Meristem
/ˈmɛr.əˌstɛm/
Definition
Meristem is plant tissue made of undifferentiated cells that keep dividing to produce new cells. It is the source of primary growth at shoot and root tips and, in some plants, secondary growth in lateral meristems such as the vascular cambium. Unlike mature tissues, meristem cells remain small, densely packed, and capable of developing into specialized structures like leaves, stems, roots, or conducting tissue.
Function in Plants
- Sites of lengthening growth: At shoot tips and root tips, meristem drives primary growth, which lengthens stems and roots and helps the plant explore light, water, and nutrients.
- Source of thickening tissues: In many plants, lateral meristem produces secondary growth, adding wood and bark-like tissues that increase stem and root diameter.
- Control of branching and flowering: Activity in shoot meristem shapes leaf arrangement, branch formation, and the transition from vegetative growth to flower production.
- Value in propagation and recovery: Because meristem contains actively dividing cells, it is used in tissue culture and can help produce clean plant material from valuable or infected stock.
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