Quirks & Quarks

Can we make veggies winter hardy like daffodil plants?

Different plant species have different tolerances to cold due to many years of acclimation to different temperature environments.
Plants like tulips and daffodils are better able to withstand frost than plants like tomatoes or green peppers.

This week Quirks Question comes from Philip Lucas in Peterborough, Ont., who asks, "I've noticed in the spring, I can see the tulip leaves and the daffodil leaves pushing through the hard, frozen ground, but we can't plant or put other plants in like tomatoes or green pepper vegetables because they can't stand the frosty nights. Why is this? Can we cross a tulip or a daffodil with a vegetable like a tomatoe or green pepper to make a winter hardy vegetable?" 

Dr. Youbin Zheng, a professor of horticulture the University of Guelph's School of Environmental Science, says when temperatures drop, water in plant tissue can turn into ice.

When ice is formed inside of cells, the ice crystals can rupture the cell membrane and lead to cell death.

When ice is formed outside of the cells, it draws water out of the cells, dehydrating them, which can injure the plant tissue.

Different plant species have different tolerances to cold due to many years acclimation to different temperature environments.

There are different mechanisms involved in cold tolerance. For example, a plant can accumulate solutes, like sugars, which lowers the plant cells freezing point.

Another way a plant can develop cold tolerance is that certain proteins can stabilize the cell membranes to increase its resistance to rupture.

Dr. Zheng says there are cold tolerant genes, so it is possible to create cold tolerant tomato or green pepper using modern biotechnologies such as genetic engineering.

However, it may not possible by simply cross a tulip with a tomato to create a cold tolerant-tomato due to the fact that tulip and tomato are very different species.