In order for an ovule (egg cell) in a flower to be fertilised and form a viable seed, pollination must occur. In this process, a sperm cell is delivered to the ovule when the pollen grain lands on the stigma and grows a tube, which enters the ovary and discharges the sperm cell to form a diploid zygote when it fuses with the egg cell. Although it only takes one pollen grain to successfully deliver sperm to the egg, numerous pollen grains are generally transferred to the stigma during insect pollination of flowering plants. Which phenotypic traits of pollen would you predict to be selected upon to promote survival and fitness within an insect-pollinated flowering plant?

Question

Quizplus · Accepted Answer

High pollen tube growth rate and ability to detect chemicals from cells surrounding the egg are advantageous traits for successful pollination. Faster tube growth allows the pollen to reach the ovary more quickly, increasing the chances of successful fertilization. The ability to detect the chemical signals from cells surrounding the egg allows the pollen tube to navigate more effectively towards the egg. This is particularly important in plants with complex floral structures or long style lengths. While the other traits listed may also be advantageous, they are not as directly related to successful pollination.

In Order for an Ovule (Egg Cell) in a Flower