ARECENT survey has discovered a few more interesting facts about fragrance. It was noticed that in stores which perfume the air, shoppers spend longer looking at the merchandise. And, certainly, part of the success of the Body Shop must be the almost edible smells which reach out and beckon people inside. Just as aromatherapy oils are used to treat ailments from depression to insomnia, so it was discovered that whiffs of peppermint and lily of the valley improved the alertness of people engaged in monotonous tasks. Similarly, the citrus tang of lemons and oranges, when pumped through the air-conditioning system of one office, increased productivity. While it is something which you may have always suspected, the study also showed that pleasant, summery, fruity aromas of flowers, fruit and food can relieve depression in hospitals, even when the patients are not aware of the scents. And - we all know this one to be true - we have an enhanced self-image and greater confidence when we know those around us like the perfume we are wearing. Perhaps not so surprisingly, scientists have long-known that perfume and other smells can do more than create a sense of well-being. They can actually produce a physical response. Apple-nutmeg odours can reduce blood pressure. And brain wave patterns have revealed that jasmine is a stimulant; lavender a relaxant. Likewise, the smell of peppermint or rosemary is energising, rose is calming, sandalwood is sensual. At the International Flavours and Fragrances, one of the world's major perfumers, researchers are working on a study related to mood. According to vice-president Mr John Reznor, the results will help perfumers create more than just a pleasant scent. ''If one can combine the positive notes into a fine fragrance, then the pleasurable effect of a well-crafted perfume can make an even greater impact,'' Mr Reznor said. Certainly, a gift of fragrance or the increasingly popular essential oils will have a great impact on any mother on Mother's Day.