Question

Long Answer Questions:
1. Describe the structure of (a) xylem (b) phloem​

Answer 1

• Plants lack a regular circulatory system like animals have we all know that plants prepare their food from carbon dioxide and water in their leaves.

• The other materials present in plant body like nitrogen, phosphorus and minerals are taken directly from the soil.

• The conduction of some materials to short distances occurred through diffusion while for longer distances a need of proper transportation arises.

• Therefore two pathways have developed in plants independently which comprise of xylem tissues and phloem tissues.

• Both xylem and phloem carry substances from one part of the plant body to another.

• Xylem transports water and minerals obtained from the soil.

• Phloem transports products of photosynthesis from leaves to other parts of the plants.

• Xylem tissues of plants have interconnected network of a vessels and tracheids of roots, stems and leaves.

• They form continuous system of water conducting channels which reaches all parts of the plant.

• At the roots cell in contact with the soil actively take up ions creating a difference in the concentration of these ions between the roots and soil.

• The water that enters into routes from soil eliminate this difference that is by making the concentrations equal.

• Hence there is a steady movement of water into root xylem from the soil that creates a column of water putting it upwards.

• Another strategy used by plants to move water upward in xylem over highest points of plant is transpiration that is loss of water from stomata.

• The water which is lost to the stomata is replaced by water from the xylem vessels in the leaf.

• Evaporation of water molecules from leaves self create a suction which pulls water from the xylem cells of the root.

Answer 2

Answer:

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xylem

is made up of several types of cells. Tracheids are long cells that help transport xylem sap and also provide structural support. Vessel elements are shorter than tracheids, but also help conduct water. They are found in flowering plants, but not in gymnosperms like pine trees. Vessel elements have perforation plates that connect each vessel element to form one continuous vessel. Xylem also contains parenchyma, a tissue that makes up most of the soft parts of plants, and long fibers that help support the plant. In a cross section of a plant, under a microscope, xylem appears star-shaped

Explanation:

Xylem is a type of tissue in vascular plants that transports water and some nutrients from the roots to the leaves. Phloem is the other type of transport tissue; it transports sucrose and other nutrients throughout the plant. Xylem and phloem give vascular plants their classification; they are the vascular tissues that transport substances throughout the plant