how do plants move nutrients from the roots?

The plant has memory for every specific moment of the cultivation, in a balanced substrate that contains minerals, organic matter, and microorganisms, the exchange of immobile nutrients (minerals) takes place day and night if there are microorganisms to dissolve those minerals. The plant knows what it needs, when, how much, and where it needs it, and it searches for it in the substrate. For example, I use substrates where I include organic matter rich in slow-release nitrogen; during flowering, the nitrogen is still there, but the plant will only take what it needs. Another thing is feeding the plants only with highly soluble fertilizers focused mainly on N P K C and Mg; this way, it's easy to cause imbalances at any stage of cultivation, which can in turn cause imbalances in immobile nutrients. As I say, I focus on the substrate and microbiology; I try to get closer to the natural process of the forest, I don't force the cultivation times, just like a good meal has to be made slowly. The transport of any nutrient through the plant is facilitated by adding carbohydrates; I use molasses and honey throughout the cultivation, this way I facilitate the energy (light) conversion into sugars and in turn provide food for the microorganisms to dissolve minerals and organic matter more quickly. The influence of the moon on the waters is very interesting to understand nutrient absorption and water movements in each lunar phase. Lastly, water, the indispensable element, the vehicle for everything; for me, the type of water is fundamental, my favorite is rainwater or mountain water. I know fantastic mineral waters for humans that are fatal for cultivation due to the mineral load or high pH, which can block the absorption of many basic nutrients, etc. Additionally, to facilitate nutrient absorption and water flow through the plant, I always structure it before adding the nutrients. In short, to achieve a balance between immobile and mobile nutrients, my advice is to have a substrate rich in minerals, organic matter, and microbiology, which takes care of making micro and macronutrients available during cultivation. This way, I only have to focus on the soluble application of organic N P K C and Mg depending on the appearance of the plant related to these nutrients. Have you traveled through a root to the plant? Have you become chlorophyll? Do the exercise. It's fantastic!! Cannabis helps for the journey. Cheers!!