I have been wondering about this: What effect does temperature have on the viability of seeds? Does it affect all seeds the same? If seeds from tripocal species are subjected to freezing temperatures, do they die? I'm sure this varies from species to species, but I've been hesitant to order seeds to be shipped in winter, for fear that they would die in the mail, since it is so cold here. I have on order some seeds of species native to northen Australia (from cultivated stock in Canada). Should I wait until spring to have them shipped, or would they be okay in this cold? I know that some seed banks store seeds at super cold temperatures, but is this the same cold as what we have here in Manitoba? Btw, I'm not sure if this is the right place to post this, but I couldn't find a more appropriate place, since the General Gardening and Question and Answer forum is closed to me now.
Viability Utility (re: Seed Viability Equation) and Seed Viability References There is a lot of literature being produced on this topic at the moment, due to the urgent need for preserving biodiversity via seed banks. Have a look at page 23 of this guide: A Protocol to Determine Seed Storage Behaviour (PDF) to see optimal temperatures for a range of tropical species (ranges from 1° Celsius to 15° C). The short answer to your question is that most tropical plants will produce recalcitrant seeds and hence will die if exposed to freezing temperatures.
I saw that, but it seemed way too complicated for what I wanted. That's what I was looking for. Thanks. Although, in the link you give, it does not seem to indicate that most tropical seeds are like that, only a few. I guess it's better to be safe than sorry. So, do not ship tropical seeds in winter.
Fair enough, it is difficult to find percentages. Here are a few references: Forest Genetic Resources #28 from FAO: Handbook of Seed Physiology (2004): Key words here are "probably many" in reference to nonorthodox seeds in tropical / subtropicals and "almost all knowledge amassed to date about seed biology...representing less than 0.1 percent of the higher plants" And, if the seeds you are ordering are from the dry tropical forests: Ecology of seed and seedling growth for conservation and restoration of tropical dry forest: a review (think, for example, of the acacias of tropical dry Africa)
