Answer:
Please look in the explanation section.
Step-by-step explanation:
Plants are characterized by absorbing nutrients in the soil through a process known as active absorption, which requires a certain amount of energy expenditure. Nitrogen, phosphorus, among other absorbed nutrients are carried to younger leaves, before the older leaves fall off. This is done by plants for later use. This process of bringing those nutrients to the younger leaves implies energy savings. The plant in question contains high mineral ions that are not removed from the senescence leaves before the leaves fall. Normally, when plants absorb nutrients again they turn yellow, this means a breakdown of chlorophyll, as nitrogen and magnesium are removed, but this process does not occur in buckthorn.