Growth

Meristem is the tissue in plants that give growth and form organs such as flowers and leaves. The meristem cells can divide continuously and are all the same. They make the basic structure for the plant and help with differentiation in tissues and making new organs.

There are three types of meristems:

• apical
• intercalary
• lateral

Apical: at tips of stems and roots to increase length at tips and for growth

Intercalary: Between the tip and base of stems and leaves to increase length between nodes

Lateral: at sides of stems and roots to increase diameter

 

Primary growth: happens in all vascular plants. It is the growth of roots and stems in length.

Secondary growth: is more common in dicots such as beans. Secondary growth is the increase of diameter in roots and stems.

Vascular cambium:

• make up secondary vascular tissues (sec. xylem and sec. phloem)

• transport water solutions
• lateral meristem
• between tissues of stem and root, sometimes in leaves

Cork cambium:

• tissue that's part of periderm in vascular plants
• lateral meristem
• secondary growth that replaces epidermis in roots and stems
• produces the cork, protective layer
• layer of bark

Plant Hormones:

• Auxin: located in- embryo of seeds, young leaves, meristems of apical buds

function- stimulates ceel elongation, vascular differentiation, induces adventitious roots on cuttings, involved in phototropism, gravitropism, stimulates ethylene synthesis, ect.

• cytokinin: located in- synthesized in roots and transported to other organs

                           function- Stimulates cell division, involved in shoot growth, delay leaf sequence

Tropism: The whole plant is leaning towards the sunlight.