Category Archives: Cold hardiness

Keeping busy until spring

The idea of a plant being able to conduct photosynthesis during freezing temperatures was a novel idea to me. The researchers in this article wanted to see how lingonberries were able to recover to a photosynthetic state during periods of mild temperature during winter months. They tested temperature, photoperiod, and preceding frost for effects on the lingonberry, and what they discovered surprised me. Extreme cold slowed down the recovery, however the berries were able to come back and maintain photosynthesis even at freezing temperatures. These berries amaze me! The more I learn, the more I realize I don’t know. Check out their findings in the article listed below. CM Fairbanks
Saarinen, T., R. Lundell, and H. Hänninen. 2011. Recovery of photosynthetic capacity in Vaccinium vitis-idaea during mild spells in winter. Plant Ecol 212:1429-1440

Frozen berries are sweeter?

It is said that Alaskan berries are said to be sweeter after they freeze. Is this true? I am having a hard time finding any hard evidence to prove as to why this might be, but many articles talk about how this seems to be true, with out a scientific reason. I imagine it must have to do with the crystallization of the sugars in the berry. One article references another article to say that the frosting of brussel sprouts causes an increase in sugars in the cell. BE Fairbanks

Anonymous, 2007. Berry Crazy. Available online:  Berries

Hardiness stages of blueberries

This link with nice photos of different growth stages of a blueberry plant.   What I find interesting is the different cold tolerances of the different stages, which as mentioned in this class, is an important consideration when predicting fruit production from our plants.  For example, flower bud swell can tolerate 10-15F, while flower bud break is tolerant to about 20F, full bloom to 28F and petal fall (while fruit is developing) only 32F.  This shows how vulnerable late developmental stages can be and how a cold snap late in the season could be detrimental to the fruit crop.

Note that this site talks about highbush blueberries and not our native bog blueberry, Vaccinium uliginosum, in Interior Alaska.  I need to do more searching to find the critical temperatures for V. uliginosum! However, I think that these photos of bud stages and listed critical temps are helpful reminders that not all stages or parts of a plant have the same temperature tolerances.  The plant is growing, developing and changing and as managers, one would need to be attentive to these changes.

Blueberry hardiness