The event that will happen first if a plant does not have enough water is a decrease in the rate of the Calvin cycle.
When a plant is under stress and not getting enough water or nutrients the plants first response is usually a reduction in stomatal conductance to prevent excessive water loss through transpiration.
The Calvin cycle in plants is a process that plants and algae use to turn carbon dioxide from the air into sugar, the food autotrophs need to grow.
Every living thing on Earth including humans depends on the Calvin cycle.
Plants depend on the Calvin cycle for energy and food.
In plants, carbon dioxide enters the interior of a leaf via pores called stomata and diffuses into the stroma of the chloroplast—the site of the Calvin cycle reactions, where sugar is synthesized.
These reactions are also called the light-independent reactions because they are not directly driven by light.
The oxygen in the CO2 ends up as water but that is very hard to see in textbook versions of the Calvin Cycle because water is both used and produced in its various steps even though in the end it is a net product like glucose.
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers.
It is a passive process that requires no energy expense by the plant.
Plants can alter the size of their boundary layers around leaves through a variety of structural features.
Leaves that possess many hairs or pubescence will have larger boundary layers; the hairs serve as mini-wind breaks by increasing the layer of still air around the leaf surface and slowing transpiration rates.
Transpiration is important for plants as it helps in the conduction of water and minerals to different parts of the plants.
Due to the continuous elimination of water from the plant body, there is a balance of water maintained within the plant.
It maintains osmosis and keeps the cells rigid.