8. Transport in Plants (Part 1) (Cambridge IGCSE Biology 0610 for exams in 2023, 2024 and 2025)

Summary

This IGCSE study video explores the transport system in plants, focusing on the roles of xylem and phloem. It explains how xylem vessels, with lignin-strengthened walls, transport water and minerals upwards, while phloem carries food to non-photosynthesizing parts. The video also covers the identification of these tissues in plant sections and demonstrates water uptake and transport through an experiment with dyed water and celery, providing a visual understanding of the plant's vascular system.

Takeaways

• 🌿 The video is part of a series on the Cambridge IGCSE biology syllabus, focusing on 'Transport in Plants'.
• 🔁 Plants have a transport system for nutrients and water, essential for their growth and function.
• 💧 Xylem and phloem are the two main transport vessels in plants, responsible for moving water, minerals, and nutrients.
• 🚰 Xylem transports water and mineral ions from the roots to the rest of the plant and provides structural support.
• 🌱 The structure of xylem vessels is adapted for efficient water transport with continuous tubes and thickened walls with lignin.
• 🍬 Phloem transports food, such as sucrose and amino acids, from the leaves to non-photosynthesizing parts of the plant.
• 🔠 A mnemonic to remember the function of phloem is that it starts with 'ph', similar to the sound of 'fur', which is associated with food.
• 🌳 Vascular bundles, containing xylem and phloem, are found throughout the plant, including roots, stems, and leaves.
• 📐 In diagrams, xylem is typically depicted on the inside and phloem on the outside of a cross-section.
• 🌱 Root hairs are specialized cells that increase the surface area for water and mineral absorption from the soil.
• 🚰 The pathway of water in a plant includes absorption by root hair cells, movement through the cortex, and transport via xylem to leaves.
• 🎨 An experiment using food dyes in water can visually demonstrate the movement of water through the xylem vessels in plants.

Q & A

What is the main purpose of the transport system in plants?

The main purpose of the transport system in plants is to carry nutrients within the plant, including water from the soil to the stem and leaves, and to distribute the nutrients produced by photosynthesis to other regions of the plant like stems and roots.

What are the two types of transport vessels in plants?

The two types of transport vessels in plants are the xylem and the phloem.

What substances does the xylem transport and what is its additional function?

The xylem transports water and mineral ions from the roots to the stem and leaves, and it also provides structural support to the plant.

How is the structure of xylem vessels adapted to their function of transporting water?

The xylem vessels have no cell contents, are joined end to end with no cross walls, forming a long continuous tube, and their walls are thickened with lignin for strength and to prevent collapsing, allowing water to pass easily.

What substances does the phloem transport and to which parts of the plant?

The phloem transports food substances, such as sucrose and amino acids, made by the plant from photosynthesizing leaves to non-photosynthesizing regions in the roots and stem.

How can you remember which vessel carries food and which carries water?

You can remember by the first sound; 'phloem' starts with the sound 'fur' and it carries food, which also starts with the 'fur' sound, while 'xylem' carries water.

What are vascular bundles and where are they located in a plant?

Vascular bundles are the collective term for xylem and phloem vessels and are found throughout the root, stem, and leaves of a plant.

In a cross section of a root, where is the xylem located relative to the phloem?

In a cross section of a root, the xylem is located on the inside in the shape of an X, and the phloem is the surrounding green area.

What are root hairs and how do they contribute to water uptake?

Root hairs are long extensions found on root hair cells, which are specialized cells in the roots of plants adapted to absorb water and minerals from the soil. They increase the surface area for increased uptake of water and mineral ions.

What is the pathway of water from the root hair cells to the mesophyll cells?

Water first enters the root hair cells from the soil through osmosis, then passes into the root cortex cells, travels up the xylem in the stem, and finally enters the mesophyll cells in the leaves.

How can you visually demonstrate the pathway of water in the above-ground parts of a plant?

By placing a plant like celery into beakers of water, one plain and two with different food dyes, and then observing the cross sections of the celery stalks after a few hours in sunlight, you can see the specific areas highlighted by the dyes in the xylem vessels, indicating the pathway of water.