According to my previous post I have written some logic behind root coil, pruning etc.
1. Roots are mainly two types Tap root and fibrous root. A tap root system has a main root that grows down vertically, from which many smaller lateral roots arise. Fibrous roots are thin and they do the absorption of mainly water and nutrients. Into the soil or potting media it grows in both directions in Vertically and Horizontally. During growing they produce more roots. When growing, elongating roots meet the walls of the container and cannot grow out or down further. The roots then grow along the sides of the pot creating a mass of intertwined or twisted roots. Fibrous root always grows to the presence of moisture. Into the pot main place is bottom of the container where we find massive roots due to presence of high moisture. After getting barrier they start twisting and make coils.
2. We should definitely prune roots because twisted coil roots cannot take up nutrients because plant take nutrient ions and nutrient ions move from outside to the inside of the root. Water diffuses into plants through their root hair cells. ions move from an area of high concentration (in the soil) to an area of lower concentration (in the root hair cell). When the concentration of roots is higher than media or soil then uptake of nutrient ions and water will become very poor. Lack of air space and the absence of air Nitrogen uptake will also become lower.
3. Root hair cells are partially permeable and mycorrhiza exchange food through this area. After pruning of fibrous roots we should wait until they repair their damages and generate new branches of root to get back the flow again. We should not apply mycorrhiza product just after pruning because they will suck energies from plants and let the plant die because without proper root structure plant will never been able to make sufficient energy. We should spray water 4 times for 10 days at least after pruning of route plant leaves release moisture by opening their stomata and root take up water to fulfill the absence of water. It is mandatory to place the pruned plant in a shaded are if possible.
4. The main three rootstocks are use in India is Rosa Multiflora, Rosa Indica and Rosa Edouard. Rosa Multiflora make massive twisted fibrous roots compare to other. Roots of Rosa Edouard and Indica mainly flows vertically and they are not as much vigorous compared to Multiflora.