could lead to the development of plants with improved avoidance or slowing of desiccation and better water use efficiency. ABA is the trigger for the closure of the stomatal opening. To trigger this it activates the release of anions and potassium ions. This influx in anions causes a depolarization of the plasma membrane. This depolarization triggers potassium plus ions in the cell to leave the cell due to the unbalance in the membrane potential. This sudden change in ion concentrations causes the guard cell to shrink which causes the stomata to close which in turn decreases the amount of water lost. All this is a chain reaction according to his research. The increase in ABA causes there to be an increase in calcium ion concentration. Although at first, they thought it was a coincidence they later discovered that this calcium increase is important. They found Ca2+ ions are involved in anion channel activation, which allows for anions to flow into the guard cell. They also are involved in prohibiting proton ATPase from correcting and stopping the membrane from being depolarized. To support their hypothesis that calcium was responsible for all these changes in the cell they did an experiment where they used proteins that inhibited the calcium ions for being produced. If their assumption that calcium is important in these processes they'd see that with the inhibitors they'd see less of the following things. Their assumption was correct and when the inhibitors were used they saw that the proton ATPase worked better to balance the depolarization. They also found that the flow of anions into the guard cells were not as strong. This is important for getting ions to flow into the guard cell. These two things are crucial in causing the stomatal opening to close preventing water loss for the plant. Ion uptake and release Ion uptake into guard cells causes stomatal opening: The opening of gas exchange pores requires the uptake of potassium ions into guard cells. Potassium channels and pumps have been identified and shown to function in the uptake of ions and opening of stomatal apertures. Ion release from guard cells causes stomatal pore closing: Other ion channels have been identified that mediate release of ions from guard cells, which results in osmotic water efflux from guard cells due to osmosis, shrinking of the guard cells, and closing of stomatal pores (Figures 1 and 2). Specialized