The meristem is a type of tissue found in plants. It consists 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 a time when they get differentiated and then lose the ability to divide.
Differentiated plant cells generally cannot divide or produce cells of a different type. Meristematic cells are undifferentiated or incompletely differentiated. They are totipotent and capable of continued cell division. Division of meristematic cells provides new cells for expansion and differentiation of tissues and the initiation of new organs, providing the basic structure of the plant body. The cells are small, with small vacuoles or none, and protoplasm filling the cell completely. The plastids (chloroplasts or chromoplasts), are undifferentiated, but are present in rudimentary form (proplastids). Meristematic cells are packed closely together without intercellular spaces. The cell wall is a very thin primary cell wall.
The term meristem was first used in 1858 by Carl Wilhelm von Nägeli (1817–1891) in his book Beiträge zur Wissenschaftlichen Botanik ("Contributions to Scientific Botany"). It is derived from the Greek word merizein (μερίζειν), meaning to divide, in recognition of its inherent function.
There are three types of meristematic tissues: apical (at the tips), intercalary or basal (in the middle), and lateral (at the sides). At the meristem summit, there is a small group of slowly dividing cells, which is commonly called the central zone. Cells of this zone have a stem cell function and are essential for meristem maintenance. The proliferation and growth rates at the meristem summit usually differ considerably from those at the periphery.
Apical meristems are the completely undifferentiated (indeterminate) meristems in a plant. These differentiate into three kinds of primary meristems. The primary meristems in turn produce the two secondary meristem types.
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
The presentation of tree growth and formation of wood anatomical structures, linked to the description of specific physical and mechanical properties, makes it possible to understand the different for
A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral.
The vascular cambium is the main growth tissue in the stems and roots of many plants, 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. 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.
Cork cambium (pl. cambia or cambiums) is a tissue found in many vascular plants as a part of the epidermis. It is one of the many layers of bark, between the cork and primary phloem. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems. It is found in woody and many herbaceous dicots, gymnosperms and some monocots (monocots usually lack secondary growth). It is one of the plant's meristems – the series of tissues consisting of embryonic disk (incompletely differentiated) cells from which the plant grows.
The concomitant occurrence of tissue growth and organization is a hallmark of organismal development(1-3). This often means that proliferating and differentiating cells are found at the same time in a continuously changing tissue environment. How cells ada ...
Despite worldwide reports of high tree mortality, growing evidence indicates that many tree species are well adapted to survive repeated dry spells. The drought resilience of trees is related to their phenotypic plasticity and ecotypic differentiation. Whe ...
The symbiont-bearing jellyfish Cassiopea live a benthic lifestyle, positioning themselves upside-down on sediments in shallow waters to allow their endosymbiotic algae to photosynthesize in the sunlight. Over the last decades Cassiopea has become increasin ...