Slide 1
Many cacti open their pores in the cooler night
Many cacti take in carbon dioxide mainly at night. Opening their pores in cooler air helps limit water loss.
More to Read
The pores are called stomata. When they open for gas exchange, water can escape from moist inner surfaces into the drier air. Opening time therefore matters in an arid habitat.
Slide 2
Stored carbon supplies the plant during daylight
Crassulacean acid metabolism (CAM) lets cacti store carbon taken in at night in organic acids. They can then use that supply during daylight.
More to Read
CAM lets the cactus take in and store carbon at night, then use it during the day. Sunlight still powers photosynthesis; the cactus does not make all its food at night.
Slide 3
Green stems both make food and store water
Many cacti have green, water-storing stems and reduced leaves. Their stems combine photosynthesis with a reservoir for dry periods.
More to Read
Spines are modified leaves rather than ordinary branches. Their functions can include defence and shading, while the broad photosynthetic surface has shifted to the stem in many species.
Slide 4
Stored water bridges the gaps between rain
A cactus benefits from taking up water when rain arrives. Its stored supply helps it remain alive between wet periods.
More to Read
Storage has limits, and drought tolerance does not mean unlimited survival without rain. Growth and reproduction still depend on resources accumulated under favourable conditions over the plant's lifetime.
Slide 5
Water-saving growth does not suit every environment
Conserving water allows cacti to occupy dry habitats. It does not make their way of growing ideal in every environment.
More to Read
Restricting daytime gas exchange can constrain carbon intake. Plant strategies balance resource gain and loss, which helps explain why different habitats support different combinations of leaves, stems and growth rates.
Sources
- Cacti and Desert Succulents
National Park Service
- Cacti and Desert Succulents
National Park Service