external parts of plants Flashcards
What is a rhizome? State TWO ways in which a rhizome differs from a root.
Rhizome is what we can find underground, it’s not a root, but a stem. It differs from a root by spreading horizontally not vertically. More particularly, roots go down deeper underground than rhizomes. It is used by herbaceous perennials to spread.
Roots absorb water and nutrients into the plant. Rhizomes store water and nutrients.
What are three functions of stems?
- Hold flowers and leaves in an optimal position (e.g. for photosynthesis)
- Usually large parts of the stems are made up by vascular tissue to transport water and nutrients between roots and leaves.
- Green stems can do photosynthesis
What are the functions of root hairs?
Root hairs increase the surface area of the root and therefore allow more intake of water and nutrients.
Describe how external plant structure characteristics can be used to identify plants, to various taxonomic levels: e.g. family, genus, species. Provide THREE named examples.
Shape of the leaves and the pattern of the veins. For example the Iris genera has parallel veins and a linear leaf shape.
Bark has lenticels and is white/silvery in colour. For example Betula pendula.
Specific form and arrangement of buds. For example the rosaceae family has a specific form of buds which are called thorns (modified stems.
Weed control is an issue in almost every garden. Many plants create problems of competition to the plants we want to grow. What are THREE external characteristics of weed plants that can make them competitive, and therefore problematic? Give one named example from your own experience.
Fast spreading rhizomes. Fallopia japonica.
Self Seeding. Plants with a high seed production can spread quickly. E.g Taraxacum officinale
Rapid growth and therefore being very tall, big leaves, etc. This leads to taking light from other plants.
