Fractionation of carbon isotopes in oxygenic photosynthesis the bundle sheath cells. This limits the carbon available to RuBisCO, which in turn lowers its fractionation effect. This accounts for the overall delta value in C4 plants to be -12 to -16 ‰. Plants that use Crassulacean acid metabolism, also known as CAM photosynthesis, temporally separate their chemical reactions between day and night. This strategy modulates stomatal conductance to increase water-use efficiency, so is well-adapted for arid climates. During the night, CAM plants open stomata to allow CO to enter the cell and undergo fixation into organic acids that are stored in vacuoles. This carbon is released to the
Ghetto Day/What I Need Picnic'." This sampling was also praised by Fred DeUar of "High Fidelity News and Record Review", who stated it was done "in the cause of better-class '90s pop." "Billboard" called the track "a languid, liquid sketch of a lazy city afternoon" and stated "it gets the nod as [the album's] likeliest knockout contender." Ron Wynn from AllMusic declared "What I Need" one of the album's best. "Billboard" Larry Flick labelled it a "floor-filler" and an "upbeat rouser." Another reviewer from the same publication thought "What I Need" was one of the hits to be had from "Storyteller". "Vibe" magazine stated