Transport in plants - B8

Waxy cuticle

The top part of leaf designed to prevent water loss due to evaporation

Upper epidermis

It is transparent as it doesn’t contain any chloroplasts to let light reach the palisade mesophyll and also acts as a barrier from pathogens.

Palisade mesophyll layer

The layer where all the palisade cells are located and where photosynthesis occurs.

spongy mesophyll layer

The layer where carbon dioxide enters and oxygen leaves which is used for photosynthesis.

lower epidermis

layer before stomata.

guard cells

The cells responsible for letting oxygen and carbon dioxide in by controlling the opening and closing of the stomata.

stomata

The open space between guard cells

Transpiration

The evaporation of water from the leaves of a plant.

Translocation

Translocation is the movement of dissolved sugars up or down a phloem.

The four factors that affect the rate of transpiration

wind speed, light intensity, humidity and temperature are factors that affect the rate of respiration

What does the xylem transport

The xylem transports water and dissolved mineral ions

What does the phloem transport

the phloem transports sugars and cell sap which is a mixture of water and sugar.

What are sinks

Sinks are organs that use sugars or cell sap.

What are sources

Sources are organs that release sugars and cell sap for other organs.

What is lignin

Lignin is the substance on the outer part of the xylem required to strengthen and harden the xylem.

Why does the phloem have pores

The phloem has pores so it is able to control the direction of translocation stream(up or down)

Companion cells

Companion cells give the phloem the energy to transport cell sap (sugars) and amino acids.