Plant Structure, Growth, and Development
Chapter 35
Plant Structure, Growth, and Development
Lecture Outline
Overview: Plastic Plants?
• The fanwort, an aquatic weed, demonstrates the great developmental plasticity that is characteristic of plants. o The fanwort has feathery underwater leaves and large, flat, floating surface leaves. o Both leaf types have genetically identical cells, but the dissimilar environments in which they develop cause different genes involved in leaf formation to be turned on or off.
• In addition to plastic structural responses of individual plants to specific environments, plant species have adaptations in morphology that benefit them in their specific environments. o For example, cacti have leaves that are reduced to spines and a stem that serves as the primary site of photosynthesis. These adaptations minimize water loss in desert environments.
• The form of any plant is controlled by environmental and genetic factors. As a result, no two plants are identical.
• Angiosperms make up 90% of plant species and are at the base of the food web of nearly every terrestrial ecosystem.
• Most land animals, including humans, depend on angiosperms directly or indirectly for sustenance.
Concept 35.1 The plant body has a hierarchy of organs, tissues, and cells.
• Plants, like multicellular animals, have organs that are composed of different tissues, and tissues that are composed of different cell types. o A tissue is a group of cells with common structure and function. o An organ consists of several types of tissues that work together to carry out particular functions.
Vascular plants have three basic organs: roots, stems, and leaves.
• The basic morphology of vascular plants reflects their evolutionary history as terrestrial organisms that inhabit and draw resources from two very different environments. o Vascular plants obtain water and minerals from the soil. o Vascular plants obtain CO2 and light
Plant Structure, Growth, and Development
Lecture Outline
Overview: Plastic Plants?
• The fanwort, an aquatic weed, demonstrates the great developmental plasticity that is characteristic of plants. o The fanwort has feathery underwater leaves and large, flat, floating surface leaves. o Both leaf types have genetically identical cells, but the dissimilar environments in which they develop cause different genes involved in leaf formation to be turned on or off.
• In addition to plastic structural responses of individual plants to specific environments, plant species have adaptations in morphology that benefit them in their specific environments. o For example, cacti have leaves that are reduced to spines and a stem that serves as the primary site of photosynthesis. These adaptations minimize water loss in desert environments.
• The form of any plant is controlled by environmental and genetic factors. As a result, no two plants are identical.
• Angiosperms make up 90% of plant species and are at the base of the food web of nearly every terrestrial ecosystem.
• Most land animals, including humans, depend on angiosperms directly or indirectly for sustenance.
Concept 35.1 The plant body has a hierarchy of organs, tissues, and cells.
• Plants, like multicellular animals, have organs that are composed of different tissues, and tissues that are composed of different cell types. o A tissue is a group of cells with common structure and function. o An organ consists of several types of tissues that work together to carry out particular functions.
Vascular plants have three basic organs: roots, stems, and leaves.
• The basic morphology of vascular plants reflects their evolutionary history as terrestrial organisms that inhabit and draw resources from two very different environments. o Vascular plants obtain water and minerals from the soil. o Vascular plants obtain CO2 and light