The Plant Body PDF

The Plant Body Flowering plants have two main organs systems : the shoot system )leaves, stem, flowers, fruits( and the root system.)which absorbs water and minerals(.The shoot system grows above grou...

The Plant Body Flowering plants have two main organs systems : the shoot system )leaves, stem, flowers, fruits( and the root system.)which absorbs water and minerals(.The shoot system grows above ground, where it absorbs light for photosynthesis The root system is typically underground Plant Tissues A tissue is a group of cells with similar structure and function There are two main types of plant tissues. Meristematic tissue: Immature cells that actively divide, found in stem and root apices,.leaf primordia, and vascular/cork cambium.They contribute to plant growth Permanent tissue: Mature cells that have stopped dividing These are further classified into different types Meristematic Tissue Characteristics Composed of immature cells Lack intercellular spaces Thin-walled cells Cells rich in cytoplasm with small vacuoles Classification of Meristems Based on origin Primary (derived from promeristem, found at stem and root apices) and secondary (develops from permanent tissues, adds to thickness through secondary growth; examples )include cork cambium and interfascicular cambium Based on position )Apical (tips of roots and stems, for longitudinal growth , intercalary (between permanent tissues, increasing internode length),  and lateral (laterally on roots and stems, increasing thickness) * * Based on function Protoderm (forms epidermis )procambium (forms primary vascular tissues , and ground meristem (forms cortex and pith). Permanent Tissues Epidermis Outermost layer, provides protection, absorbs water and minerals in roots, regulates water loss through transpiration in stems and leaves (via stomata). May contain trichomes (hair-like structures). Parenchyma Thin-walled cells with various functions (photosynthesis, storage). Types include.)aerenchyma (air spaces) and chlorenchyma (chlorophyll Collenchyma Thick-walled cells with cellulose deposits, providing primary support in herbaceous plants Sclerenchyma Dead cells with heavily thickened secondary walls containing lignin, providing support. Types include fibers (elongated) and sclereids Vascular Tissue  Xylem transports water and minerals from roots) and phloem )transports organic compounds from sites of photosynthesis( Xylem contains tracheids and vessel elements. tubular and elongated, dead at maturity), while phloem contains sieve tubes (alive at( )maturity.and companion cells