Download - 13.5 Plant Growth and Development
13.5 Plant Growth and Development
Pages 605-612
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 germinateExample: lilly
Photoperiod
• Plants respond to daylength• Timing of flowersExample: Spinach- long daylengthExample: 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