WillysWoodPile

How can a plant that has water flowing through it survive [below] freezing temperatures.... on a consistent basis? Or are we talking one night of freezing temperature?
I mean, I also had my Brad's Black Heart plant survive 2 nights of 28-32 degree temperatures [with barely the edge of two leaves burned] but I think conditions were just right, like there being certain levels of humidity or no humidity or something like that. It died on the third night of 26 degree freezing temperature.
I could understand if the plant produced a natural anti-freeze but just water flowing through it's "veins"? It does not seem possible in my mind that it would ever "adapt" to consistent freezing temperatures.
Are you just looking for that plant that will withstand a "few" nights of unpredictable freezing weather in otherwise "normal" weather so you don't have to mad-rush to cover your plants?
I am looking at this from a simple perspective....and that is that water freezes at 32 degrees Fahrenheit. The only way I see it not freezing is either insulation or the plant producing a type of antifreeze [that is if the plant even had that type of information in it's genes].
-- But like Fred says, It does sound fascinating and I would be interested in seed too since I live in lower Michigan. A plant like that would easily give me another month.
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Temperature
The degree of hotness or coldness of a substance is called temperature (Eagleman 1985). It is commonly expressed in degree Celsius or centigrade (C) and degree Fahrenheit (F) . This climatic factor influences all plant growth processes such as photosynthesis, respiration, transpiration, breaking of seed dormancy, seed germination, protein synthesis, and translocation. At high temperatures the translocation of photosynthate is faster so that plants tend to mature earlier.
In general, plants survive within a temperature range of 0 to 50 C (Poincelot 1980). Enzyme activity and the rate of most chemical reactions generally increase with rise in temperature. Up to a certain point, there is doubling of enzymatic reaction with every 10 C temperature increase (Mader 1993). But at excessively high temperatures, denaturation of enzymes and other proteins occur.
Excessively low temperatures can also cause limiting effects on plant growth and development. For example, water absorption is inhibited when the soil temperature is low because water is more viscuous at low temperatures and less mobile, and the protoplasm is less permeable. At temperatures below the freezing point of water, there is change in the form of water from liquid to solid. The expansion of water as it solidifies in living cells causes the rupture of the cell walls (Devlin 1975).
The favorable or optimal day and night temperature range for plant growth and maximum yields varies among crop species.
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Relative Humidity
The amount of water vapor that the air can hold depends on its temperature; warm air has the capacity to hold more water vapor than cold air. According to Eagleman (1985), there is almost one-half reduction in the amount of water vapor that the air can hold for every 10 C drop in temperature.
Relative humidity (RH) is the amount of water vapor in the air, expressed as the proportion (in percent) of the maximum amount of water vapor it can hold at certain temperature. For example, an air having a relative humidity of 60% at 27 C temperature means that every kilogram of the air contains 60% of the maximum amount of water that it can hold at that temperature (Miller 2001).
The amount of water vapor in the air ranges from 0.01% by volume at the frigid poles to 5% in the humid tropics. Compared to dry air, moist air has a higher relative humidity with relatively large amounts of water vapor per unit volume of air.
The relative humidity affects the opening and closing of the stomata which regulates loss of water from the plant through transpiration as well as photosynthesis.....
--For the full article: http://www.cropsreview.com/climatic-factors.html