What’s the best way to deal with stress?
The most effective strategy might be to avoid it completely, says plant researcher Karen Tanino.
“My research approach is to look at avoidance mechanisms,” said Tanino, a plant physiologist at the University of Saskatchewan who studies abiotic stress factors in agricultural crops.
“We have a lot of stresses in the summer, like heat stress in mid-summer causing floral abortion in canola, for example.
“If we can encourage and help a plant get off to an earlier start — a more vigorous start — it simply shifts the whole reproduction process earlier … so rather than trying to enhance the tolerance to heat, it’s more about looking at how can we speed up the plant development in order to avoid heat stress and allow the plant to capture more of the moisture that’s available in the spring.”
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Tanino’s work at the U of S is aimed at helping plants avoid common and costly abiotic stresses such as heat.
To that end, Tanino and a pair of collaborators at the U of S have a novel seed treatment under patent protection that hastens germination under low temperature conditions and improves lateral root development in the plant’s early growth stages.
In research trials, the seed treatment has proven effective on a number of crop types and cultivars, including species that are notorious for slow or inconsistent germination.
When applied as a liquid treatment before planting, the seed treatment enhances vigour and gives crops a strong, early and uniform start.
“Improving the seed package is a very simple, low cost and … effective way” to minimize stress through avoidance, Tanino said.
“Cicer milkvetch, for example, is notoriously difficult to germinate but under the seed treatment, it seems to increase total germination, uniformity of germination and lateral root growth.”
Tanino’s research on frost damage takes a similar tack.
In other words, frost avoidance is the underlying theme.
For example, Tanino, researcher Brian Fowler and a graduate student are examining the physiological mechanisms that prevent frost damage in winter wheat and fall rye.
Relative to winter wheat, winter rye confers a greater level of freezing resistance, suggesting that the physical attributes of the winter rye crown may be more adept at preventing the entry of frost crystals into critical tissues of the crown itself.
“We all know that the winter wheat crown is the most critical organ for overwintering, but the crown itself is very complex,” Tanino said.
“So in order to really advance the low temperature stress resistance of winter wheat, I think we really need to understand the mechanisms of injury within the crown (and the) physiological barriers that prevent that ice from getting into the critical tissues.
“Understanding those mechanisms is also a strategy based on avoidance.”
In another project, Tanino and others have been using the Canadian Light Source synchrotron to examine the cuticular layers of leaves taken from wheat, soybean, corn and canola plants.
Until recently, much of the plant research pertaining to drought avoidance has focused on the stomata, the tiny openings or pores found on the epidermal layer of plant leaves or stems.
The stomata facilitate the exchange of gases. Depending on carbon dioxide, temperature and moisture level, they will open or close to regulate plant performance and manage moisture loss.
Rather than focusing on stomatal function, Tanino’s research looks at leaf hydrophobicity, or the ability of the leaf’s cuticular layer to both avoid water loss from the plant and repel water from the surface.
“In order for ice to form, water has to be able to be able to stick. If it just rolls off, there’s no way it’s going to freeze,” Tanino said.
“So the hydrophobicity of the cuticle layer will influence frost formation as well as help to avoid water loss from the plant at the same time.”
Tanino and her research colleagues are using the synchrotron to assess the variation in the composition, thickness and volume of the cuticular layer and analyze its ability in different crop types and cultivars.
