Why do flowers produce sugary nectars or nutritious pollen?
They do this to attract pollinators.
Plants that do not disperse their pollen through wind must attract animals that will collect pollen from the anthers on the stigma of the flower on their bodies while they feed on or collect the pollen or nectar. As they move from flower to flower, they carry the pollen from flower to flower. The pollen contains the sperm of the flower, and when it lands on the pistil on a flower, the sperm will undergo a process that ends with fertilization of the ovum in the ovule or ovules within the ovary of the flower.