Dear Martha,

I think, firstly, you sould determine pollen viability test. This article can contribute to you

http://www.plantstress.com/methods/1%20Pollen%20Firmage-Dafni%202001.pdf

I have not studied Conyza bonariensis before, but studied on a few fruits species pollens. It is important when you get pollens from the plant and how you get it.

Hi Martha,

Although I have not tried germinating pollen from sunflower family, i have done it in tobacco using 10% sucrose and 100 microgram/ ml of boric acid and kept at 25 degrees for few hours. You can try doing that also as mentioned in the previous discussion u can also check the viability of pollens by doing an FDA test.

Dear Mucahit, Thank you for your answer and the attachment too. This should actually be the first step before mixing the medium. Thanks!

Thanks Amita for your answer. The medium formula am using is almost similar to the one you used, except for a few modifications. I used 0.25% agar solution, 200 mg/L CaNo3, 100 mg/L Boric acid and 200 mg/L sucrose and kept it at 25 C also. Someone used this formula to grow pollen from blackgrass and the germination percentage was 85%!

There are numerous recipes for germinating pollen of various plants. For some plants a simple sucrose solution suffices (e.g. Asclepias), for others various micro-nutrients, such as Boron, Calcium, and others are needed. The old book by Stanley & Linskens has recipes in it, there is a book on Pollen Biotechnology (I think V. Sawney (spelling? I think there is a letter "h" in his name) is one of the editors, and a book edited by Mulcahey (I think) that may have some information. The book "Practical Pollination Biology" (edited by A. Dafni and others) also has some recipes. If memory serves, the artificial germination of 2-celled pollen is more difficult than for 3-celled pollen. I hope you are able to work out a suitable recipe for your Conyza pollen germination, but I do suggest, as someone else has mentioned, that you determine that the pollen grains take stains that indicate viability (Practical Pollination Biology lists several techniques). Best wishes, Peter

Thanks Peter!

Dear Martha, I haven't worked with sunflower but could suggest a thing or two based on my experience working with rice pollen. Germination could be very fast, within two minutes of anthesis and so is loss of viability (50% loss within 6-20mins). Hopefully sunflower doesn't have similar characteristics. But if it does, then you might want to consider reducing the time between anthesis and when pollen is dusted on the media.

Also, in place of agar, I used PEG 4000 and by varying the amount of Calcium nitrate tetrahydrate in my media, germination percentage varied considerably. I tried some other PEG, but no pollen germinated.

Room/laboratory/workplace temperature is also important. I confined my experiments to the laboratory with temperature around 22-26 C. I used to collect samples in the glasshouse (with temperature around 28 - 32 C) and take them to the laboratory for dusting unto my media. The high temperature of the glasshouse and time taken to get the pollen to a cool media in a laboratory all negatively affected my pollen germination. For some rice cultivars, >30 C is already supra-optimal for pollen development.

I hope you'll get the right recipe for you species very soon.

Best wishes,

Coast

I should say thanks to Peter for the reference materials. I will surely have a look.

Thanks Coast for your input. I got a recipe for sunflower pollen germination that I am going to try. I will also put in consideration the temperature effect on pollen germination.

You can try by adding stigma extract. It worked in sunflower

Hello Martha,

I am doing similar job of switchgrass pollen germination in my MS research. I use the similar medium and getting some germination. I had similar problem before, it was hard to see germinated pollen in the petri dishes. However, the problem is resolved now. For this i improved some activities like collected very fresh pollen, no water in medium petri dish, incubation in exactly 24 degree Celsius etc. Can you try once with this ideas ?

Hi Laxman,

Thanks for your input.

Which medium did you use?

See this link for entire prototypical: https://www.crops.org/publications/cs/pdfs/51/6/2698

Thanks Laxman for the link - quite an informative study.

We have tried using this medium (sucrose, agar, calcium nitrate and boric acid) but not at the concentrations used in the study. No pollen germinated. I think maybe this recipe works best for grasses? I noted that in the study, they kept the pollen at 24 C before germinating on medium - this is something am going to try. I keep the inflorescences at room temperature and allow them to germinate at 25-27 C and wait for an hour before checking.

Regards.

i have another related question pls..Can any one tell me why pollens of modern hybrid orchid varieties do not germinate on artificial media?. Pollens from native orchid varieties grow well on the artificial media.

Dear Martha,

all recomendations may help you, but consider the pH of your prepared media before adding Agar. my experience in the case of Prunus pollens says the best range is 4.5 to 5. try it. Good luck!

I would like to add that, as per our experience in sunflower, if you add stigmatic extract or crush the stigma in the PGM will give better results. In wheat instead of sucrose as a carbon source, maltose has given good results.

Dear Dr Coast,

I am trying to find the different pollen germination ability in rice at different temperature regime. I read some studies, they mentioned they incubated in room temperature for 2 hours. But you mentioned they loss the viability after 6 mins. Do you have any recommendation for the incubated time. Have a nice day!