Billion year upgrade via UV?

Ultraviolet light exposure could kick-start the photosynthetic machinery in seedlings.

Senior lecturer at the Institute of Natural Resources Dr Jason Wargent, has found exposing lettuce crops to ultraviolet (UV) light in the early stages of growth leads to increased photosynthetic activity and increased yield.

His United Kingdom-based research team took two sets of lettuce seedlings and exposed one to UV-B light while still seedlings.

“Many crops are quite heavily protected from the sun when they are very young, via the use of poly-tunnels or glasshouses, but in this study we allowed the lettuce crops to be exposed to UV light earlier,” Wargent says. “Usually they are grown indoors until they are a youngish age then they get moved outside. In this study we put the plants into poly-tunnels which were covered in a film that allowed the UV light through.”

At harvest, the plants that had the early UV exposure were bigger.

“We examined photosynthetic capability in the plants, and our study shows the plants that were being exposed to UV had higher photosynthetic rates, and also seemed to be more robust against high temperature and light stress,” he says.

“What we think is happening is that the early period of exposure allows a plant to, in effect, build up a tolerance to UV so that when they get moved outside, they’re able to withstand sunlight better.”

Many crops in New Zealand are grown outdoors, and Wargent says if they were better prepared to make that transition, yields could increase.

“This has ramifications for most of the vegetable and some other crops grown in New Zealand, not just lettuces.”

Wargent says further research is being carried out to see what the New Zealand levels of UV can really do in terms of the potential to manipulate crop quality.