Learning Objectives During certain time periods or environmental circumstances, active growth is not advantageous for a plant. For example, the embryos in seeds must stay dormant for long enough to disperse from the parent plant or until there are suitable…
Learning Objectives Plants grown in the dark have elongated stems, are white or yellow (due to lack of chlorophyll), and have small leaves (Figures and 2). This phenomenon is called etiolation, and it is a mechanism that increases the chance that the…
Learning Objectives Detection of seasonal changes is crucial to plant survival. Although temperature and light intensity influence plant growth, they are not reliable indicators of season because they may vary from one year to the next. Day length is a…
Learning Objective Describe the environmental conditions that induce flowering. The flowering plants (angiosperms) go through a phase of vegetative growth producing more stems and leaves and a flowering phase where they produce the organs for sexual reproduction. In annuals the vegetative phase begins with…
Learning Objectives A tropism is directional growth in response to a stimulus. A positive tropism occurs when a plant (or a part of the plant) grows towards the stimulus, and a negative tropism is growth away from the stimulus. Phototropism is directional growth in response to light…
Photosynthesis and aerobic cellular respiration are two key metabolic pathways conducted by plants. The process of photosynthesis transformed life on Earth. By harnessing energy from the sun, photosynthesis evolved to allow living things access to enormous amounts of energy. Because…
Learning Objectives Different plant species have adaptations that allow them to do different variations of the light-independent reactions. These are called photosynthetic pathways. Plants are classified as C3, C4, or CAM depending on their use of these pathways, but note that…
Learning Objectives After the energy from the sun is converted into chemical energy temporarily stored in the bonds of ATP and NADPH molecules, the cell has the fuel needed to build carbohydrate molecules for long-term energy storage. The products of…
Learning Objectives How can light be used to make food? When a person turns on a lamp, electrical energy becomes light energy. Like all other forms of kinetic energy, light can travel, change form, and be harnessed to do work.…
Learning Objective Summarize the experimental results that revealed details about the process of photosynthesis. The history of the studies done on photosynthesis dates back into the 17th century with Jan Baptist van Helmont. He rejected the ancient idea that plants…