Fractionation of carbon isotopes in oxygenic photosynthesis Calvin cycle during the day, when stomata are closed to prevent water loss, and the light reactions can drive the necessary ATP and NADPH production. This pathway differs from C4 photosynthesis because CAM plants separate carbon by storing fixed CO in vesicles at night, then transporting it for use during the day. Thus, CAM plants temporally concentrate CO to improve Rubsico efficiency, whereas C4 plants spatially concentrate CO in bundle sheath cells. The distribution of plants which use CAM photosynthesis includes epiphytes (e.g., orchids, bromeliads) and xerophytes (e.g., succulents, cacti). In Crassulacean acid metabolism, isotopic fractionation combines the effects of
What I Need What I Need "What I Need" is a song by American recording artist Ray J. It was written by Rodney "Darkchild" Jerkins, LaShawn Daniels, Fred Jerkins III, and Ray J for his 2005 album "Raydiation", while production was handled by the former. Released as the second single from the album following "One Wish", it reached number 58 on "Billboard"s Hot R&B/Hip-Hop Songs chart. "What I Need" earned generally positive reviews by critics. "Billboard" magazine felt that the song "should be enough to momentum. Here, Ray J's vocals once again seem strained as he cops another plea to the woman he