Fractionation of carbon isotopes in oxygenic photosynthesis product 3-phosphoglycerate is depleted in C due to the kinetic isotope effect of the above reaction. The overall C fractionation for C3 photosynthesis ranges between -20 to -37‰. The wide range of variation in delta values expressed in C3 plants is modulated by the stomatal conductance, or the rate of CO entering, or water vapor exiting, the small pores in the epidermis of a leaf. The δC of C3 plants depends on the relationship between stomatal conductance and photosynthetic rate, which is a good proxy of water use efficiency in the leaf. C3 plants with high water-use efficiency tend to
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