Quick Dips

Shopping for Daylight

Technology designed to help create the perfect shopping mall experience is being used at the National Climate Laboratory by scientists studying the effects of light on crops. Controllable lighting and a custom-made system of blinds means that technician Harry Wiggins can re-create sunrise, high noon and dusk in two of the lab's 24 controlled environment rooms.

Until now computer-controlled systems have been able to reproduce conditions from subantarctic to tropical, but simulated daytime, with all its fluctuations of intensity and cloud cover, has been impossible. Lights have either been on or off, with total day length supplied in timed "blocks" of constant light.

The $10,000-a-room system was developed from technology used in shopping malls in Australia, where the lights brighten or dim according to the weather outside, ensuring a constant, perfectly lit environment inside for consumers.

Blinds are needed in the Climate Lab rooms as the lights take about 15 minutes to warm up to full brilliance and another 15 minutes to become fully controllable. Some plants would object to such a wake-up call, and the experiment would be compromised, so the blinds draw automatically when the lights are programmed on.

It's not just a question of low light levels at either end of the day -- there's also more red light available then, and Wiggins simulates this with tungsten bulbs which automatically adjust as the day wears on.

The Climate Lab is unique in the Southern Hemisphere and is used by HortResearch, other CRIs, universities, overseas scientists and commercial companies. Temperature, carbon dioxide, day length, light intensity and spectrum and plant nutrition can all be precisely regulated and these factors can be altered individually so that researchers can see how each one is affecting a crop.

The lab has been put to more off-beat use with contracts to test storage of newsprint reels, cheese wrapping and even as pre-Commonwealth Games acclimatisation training for the Silver Ferns. [Steamed up for Kuala Lumpur, August]