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Scientists to study night behaviour of the lettuce By Roger Highfield Science Editor

A TEAM of scientists is to camp overnight in a lettuce field as part of an experiment to extend the shelf life of salads.

In a previous study, the shelf life of basil was increased by 170 per cent by harvesting at 6pm and not 6am. Now the scientists, from the University of Southampton, hope to find the best time of day to harvest salad crops. Vitacress Salads, of Hampshire, is funding a three-year research project to improve the ability of leaves to withstand washing and packing.

During the experiment early in July, a team from the university's School of Biological Sciences will camp on a Vitacress Farm near Alresford, Winchester. Over 24 hours, they will harvest a sample of baby leaf lollo rosso and roquette every four hours. The leaves will be bagged and sent in a refrigerated vehicle to the university for analysis. The experiment is to be replicated with other crops such as spinach, cos and basil.

Dr Gail Taylor, leader of the plants and environment laboratory, said: "This experiment is to see whether time of day makes any difference. There is some evidence that if you harvest salad at night, it is of a better quality and will last longer in the supermarket. During the day, photosynthesis ensures a build-up of sugars which appear to be important in producing a good quality leaf. Other changes also occur between day and night, including reduced water loss in the evening as stomata in the leaves close. We are only just beginning to unravel how these changes might affect salad quality."

-- Anonymous, June 27, 2001

Answers

Gee, I always thought you were supposed to harvest early morning.

-- Anonymous, June 28, 2001

Me too. I wonder if the same applies to flowers?

-- Anonymous, June 28, 2001