Here is a time-lapse of a runner bean germinating underground. This is an example of Epigeal germination where the cotyledons expand, throw off the seed shell and become photosynthetic above the ground.
Beans like other seeds need temperature and moisture to stimulate germination.
Stage 1:
Radicle expands and pushes against the testa at the micropyle
Testa spilts open and radicle emerges
Lateral roots develop
Root hairs form behind tip of radicle which helps absorb water and mineral salts in the soil
Stage 2
Stem below cotyledons elongates
Pulling cotyledon through soil and above the ground
Sometimes the is testa remains underground or discarded above ground
Cotyledons are closed together to protect the delicate pumule within
Stage 3
Cotyledons open up above ground
Cotyledons turn green
First foliage leaves start to develop
Foliage expands and turns green carrying out photosynthesis
Runner bean seedling is now a self-supporting plant
I’ve filmed a shart sequence to show what happens to a bud when you prune a rose branch.
Basically you prune to get rid of any weak or diseased branches, to encourage healthy new growth and to keep the plants size and shape in check
Plants have evolved to be ‘pruned’ by herbivores grazing on them. Being nibbled stimulates new growth. In most gardens we don’t have herbivores to graze our plants so we need to prune them instead.
Here is a time lapse of a Broad bean showing hypogeal germination and root growth. Hypogeal ‘Hypogeal’ means ‘underground’. This is when the cotyledons of the germinating seed / bean remain below ground. salts in the soil. Roots and root hairs The main functions of root are: Absorption of water and nutrients, Fixation of the plant to […]
Posted by Neil Bromhall 
Posted by Neil Bromhall 
Posted by Neil Bromhall 
