Arizona State University:.What part of the cactus photosynthesizes?

Although some of the steps in photosynthesis are still not completely understood, the overall photosynthetic equation has been known since the 19th century.

In what part of the cactus does the photosynthesis take place?

usually convert light into with a of 3–6%. Actual plants' photosynthetic efficiency varies with the frequency of the light being converted, light intensity, temperature and proportion of carbon dioxide in the atmosphere, and can vary from 0.1% to 8%. By comparison, convert light into at an efficiency of approximately 6–20% for mass-produced panels, and above 40% in laboratory devices.

Where does all this "photosynthesizing" take place?

The main source of in the is , and its first appearance is sometimes referred to as the . Geological evidence suggests that oxygenic photosynthesis, such as that in , became important during the era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor, which is to molecular oxygen (O2) in the .

and therefore is the type of photosynthesis used by cacti ..

(Cárdenas) D.R. Hunt 1987
Syn. Cárdenas 1951
Syn. (Cárdenas) Kimnach 1960

The long green stems with 14 - 17 ribs can grow upright as a shrubby plant for a while but tend to become prostrate, forming a tangled mat. The closely-spaced areoles produce 13 - 40 golden spines. Attractive tubular pink to red flowers with purple stamens are produced in early Summer. These flowers open wide which is why this cactus was originally classified as a The small fruits are red with white or brown wool.

Native to the Andean Valleys in the Department of Santa Cruz, Bolivia but common worldwide as it is used for dry landscaping in warm climates. Needs a cool Winter to flower freely.

and numerous other plants as cacti because of their succulent ..

The biochemical capacity to use water as the source for electrons in photosynthesis evolved once, in a of extant . The geological record indicates that this transforming event took place early in Earth's history, at least 2450–2320 million years ago (Ma), and, it is speculated, much earlier. Available evidence from geobiological studies of (>2500 Ma) indicates that life existed 3500 Ma, but the question of when oxygenic photosynthesis evolved is still unanswered. A clear paleontological window on cyanobacterial opened about 2000 Ma, revealing an already-diverse biota of blue-greens. remained principal throughout the (2500–543 Ma), in part because the redox structure of the oceans favored photoautotrophs capable of . joined blue-greens as major primary producers on near the end of the , but only with the (251–65 Ma) radiations of dinoflagellates, coccolithophorids, and diatoms did in marine shelf waters take modern form. Cyanobacteria remain critical to as primary producers in oceanic gyres, as agents of biological nitrogen fixation, and, in modified form, as the of marine algae.

Cacti perform photosynthesis in the same place as all other ..

Also, the difference in light intensity between a quarter inch from the tube and say two inches at the bottom of the plant will be huge, resulting in poor growth.

C3 photosynthesis – The most widespread type of photosynthesis ..

began the research of the process in the mid-17th century when he carefully measured the of the soil used by a plant and the mass of the plant as it grew. After noticing that the soil mass changed very little, he hypothesized that the mass of the growing plant must come from the water, the only substance he added to the potted plant. His hypothesis was partially accurate — much of the gained mass also comes from carbon dioxide as well as water. However, this was a signaling point to the idea that the bulk of a plant's comes from the inputs of photosynthesis, not the soil itself.