Question

Описать каждые функции внутренние части стебля​

Answer 1

Ответ:

Внутрішня будова стебла

Розглянемо особливості  внутрішньої будови стебла, які дають йому змогу виконувати певні функції.  На поперечному зрізі гілки липи добре видно шари стебла. Зовнішній, вузький шар  - це кора. Щільний, найширший, розміщений під корою - деревина.  Між корою і деревиною є особливий шар клітин - камбій. У центрі стебла знаходиться серцевина.

Для  детальнішого вивчення внутрішньої будови стебла необхідно розглянути поперечний зріз гілки липи під мікроскопом.

Объяснение:

Стебла бувають:

1. Трав'янисті (у всіх трав), дерев'янисті (дерева, чагарники, чагарнички),   напівдерев'янисті  (полин).

2. За напрямком росту та розташуванням у просторі: прямостоячі, повзучі,   чіпкі, виткі.

3. За формою поперечного зрізу: циліндричні або округлі (соняшник), тригранні (осока), чотиригранні (кропива), багатогранні (щавель), борозенчасті (татарник).

4. За тривалістю життя: однорічні, дворічні, багаторічні.

Answer 2

Functions and Internal Parts of a Stem

The stem is an essential part of a plant that provides support and transports water, nutrients, and sugars between the roots and leaves. It consists of various functions and internal parts that work together to ensure the plant's growth and survival. Let's explore each of these functions and internal parts in detail:

1. Support: The primary function of the stem is to provide support to the plant. It keeps the plant upright and allows it to reach towards sunlight for photosynthesis. The stem's structure, including its rigidity and flexibility, helps the plant withstand external forces such as wind and gravity.

2. Transport: The stem acts as a transportation system within the plant, facilitating the movement of water, nutrients, and sugars between the roots and leaves. This transport occurs through specialized tissues called xylem and phloem.

- Xylem: The xylem is responsible for transporting water and minerals from the roots to the leaves. It consists of long, hollow cells that form a continuous network throughout the stem. Water moves through the xylem via capillary action and transpiration pull. - Phloem: The phloem transports sugars, hormones, and other organic compounds from the leaves to other parts of the plant. It consists of living cells called sieve tubes, which are connected end-to-end to form a sieve tube element. The movement of substances in the phloem occurs through a process called translocation.

3. Storage: Some stems have the ability to store water, nutrients, and sugars. These storage stems are often modified and can serve as a reservoir during periods of drought or when resources are scarce. Examples of storage stems include rhizomes, tubers, and bulbs.

4. Vegetative Propagation: Certain plants can reproduce asexually through vegetative propagation, where new plants are produced from specialized structures on the stem. These structures, such as runners, stolons, and suckers, allow the plant to clone itself and produce offspring without the need for seeds.

5. Protection: The stem plays a role in protecting delicate internal tissues of the plant. It is covered by a protective layer called the epidermis, which helps prevent water loss and acts as a barrier against pathogens and pests. Some stems also have thorns, spines, or prickles that deter herbivores from feeding on the plant.

Internal Parts of a Stem: The internal structure of a stem consists of various tissues and parts that contribute to its functions. These include:

- Epidermis: The outermost layer of cells that covers the stem and provides protection. - Cortex: The region between the epidermis and vascular tissues, consisting of parenchyma cells that store nutrients. - Vascular Bundles: These are clusters of xylem and phloem tissues that run through the stem. They are responsible for the transport of water, nutrients, and sugars. - Pith: The central region of the stem, composed of parenchyma cells. It provides support and stores nutrients. - Cambium: A layer of meristematic tissue that lies between the xylem and phloem. It is responsible for the growth in girth of the stem through cell division. - Secondary Growth Tissues: In some plants, the stem undergoes secondary growth, resulting in an increase in girth. This growth is facilitated by the activity of the vascular cambium and cork cambium, which produce secondary xylem (wood) and cork, respectively.

These are the main functions and internal parts of a stem. Each plant species may have variations in stem structure and function based on its specific adaptations and requirements.