What symptom is indicative of phosphorus deficiencies in young plants that have been exposed to good growing conditions after cool, wet weather?

Phosphorus deficiencies in young plants are often characterized by a distinctive purpling of the leaves, especially noticeable on the leaf tips and edges. This coloration arises because phosphorus plays a critical role in the production of energy molecules such as ATP (adenosine triphosphate) and is essential for plant growth and development. Under good growing conditions after cool, wet weather, if phosphorus is lacking, the plant is unable to synthesize the necessary compounds effectively, leading to a build-up of anthocyanin pigments, which displays as purple leaf tips. This symptom is particularly apparent in young plants, as their smaller size and developing tissues make them more susceptible to nutrient deficiencies. Other options, such as yellow or pale green leaf tips, can indicate different nutrient deficiencies or stress but are not specific indicators of phosphorus deficiency.