Plant Structure, Growth, and Development By: Emily, Lauren, and Rebecca
Plasticity: where a plant is able to mold itself due its environment Morphology: is the plants external form Tissues: a group of cell with common function and structure Organs: many tissues that work together to preform work Protoplast: area of cell not including the cell wall (able to determine function) Plants
Root System: portion of plant responsible for absorbing water and nutrients Root: the organ that anchors the plant, absorbs water and nutrients Taproot v. Lateral roots: Taproot: the main vertical root which developed from the embryonic root (Taproot system) Lateral roots: or Branch roots which are the roots coming off of the taproot and acts as a storage area Fibrous Root System: usually has no main root but a bunch of small roots Adventitious: where there is growth in an unusual area Root hairs: small root growth Plant Organs: Roots, Stems, and Leaves
Stem: an organ of the plant that support the leaves Nodes: where stem and leaf attatch Internodes: the segments of stem between the nodes Terminal bud: embryonic tissue located at the tip/top of the plant Axillary bud: the bud that is able to form a branch Apical Dominence: where the growth of the main stem (the terminal bud) is dominant over the apical buds Stems http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/apical_dominance.jpg
Leaf: organ that preforms photosynthesis Petiole: joins the leaf to the stem Blade: the flat part of the leaf Vein: similar, but not as complex veins that are in humans Leaves
Tissue System: where one or more tissues interact as a functional unit Dermal Tissue System Epidermis: the outer protective layer in plants Periderm: another protective layer that replaces the epidermis Cuticle: the waxy coating Vascular Tissue System Xylem: cells (mainly dead) that move H20 and minerals up from the roots Phloem: transports sugar Stele: the vascular tissue in stem and root Vascular cylinder: the tissue that forms a column in the roots Vascular bundles: the stele in leaves and stems Ground Tissue System Serves as filler, support and storage Pith: the ground tissue that is in the vascular tissue Cortex: external ground tissue to the vascular tissue The Three Tissue Systems: Dermal, Vascular, and Ground
Indeterminate growth: continuous growth in plants (during entire lifetime) Meristems: tissues that enable plants to continuously grow - Apical meristem: at tips and roots Primary growth: the plant grows in length Secondary growth: growth in thickness (bark) (through lateral meristems) -Vascular cambian: secondary layers of vascular tissues -Cork cambian: where periderm replaces the epidermis (tougher) Plant life Annuals: die in a year. Biennials: die in 2 years Perennials: live many years... Herbaceous: no wood (all primary growth) Plant Growth
Initials: the cells at the meristems that remain as meristems to continually produce new cells Derivatives: cells that are produced by the apical meristems and become differentiated
Root Cap - protects the apical meristem as the root pushes through soil during primary growth. Growth occurs in three zones of cells at successive stages of primary growth. From the root tip up, the zones are cell division, elongation, and maturation Primary Growth Lengthens Roots and Shoots
Primary growth roots produces the epidermis, ground tissue, and vascular tissue.
Primary Growth of Shoots leaves arise as leaf primordia, finger–like projections along the flanks of the apical meristem
Eudicot vs. Monocot Eudicots - the vascular tissue consists of vascular bundles arranged in a ring. The xylem in each vascular bundle faces the pith, and the phloem faces the cortex. Monocot - the bundles are scattered throughout the ground tissue, rather than forming a ring (Figure35.16b ). In both monocot and eudicot stems, ground tissue consists mostly of parenchyma
Tissue Organization of LeavesThe epidermal barrier is interrupted by the stomata, which allow CO2 exchange between the surrounding air and the photosynthetic cells inside the leaf. stoma - the stomatal pore consisting of a pore flanked by two guard cells
Secondary growth adds girth to stems and roots in woody plants Secondary growth, the growth in thickness produced by lateral meristems, occurs in stems and roots of woody plants. The secondary plant body consists of the tissues produced by the vascular cambium and cork cambium.
The Vascular Cambium and Secondary Vascular Tissue The vascular cambium is a cylinder of meristematic cells one cell thick. In this way, it is primarily responsible for the thickening of a root or stem. In a typical gymnosperm or woody eudicot stem, the vascular cambium forms in a layer between the primary xylem and primary phloem of each vascular bundle
heartwood - the older layers of secondary xylem no longer transport water and minerals (xylem sap). sapwood - The outer layers still transport xylem sap. Heartwood is generally darker than sapwood because of resins and other compounds that clog the cell cavities and help protect the core of the tree from fungi and wood–boring insects.
Plant Body Production: Growth, Morphogenesis, and Differentiation • Morphogenesis: The development of body form and organization. It's all about gene expression and gggrrrrrrowth! • Systems Biology: An approach to studying biology that aims to model the dynamic behavior of the whole biological systems. • The most commonly studied plant is Arabidopsis thaliana. • The entire genome has been sequenced! • Mmm... Mustard
Growth: Cell division increases potential for growth, but it is growth that increases mass! The plane of cell division affects the plantform: Parallel to previous= single file of cells On multiple planes= cube. Random= disorganized clump of cells. Asymmetrical Cell division: Uneven distribution of cytoplasm. Signals a key event in development. Growth
Large vacuole: Water is 90% of growth. The plan of cell division is determined by the preprophase band. Orientation determined by cellulose microfibrils. Growth
Morphogenesis and Pattern Formation • Pattern formation: the development of specific structures in specific places. • Positional Information: Signals to which genes regulating development respond, indicating a cell's location relative to other cells in an embryonic structure. • Polarity: the condition of having structural differences at opposite ends of an organism.
Phase Changes=Plant Puberty! • Phase changes: The morphological changes that arise from transitions from a juvenile phase to an adult phase. • usually changes in the leaves and stems • juvenile meristems can keep growing juvenile shoot's and leaves if a node forms... even after the apical meristem is mature!
Meristem identity genes ABC Model Genetic Control of Flowering