Vertical growth is generated from the apical meristems (stem tips), and horizontal (radial) growth, from the cambium. Growth is controlled by hormones, which send chemical signals for how and when to grow.

In botany, a sport or bud sport, traditionally called lusus, is a part of a plant that shows morphological differences from the rest of the plant. Sports may differ by foliage shape or color, flowers, fruit, or branch structure. The cause is generally thought to be chance genetic mutations in a single cell. Sports may also arise from stable changes in gene expression due to epigenetic modifications, including histone modification, DNA methylation, chromatin remodeling and RNA silencing. If the clonal descendants of a modified cell eventually form a meristem that gives rise to new plant parts, those may be of a new phenotype. Often only part of the meristem cells are affected, resulting in genetic chimerism in such sports.

The vascular cambium is the main growth tissue in the stems and roots of many plants exhibiting secondary growth, specifically in dicots such as buttercups and oak trees, gymnosperms such as pine trees, as well as in certain other vascular plants. It produces secondary xylem inwards, towards the pith, and secondary phloem outwards, towards the bark. Generally, more secondary xylem is produced than secondary phloem.

In herbaceous plants, it occurs in the vascular bundles which are often arranged like beads on a necklace forming an interrupted ring inside the stem. In woody plants, it forms a cylinder of unspecialized meristem cells, as a continuous ring from which the new tissues are grown. Unlike the xylem and phloem, it does not transport water, minerals or food through the plant. Other names for the vascular cambium are the main cambium, wood cambium, or bifacial cambium.

Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born (or hatches from its egg), it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.

According to plant physiologist A. Carl Leopold, the properties of organization seen in a plant are emergent properties which are more than the sum of the individual parts. "The assembly of these tissues and functions into an integrated multicellular organism yields not only the characteristics of the separate parts and processes but also quite a new set of characteristics which would not have been predictable on the basis of examination of the separate parts."

In botany, an inflorescence is a group or cluster of flowers arranged on a plant's stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis (peduncle) and by the timing of its flowering (determinate and indeterminate).

Morphologically, an inflorescence is the modified part of the shoot of seed plants where flowers are formed on the axis of a plant. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes.

A body (Latin: corpus) is the physical material of an organism. It is only used for organisms which are in one part or whole. There are organisms which change from single cells to whole organisms: for example, slime molds. For them the term 'body' would mean the multicellular stage. Other uses:

• Plant body: plants are modular, with modules being created by meristems and the body generally consisting of both the shoot system and the root system, with the body's development being influenced by its environment.
• Cell body: here it may be used for cells like neurons which have long axons (nerve fibres). The cell body is the part with the nucleus in it.

The body of a dead person is also called a corpse or cadaver. The dead bodies of vertebrate animals and insects are sometimes called carcasses.

Primary growth in plants is growth that takes place from the tips of roots or shoots. It leads to lengthening of roots and stems and sets the stage for organ formation. It is distinguished from secondary growth that leads to widening. Plant growth takes place in well defined plant locations. Specifically, the cell division and differentiation needed for growth occurs in specialized structures called meristems. These consist of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells continue to divide until they differentiate and then lose the ability to divide. Thus, the meristems produce all the cells used for plant growth and function.

At the tip of each stem and root, an apical meristem adds cells to their length, resulting in the elongation of both. Examples of primary growth are the rapid lengthening growth of seedlings after they emerge from the soil and the penetration of roots deep into the soil. Furthermore, all plant organs arise ultimately from cell divisions in the apical meristems, followed by cell expansion and differentiation.

A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they undergo meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm. Unlike animals, plants do not have germ cells designated in early development. Instead, germ cells can arise from somatic cells in the adult, such as the floral meristem of flowering plants.

Cauliflower is one of several vegetables cultivated from the species Brassica oleracea in the genus Brassica, which is in the Brassicaceae (or mustard) family. Cauliflower usually grows with one main stem that carries a large, rounded "head" made of tightly clustered, immature white or off-white flower buds called the "curd". Typically, only the "head" is eaten.

An annual plant that reproduces by seed, the cauliflower head is composed of a (generally) white inflorescence meristem. Although cauliflower heads resemble those in broccoli, the latter differs in having flower buds as the edible portion.

Sieve elements or sieve tube elements are specialized cells that are important for the function of phloem, which is a highly organized tissue that transports organic compounds made during photosynthesis. Sieve elements are the major conducting cells in phloem. Conducting cells aid in transport of molecules especially for long-distance signaling. In plant anatomy, there are two main types of sieve elements. Companion cells and sieve cells originate from meristems, which are tissues that actively divide throughout a plant's lifetime. They are similar to the development of xylem, a water conducting tissue in plants whose main function is also transportation in the plant vascular system. Sieve elements' major function includes transporting sugars over long distance through plants by acting as a channel.

Sieve elements elongate cells containing sieve areas on their walls. Pores on sieve areas allow for cytoplasmic connections to neighboring cells, which allows for the movement of photosynthetic material and other organic molecules necessary for tissue function. Structurally, they are elongated and parallel to the organ or tissue that they are located in. Sieve elements typically lack a nucleus and contain none to a very small number of ribosomes. The two types of sieve elements, sieve tube members and sieve cells, have different structures. Sieve tube members are shorter and wider with greater area for nutrient transport while sieve cells tend to be longer and narrower with smaller area for nutrient transport. Although the function of both of these kinds of sieve elements is the same, sieve cells are found in gymnosperms, non-flowering vascular plants, while sieve tube members are found in angiosperms, flowering vascular plants.

Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium. All the vascular tissues within a particular plant together constitute the vascular tissue system of that plant.

The cells in vascular tissue are typically long and slender. Since the xylem and phloem function in the conduction of water, minerals, and nutrients throughout the plant, it is not surprising that their form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the sections of a pipe might be. As the plant grows, new vascular tissue differentiates in the growing tips of the plant. The new tissue is aligned with existing vascular tissue, maintaining its connection throughout the plant. The vascular tissue in plants is arranged in long, discrete strands called vascular bundles. These bundles include both xylem and phloem, as well as supporting and protective cells. In stems and roots, the xylem typically lies closer to the interior of the stem with phloem towards the exterior of the stem. In the stems of some Asterales dicots, there may be phloem located inwardly from the xylem as well.

Bryophyllum (from the Greek βρῦον/βρύειν bryon/bryein = sprout, φύλλον phyllon = leaf) is a group of plant species of the family Crassulaceae native to Madagascar. It is a section or subgenus within the genus Kalanchoe, and was formerly placed at the level of genus. This section is notable for vegetatively growing small plantlets on the fringes of the leaves; these eventually drop off and root. These plantlets arise from mitosis of meristematic-type tissue in notches in the leaves.

Nowadays, bryophyllums are naturalized in many parts of the tropics and subtropics, and deliberately cultivated for their attractiveness or for their interesting reproduction as a vegetative reproductive plant.