are 7 days alot?
1 day is too short?
when should i start to worry that stratification might affect my results?
what are best conditions of cold stratification: distilled water/agar/plates/soil/dry seeds?
Hi Radwa,
1. There is a guild-line on stratification in this attached article, which is from ABRC (Arabidopsis Biological Resource Center) [ https://abrc.osu.edu/seed-handling ] (see attachment).
2. See page 2, point #13 (yellow highlight).
3. Depend on your research approach, (1) for tissue-culture, you can place seeds on agar in a plate, and as the article suggests-- Place the plates at 4°C for 3 days. (2) if soil-growing is needed, we just plant seeds in the soil in a container, cover the container with a layer of Saran-wrap (or plastic wrap, see attached pic), then place the contain in a 4oC cooler in our greenhouse for 3 days (our greenhouse equips with a 4oC cooler for Arabidopsis research).
4. As the article points out: "Cold treatment of dry seeds is usually not effective in breaking dormancy. "
Hi Yuan,
Thanks alot for your answer. i did pass by this protocol but it only says 7 days is for newly harvested seeds to breake dormancy. how about 1 year ols seeds for example?
I know also it might fasten the flowering and so, but again what is considered too much!
I might try the saran-wrap once, we use plastic clear lids..
Thanks
Hi Radwa,
1. If you have clear plastic lids, use them. We used them when we had them. I forgot to mention, we wet the soil with fertilizer solution (with water) before planting seeds.
2. I don't know how much time is considered 'too much'. However, if the 'incubation time' is able to synchronize seed germination, then I would consider the 'duration' of time is good enough. No need to let them sit in wet soil too long, and waste your time.
3. If the seed is properly stored (such as proper temperature and humidity, as also mentioned in the article), I think that 1 year (or even longer) of storage the seed are still viable for experiment. Stratification of seed can use the same protocol.
Normally 2-4 days of cold treatment (seed should be wet) is sufficient. Some mutants, seeds that have been stored long (>2 years) or seeds of poor quality could benefit from longer period. If 7 days of cold treatment is not sufficient, you might need to add GA to break dormancy.
Concerning 'too long'. I used to store the sterilised seeds in water/agarose in the fridge (wrapped in alufoil) for up to 3 weeks. Seed start to germinate in these conditions after about 2 weeks, but these can still be handled for sowing.
Thanks alot Eric,
I never knew Arabidopsis can stay in cold for 3 weeks!
I did seed vernalization of Arabidpsis for six weeks. Some of them germinate in dark.
An answer above suggested that the seed should be wet . A point of clearification , seed should be imbibed with water but then allowed to dry off a bit so that they are not wet but moist , too much moisture as in being saturated wet will lead to problems , soak seeds for 24 hrs , the drain immediately and allow to displace excess moisture in paper towels . After a 24 hr drying period it will be safe to put into a stratification situation ,making sure that they stay moist . Too much moisture will decrease the amount of time that they can stay refridgerated and might lead to rotting instead of germinating . Since it takes so few days to stratify I am a bit confused as to why enter into a stratification process until necessary , seems like pushing the length of time in stratification will lead to problems . Moist cold is an ideal environment for certain cold tolerant fungi that can get into the process , the longer the term , the more likely the chance of fungal problems.
Thanks Young, yes I think this happened once when I actually forgot the tube with wet seeds in cold room!!
William, am not going for longer times I am just asking for the longest that is still in the normal limits. I found the germination more synchronized after 5 days cold treatment and that's why. Thanks for the information, the seeds are sterilized and ideally should not pick any infection, but I think it's better not to leave them alot in cold and wet like you say.
I stratify a number of species of seeds and yes you are right that there is a peak and then it plateaus off from there , its a good question perhaps the divergence of various forms of English makes it a bit harder to understand fully . Nevertheless , once the peak has been met there is no need to go further , although if cold enough you can cheat for a bit of time without harm . I tend to want to stratify seed in moist perlite which has been drained for a day or so , again the objective is moist but not wet , perlite is generally sterile and can be easily sterilized with boiling water , try to avoid chemicals as they might linger and alter germination. I hope that our observations have been of help to you .
For germination studies of my Arabidopsis mutants I used 2-3 days of cold stratification at 4 degrees Celsius. To my knowledge new seeds need longer but for 1 year or older seeds I always used 2 days. 7 days seems way too long. In general I wouldn't leave them for more than 3 or 4 days. The medium will of course depend on the purpose of the experiment. But its important to keep them moist during stratification to help break dormancy.
if you want to by pass stratification one method is to soak seed for 24hr in 5000 ppm KNO3 . Drain and wash after the time is up and plant , many seed will germinate quickly to Potassium nitrate treatment
Hi William, do you have a reference for this that I can quote? Could be v useful for a grant application. And how soon can they germinate after the 24 hours in KNO3? Many thanks!!!
- Badges
- Science topic
- Similar topics
- Agriculture
- Horticulture
- Seeds