apical meristem


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apical meristem

a region of dividing tissue at the growing tips of roots and shoots that is responsible for increase in length of the plant body. MERISTEM cells are small, with thin walls and CYTOPLASM containing few vacuoles. They undergo active MITOSIS when growth is occurring (depending on the season) and the new cells look similar to the parental ones but become more vacuolated and elongated. Eventually, further away from the meristem, the cells undergo the process of CELL DIFFERENTIATION, taking on the appearance of mature plant cells.

Meristematic tissues are delicate and in need of protection. In shoots the apices are covered by tiny leaves forming apical buds at the tips of the branches and axillary buds at the nodes where the leaves join the stem. Root structures are less complex, each root-tip meristem being protected by a shield of loose cells called a ROOT CAP. Compare CAMBIUM.

References in periodicals archive ?
Most commonly, dichotomy implies equal division of the shoot apical meristem (Tomlinson, 1990), but the term has also been defined as two independently functioning axes (Gola, 2014) or as two more or less equal axes.
AtTPST is expressed throughout the plant, and the highest expression is in the root apical meristem. A knockout mutant of AtTPST (tpst-1) displayed pale green leaves and early senescence in the aboveground tissues and had an extremely short root phenotype accompanied by a considerable decrease in proximal meristem activity.
thaliana leaves and sepals, FIL and YAB3 genes are upregulated by KAN1 and ARF4, and, in turn, FIL and YAB3 stimulate the expression of ARF4, KAN1, and AS1 [92, 94, 95], and besides, in complex with LUG and SEU promote not only organ polarity, but embryonic shoot apical meristem initiation and maintenance [93].
Day length and light quality play a crucial role in flower induction both in vivo and in vitro possibly due to altered photosynthetic turnover on flowering and are believed to be essentially perceived by expanded leaves; then, "florigen" (sucrose and isopentenyladenine) will be produced and moved directly or indirectly to shoot apical meristem (SAM) to guide flowering determination [39].
To induce shoot regeneration apical meristem of Chrysanthemum were inoculated on MS medium supplemented with BAP alone (Table-1) MS media supplemented with five different concentrations of BAP (0.5, 1.0, 2.0, 3.0 and 4.0 mg/l) were tested for their effect on shoot initiation (Fig.
Pastures deferred at elevated heights in the beginning of the fall usually have a greater number of tillers with a remaining apical meristem and, in such condition, photoassimilates are preferentially reallocated for the development and maintenance of the existing tillers (ROBSON et al., 1988).
Among the analyzed characteristics, the height of the apical meristem, diameter and the dry mass of underground structure, shoot and whole seedling dry mass were statistically higher in P.
Beyond that, of course, is the possibility of the endophyte's presence in the host's apical meristem that will need to be explored.
These blades were located below the first three apical blades that had separated from the apical meristem. Subapical blades were chosen for nests because field observations at two locations from the northern-central coast of Chile indicated that P.
The study present efficient shoot regeneration of fenugreek using apical meristem, and cotyledon leaf explants on different concentrations of TDZ with or without IBA.
To approximate the mechanical effects of browsing, apical stems were clipped at 4.0 mm stem diameter proximal to the apical meristem, which is the average bite diameter of shoots browsed by moose in the study area (Carson et al.
In plants, new cells are produced only in apical meristem and lateral meristem.