Zooming in on pollen

Press, 11 October 1986, Page 20

Zooming in on pollen

... for the good of hay fever victims

No one can escape from thetn. Pollen grains surround us most of the time.

These tiny particles are in the air we breathe, the honey we eat, in roadside rain puddles, even high up in Southern Alps snow.

Millions of people are allergic to pollen. Radio stations in some countries even broadcast pollen warnings so these people can stay inside.

Dr Neville Moar of the D.S.I.R.’s Botany Division at Lincoln has devoted his working life — some 40 years — to studying pollen. Hay fever sufferers have found his expertise very helpful. He can recognise hundreds of pollen grains with the help of high-powered microscopes. There is a range of shapes, sizes, and wall patterns which help distinguish one pollen type from another. Tiny holes in the pollen grain walls allow the grain to swell. Pollen tubes also grow out of these holes at germination. Plants produce pollen in vast quantities, especially in spring. The pollen grains float in the air until they finally settle — and that can be all the way from Australia across the Tasman Sea to New Zealand.

Casuarina pollen has even been found high up in Southern Alps snow, while pollen from New Zealand has been found in the sub-Antarctic Islands.

According to Dr Moar, pollen grains may be preserved in various sediments such as peats, lignites, or coal for millions of years. For example, pollen grains are found in sediments of the Cretaceous Period which began about 140 million years ago. This makes pollen grains especially important in oil exploration as they are preserved best in precisely the same environments' where oil and coal later formed.

Dr Moar is also using pollen analysis to help honey exporters sell honey overseas. From his analysis, he can tell which flowers the bees have obtained nectar from and, sometimes, even the actual area. Goats rue pollen, for example, is found only in honey from the Manawatu district, because this is the only district in which the weed is established.

Now he is working on a pollen atlas of New Zealand native plants, which he hopes to complete by the time he retires next year.