Plant cell organisation

Created by

ali G

Cards (17)

Plant cells are organised into tissues and organs
Plants are made or organs like stems, roots and leaves. Plant organs work together to make organ systems. These can perform the various tasks that a plant needs to carry out to survive and grow - e.g. transporting substances around a plant
Plant organs are made of tissues
Epidermal tissue - this covers the whole plant
Palisade mesophyll tissue - this is the part of the leaf where most photosynthesis happens
Spongy mesophyll tissue - this is in the leaf, and contains big air spaces to allow gases to diffuse in and out of cells
Xylem and phloem - they transport substances like water, mineral ions and food around the plant (through the roots, stems and leaves)
Meristem tissue - this is found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cell, allowing the plant to grow
The leaf is an organ made up of several types of tissue
Leaves contain epidermal, mesophyll, xylem and ploem tissues
Mesophyll = middle of a leaf
The epidermal tissues are covered with a waxy cuticle, which helps to reduce water loss by evaporation
The upper epidermis is transparent so that light can pass through it to the palisade layer
The palisade layer has lots of chloroplasts (the structures where photosynthesis takes place). This means that they're near the top of the leaf where they can get the most light
The xylem and phloem from a network of vascular bundles, which deliver water and other nutrients to the entire leaf and take away the glucose produced by photosynthesis. They can also support the structure
The tissues of leaves are also adapted for efficient gas exchange. E.g. the lower epidermis is full of little holes called stomata, which let CO2 diffuse directly into the leaf
The opening and closing of stomata is controlled by guard cells in response to environmental conditions. The air spaces in the spongy mesophyll tissue increase the rate of diffusion of gases