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