A plant is built from organized groups of cells called tissues, and these tissues work together to form roots, stems, and leaves. Instead of thinking of a plant as a set of separate parts, biologists study it as three connected tissue systems: dermal, ground, and vascular. Each system has a different job, such as protection, photosynthesis, storage, support, or transport.
Understanding plant tissue systems helps explain how plants grow, survive damage, move water, and make food.
Key Facts
- The three plant tissue systems are dermal tissue, ground tissue, and vascular tissue.
- Dermal tissue covers the outside of the plant and helps protect it from injury, pathogens, and water loss.
- Ground tissue fills much of the plant body and is involved in photosynthesis, storage, and support.
- Vascular tissue includes xylem and phloem, which transport water, minerals, and sugars through the plant.
- Xylem mainly moves water and dissolved minerals upward from roots to stems and leaves.
- Phloem moves sugars from sources to sinks, such as from leaves to growing roots, fruits, or storage tissues.
Vocabulary
- Dermal tissue
- Dermal tissue is the outer protective tissue system of a plant, including the epidermis and specialized structures such as root hairs and stomata.
- Ground tissue
- Ground tissue is the tissue system that makes up much of the inside of roots, stems, and leaves and performs photosynthesis, storage, and support.
- Vascular tissue
- Vascular tissue is the transport tissue system made of xylem and phloem that moves water, minerals, and sugars through a plant.
- Meristem
- A meristem is a region of actively dividing plant cells that produces new tissues for growth.
- Xylem
- Xylem is vascular tissue that transports water and dissolved minerals from the roots toward the rest of the plant.
Common Mistakes to Avoid
- Thinking xylem and phloem do the same job, which is wrong because xylem mainly carries water and minerals while phloem carries sugars and other organic nutrients.
- Labeling all inner plant tissue as vascular tissue, which is wrong because much of the inside of stems, roots, and leaves is ground tissue used for storage, support, or photosynthesis.
- Forgetting that roots, stems, and leaves all contain the three tissue systems, which is wrong because each organ has dermal, ground, and vascular tissues arranged in different patterns.
- Assuming plant growth occurs everywhere equally, which is wrong because most new plant cells are produced in meristems such as root tips, shoot tips, and some lateral growth regions.
Practice Questions
- 1 A root tip grows 1.8 cm in 6 days. What is its average growth rate in cm per day?
- 2 A leaf cross-section has 30 epidermal cells, 120 ground tissue cells, and 20 vascular tissue cells in a sample. What percentage of the cells are ground tissue cells?
- 3 A student observes that a plant has wilting leaves even though the leaves can still make sugar. Which tissue system is most likely failing to deliver enough water, and why?