Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A flower has ovules, and each one is to be fertilised. In each ovule, one male gamete fuses with the egg and one fuses with the two polar nuclei. Each pollen tube enters one ovule and releases two male gametes.
Outbreeding devices are different timing, different positions, self-incompatibility and unisexual flowers. A pollen tube grows through the style, enters the ovule by the micropyle and enters a synergid. Each tube delivers two male gametes. Time is the distance divided by the rate.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. ovules. male gametes for each ovule. male gametes for each tube.
Plan. Count the gametes, then divide by the load of a tube.
Step 1. The gametes. male gametes.
Step 2. The tubes. tubes.
Answer: male gametes; tubes.
Check. One tube for each ovule gives tubes.
Watch out. At least one pollen grain is needed for each ovule, which is not the same as one grain for the whole flower.
Log in to join the discussion.
Loading…