Hi Nhu and all, As a biochemist, I should understand this better than I do. In fact, I looked into the literature on self-incompatibility, but that was years ago. I'm pretty sure the heat denaturation is producing changes to proteins in the pollen as well as to polysaccharides. I seem to recall that the stigma response to self-pollen was to produce RNase that destroyed new RNA being produced in the pollen tube as the pollen tube tries to grow. Note that one usually uses heat-inactivated fertile (non-self) pollen as the promoting agent, and the heat inactivation is just so you don't get any offspring from the promoter parent. You could get the same affect by mixing live fertile (non-self) pollen with the self pollen, if you don't mind getting a bunch of the hybrid seeds as well as the self-seeds. This is probably one of those annoying biochemistry puzzles where the inhibitor of my inhibitor is my activator. It could easily give me a headache! Jim On Mon, Feb 15, 2016 at 1:11 PM, Nhu Nguyen <xerantheum@gmail.com> wrote: > Hi Uli, > > Yes, you are right. With more accurate description, it would be most useful > to different people. I have an old model that is 400 Watts. Power at 400 > watts and 15-20 seconds is what I typically use. If you have more powerful > models, you can scale it down. According to what I can find on the > internet, the scaling is linear. > > For example, if you have a 1000 Watt machine, my output would be 40% as > powerful as yours. You should reduce the power on your machine to the 40% > power setting. Alternatively, you can reduce cooking time to 6-8 seconds at > 100% power. > > David mentioned that perhaps drying is a cause. I don't think that is the > case since air drying of pollen doesn't help to bypass > self-incompatibility. You'd need some really fancy machines or some > chemical reactions to see if the polysaccharides have changed - we need a > chemist. Jim Shields, where are you? > > I searched around a little bit and it appears that microwaves are often > used to solubilize polysaccharides or cause change in structure of highly > branched polysaccharide molecules. So it appears that my hypothesis of > microwaves changing the polysaccharides that causes self-incompatibility > may hold some water. > > Nhu > > On Mon, Feb 15, 2016 at 1:58 AM, Johannes Ulrich Urban < > johannes-ulrich-urban@t-online.de> wrote: > > > What is half strength in a microwave? Can you give the setting in Watt? > > With an indication in Watt the energy applied would be clear, then the > > length of exposure to that energy can be dealt with separately. I would > > guess that both the level of energy exposure and its length do matter. > > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ > -- James Shields jshields46074@gmail.com P.O. Box 92 Westfield, IN 46074 U.S.A.