Plant Stems Flashcards
Four functions of stems
-hold the leaves in the best position to catch sunlight for photosynthesis
-hold flower in best position for pollination to occur
-vessels xylem and phloem transport substances around plant
-green cells carry out some photosynthesis
What are vascular plants
Plants with specialised transport systems
What is transported around plants
Carbon dioxide, oxygen, water, organic nutrients(AAs and glucose), inorganic ions(nitrate, phosphorus, potassium)
What is in a vascular bundle and structure
Xylem on inside and phloem on outside then cambium in between xylem and phloem and sclerenchyma cap
Epidemis
Outer layer of stem which does not support but protects the cells beneath it
What is cambium
Found in between xylem and phloem in vascular bundles
Role of xylem
Transport water and mineral ions up plant in transpiration stream
What is cutin
Waxy substance secreted from epidermis to reduce water loss from the plant
Why do some plants produce hairs on stem
to help trap warm air and keep plant warm
What is lignin
Protein that makes wood so is very strong and waterproof
Role of lignin in xylem
to strengthen xylem vessel and stop water leaking out as is waterproof
What are non-lignified pits in xylem
Thin layers of cell wall that allows lateral movement of water between cells
What are sclerenchyma
Provides structural stability for cell and is dead, contains lignin in walls
Role of phloem
Moves sugar up and down plant via translocation
Why does sieve tube element not have many organelles
No nucleus and few organelles and thin layer of cytoplasm means more space for sugar to move through and companion cells carry out the living functions for themselves and the sieve tube element
