plantestruktur

Plantestruktur describes how a plant is built and organized, from cells to tissues to organs. The architecture typically includes three tissue systems: dermal, ground, and vascular. Plants have two main structural systems: a root system that anchors and absorbs, and a shoot system that supports stems and leaves, and, in flowering plants, flowers and fruits.

Cells and tissues: Plant cells have rigid cell walls made of cellulose, chloroplasts for photosynthesis, and large central vacuoles. Primary meristems produce primary tissues: protoderm (dermal), ground meristem (ground tissue), and procambium (vascular tissue). Dermal tissue forms the epidermis and, in many plants, a cuticle; ground tissue fills most of the plant body and carries out photosynthesis, storage, and support; vascular tissue conducts water, minerals, and sugars and includes xylem and phloem.

Growth and development: Primary growth lengthens roots and shoots through apical meristems at tips. Secondary growth increases the girth of many stems and roots in dicotyledons and gymnosperms via lateral meristems: the vascular cambium, which adds xylem and phloem, and the cork cambium, which produces protective bark.

Roots, stems, and leaves: Roots anchor the plant and absorb water and nutrients, often with root hairs to increase surface area. Stems provide support and transport and may bear nodes and internodes where leaves originate. Leaves are the main photosynthetic organs and contain tissues such as the mesophyll, with stomata regulating gas exchange and water loss.

Reproduction and variation: Many plants reproduce sexually via flowers, seeds, and fruits, while some also propagate vegetatively. Vascular plants are divided into seedless and seed plants; seed plants include gymnosperms and angiosperms, with diverse leaf forms and venation patterns.