Plant system

• Like animals, plants need to exchange gases with their surrounding.
• Plants require an internal transportation system to move water and nutrients around like animals.
• Shoot system: photosynthesis, transport of food and water, preproduction, storage and response
• Root system: anchorage, absorption of water and minerals, transport of food and water, reproduction, storage, and response.
• Root system is made up of one or more separate roots
• The shoot system is made up of stem, leaves, etc
• Root system: contains root hairs (tiny extensions of tissue which help in absorption)
• Root system function: anchors plant, absorbs water and minerals, stores food
• Shoot system: system specialized to conduct photosynthesis and reproduce sexually (made of 3 parts - leaf, flower, and stem)
• Plant tissue: a tissue is a group of cells working together to perform a similar function.
• The cells in tissues are specialized to perform specific functions. All these cells develop from unspecialized cells during cellular differentiation.
• Unspecialized cells in animals are called stem cells
• In plants, unspecalized cells are called meristematic cells
• A region of a plant that is rich in meristem cells is called the meristem region
• Meristem cells are capable of division and growth in plants (repair injured plant tissue, and growth of plant)
• Plants have 3 major tissue types: dermal, vascular, and ground.
• Dermal covers outer surface of plant
• Vascular is found in every root, shoot and leaf. System is continuous (all plant parts joined by vascular tissue).
• Vascular tissue is the transportation system that moves water, minerals, and over chemicals around the plant.
• Ground tissue is all the other tissues in the plant (leftovers)
• There are 2 types of vascular tissues, xylem and phloem.
• Xylem transports water and dissolved minerals from the roots to the leaves and stem
• Phloem transports dissolved food materials and hormones throughout the plant.
• Xylem transports water and dissolved minerals upwards from roots. Cells are hollow tubers with rigid walls and no organelles (allows for easier transportation of water). Mature xylem cells are not considered living tissue.
• Phloem transports sugars produced by photosynthesis and hormones. Phloem can move sugars downwards from leaves and stems or upwards from roots. Phloem cells are alive when functioning.
• Ground tissue is the filler between dermal and vascular tissue. Functions: in green parts of plant, they manufacture nutrients via photosynthesis. In stems, they provide storage and support. In roots, they store carbohydrates.
• Because sugar is so important to all components of a plant, it must have a system to transport sugar. Oxygen is also required by plant cells for cellular respiration. Leaves produce more 02 than needed and excess is released as waste.
• Chloroplasts are contained in mesophyll layers(in ground tissue) - palisade mesophyll is located where there is maximum light. Spongy mesophyll is located throughout leaf with air pockets in between.
• CO2 will naturally diffuse into a leaf. To avoid too much diffusion, the leaf is coated with a layer of epidermal tissue called the cuticle.
• Gases enter and exit through openings in the leaf called stomata.
• Stomata are controlled by guard cells(dermal tissue)
• Leaves will close stomata when water levels are low.
• Leaves obtain water through vascular bundles and run from root to leaf. Root hairs (epidermal) grow into soil from roots and obtain water via diffusion. Water is transferred via xylem from roots to leaves.