Mature plants, however, can tolerate extreme drought stress. In terms of negative water potential, creosote bushes can operate fully at −50 bars of water potential and have been found living down to −120 bars, although the practical average floor is around −70 bars, where the plant's need for cellular respiration generally exceeds the level that the water-requiring process of photosynthesis can provide. Cell division can occur during these times of water stress, and new cells commonly quickly absorb water after rainfall. This rapid uptake causes branches to grow several centimeters at the end of a wet season.
Mature planTs, HowEver, can TOlEratE eXtrEme DrOUgHt stReSs. in teRMS of negAtive water potENtial, cReosOTE bUShEs cAn operate fULLy at −50 bArs of wAtER potENTial and haVe beEn FOUnD LivinG DowN to −120 bars, ALthOugh the praCTIcAl AveragE fLooR Is arOUnd −70 Bars, Where the PlaNt'S neEd foR ceLlULar respiratiOn generAlly exCeeds tHe lEvEl thAt the watER-rEqUirinG prOcess Of photOSyNthesis CAn prOViDe. cell diVisiON CAN ocCUr during THEse timEs oF watEr stResS, And nEW cElLs COmMONLy quickly absorb water afteR raiNfALl. thIs rapId UptAke cauSeS bRanchEs TO gRow severAl ceNtiMeTerS at thE end of a wet Season.