13.5 Plant Growth and Development Pages
Walking palm The adventitious roots in the shade die and new roots in the direction of the sun form.
Growth Increase in size
Differentiation A cell becomes specialized to perform a particular function.
Apical meristem found at the tips of plant’s buds, stems and roots. primary growth occurs here plant height increases
Lateral meristem found at the sides of plant’s buds, stems and roots. causes secondary growth increases the width of the plant
Primary Growth Apical meristem cells divide and elongate Differentiation into epidermal, parenchyma or vascular cell types.
Shoot apical meristem becomes stems, leaves and reproductive organs Root apical meristem has three zones: – Zone of maturation – Zone of elongation – Zone of cell division
Secondary growth Only in woody species after first year. Example: vascular cambium and cork cambium
Light Photoreceptor- a molecule that reacts when struck by light of a certain intensity and/or wavelength. Some seeds need light to germinate Example: lettuce Some seeds need darkness to germinate Example: lilly
Photoperiod Plants respond to daylength Timing of flowers Example: Spinach- long daylength Example: Tulip-short daylength
Macronutrients Large quantities (more than 1g/kg of dry mass) Examples: N, P, K
Carbon From carbon dioxide in the air Carbon backbone of organic molecules
Hydrogen From water
Oxygen From the air
Nitrogen Nitrates and ammonia Proteins, DNA, RNA, chlorophyll chlorosis
Phosphorus From hydrogen phosphite ion For DNA, RNA, membranes
Potassium From K+ ions For activation of enzymes and cellular transport
Calcium From calcium ion For cell walls, membrane transport
Sulfur From sulfate ion For proteins
Magnesium From magnesium ion For chlorophyll, enzyme activation
Micronutrients Nutrients needed less than 100 mg/kg of dry mass. B, Cl, Cu, Fe, Mn, Mo, Ni, Zn Used for Chlorophyll synthesis, cell division, enzyme production
Temperature Opening and closing stomata Timing of seed germination Timing of flowering
Soil Medium to anchor roots Retains water and nutrients Air pH