Jade Bell, of Kaiapoi High School, asks :-

Is pollen always yellow?

Neville Moar, a pollen expert with Landcare Research NZ Ltd, Lincoln, responded.

Not all plants produce yellow pollen. Some produce orange pollen e.g. dandelion, others blue pollen, e.g. fuchsia, while some may produce pollen in various shades of red. However yellow in its various shades is the most frequent colour. The pigments which colour pollen are produced by complex organic chemicals which cover the surface and penetrate the wall of the pollen grain as it matures. The pigment role is not clear although it is possible that in some instances the colour may attract pollinating insects.

Beekeepers use the different colours of pollen collected by bees to identify both the pollen and nectar source worked. However, since different species can produce pollen of the same or similar colour it is wise to check the identity of the pollen under a microscope. Sometimes plants of the same species may produce pollen grains of more than one colour and sometimes sterile pollen can be recognised because of this. Sterile pollen grains may not produce pigments and then the pollen appears white. Kiwifruit is an example. It produces male and female flowers. The female flowers produce sterile pollen which is white in contrast to the deep cream of the fertile pollen of the male flowers.