23.3 Stems
What are three main functions of stems?- How do primary growth and secondary growth occur in stems?
node • bud • vascular bundle • pith • primary growth • secondary growth • vascular cambium • cork cambium • heartwood • sapwood • bark
Preview Visuals Before you read, preview the art in Figure 23–14. Define any familiar terms in your own words, and list any unfamiliar ones. Revise and add to your definitions as you read.
THINK ABOUT IT While visiting the salad bar for lunch, you notice an intriguing range of offerings. After making your basic salad, you decide to add some sliced water chestnuts and bamboo shoots on top. Then you serve yourself some asparagus and potato salad on the side. These good things are all from plants, of course, but can you think of something else that ties them together? They all come from the same part of the plant. Do you have any idea which part?
Stem Structure and Function
What are three main functions of stems?
What do water chestnuts, bamboo shoots, asparagus, and potatoes all have in common? They are all types of stems. Stems vary in size, shape, and method of development. Some grow entirely underground; others reach high into the air. Aboveground stems have several important functions: Stems produce leaves, branches, and flowers; stems hold leaves up to the sun; and stems transport substances throughout the plant.
Stems make up an essential part of the water and mineral transport systems of the plant. Xylem and phloem form continuous tubes from the roots through the stems to the leaves. These vascular tissues link all parts of the plant, allowing water, nutrients, and other compounds to be carried throughout the plant. In many plants, stems also function in storage and aid in the process of photosynthesis.
FIGURE 23–10 Cactus Stems Desert cacti have thick green stems that carry out photosynthesis and are adapted to store water.
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis