Final answer:
Celery stems contain xylem and phloem, which transport water, minerals, and nutrients throughout the plant. Dandelions and other plants have very short stems forming a rosette, with biennials bolting in their second year to grow elongated stems for flowering. Understanding plant stem functions is crucial for botany and agriculture.
Step-by-step explanation:
Stems are an essential part of a plant's structure and function, pathways for transporting vital substances throughout the organism. In the case of a celery stalk, it contains bundles of xylem and phloem that are parts of the plant's vascular system, similar to our circulatory system. The xylem is responsible for transporting water and minerals from the roots to the rest of the plant, while phloem moves the sugars and other nutrients produced by the plant during photosynthesis.
Plants such as the dandelion have what is known as a 'rosette' formation due to their very short stems, causing the leaves to cluster closely. This structure allows the dandelion to maximize its growth in a compact form. In contrast, some plants can appear to be stemless as they spread their leaves horizontally close to the ground, but they indeed have stems, albeit very reduced in length. Biennials, including many common agricultural crops and weeds, exhibit a two-year life cycle where they form a rosette in their first year and then 'bolt' in the second year— elongating their stems to produce flowers.
Understanding the role of the stem and its associated vascular tissues is key to knowing why and how plants transport substances, as well as why certain plants display distinct growth forms like rosettes and bolting behaviors. This information is fundamental in the fields of botany, horticulture, and agricultural science.