Hi,

I think the partially stained pollen would be counted under sterile pollen becoz they are abnormal and even they take a little stain they could fail to germinate properly. So you can go for germination test to check  their viability. The unstained would not germinate and the partially stained if germinate would produce a shorter pollen tubes as compare to the normal one and hence unable to fertile the egg cell and central cell. The paper attached below can help you in understanding the matter.

Hi,

I think the partially stained pollen would be counted under sterile pollen becoz they are abnormal and even they take a little stain they could fail to germinate properly. So you can go for germination test to check  their viability. The unstained would not germinate and the partially stained if germinate would produce a shorter pollen tubes as compare to the normal one and hence unable to fertile the egg cell and central cell. The paper attached below can help you in understanding the matter.

Hi Hilali

If you consider the starch content of pollen as a fertility index, then partially stained pollen are partially fertile. This means they may germiante on the stigma but may fail to affect fertilization because their pollen tubes may fail to grow efficiently to deliver the pollen nuclei to the ovary.  It is starch that drives pollen tube growth when hydrolozed into osmotically active sugars upon pollen germination. If you are assessing pollen fertility, I would suggest you group your data in more than two categories like you said, because in the end, the whole thing is relative. I mean by relative that partially fertile pollen could affect fertilization under omptimum conditions and fully fertile pollen could fail to do so under harsh conditions.

Good luck

Thank you all for help. @Gaber M Abogadallah, if partially fertile pollens affect fertilization, in such case, should they counted as fertile pollens in calculating percentage pollen fertility?

Hi Saleh

Pritu and Gaber have explained it in detail. I think you can consider it as fertile pollen if the stained portion of a partially sterile pollen is more than 2/3. For the proper estimation of pollen fertility you can do germination test to check pollen viability.

To avoid problems like this, grow them on pollen germination medium and count the ones that have germinated after 16 and 24h. There is no logic way of classifying partially stained pollen as fertile or non-fertile, since by nature the answer will be somewhere in between.

The observations you carried out provided an information on stainable pollen, not about pollen viability itself. You have several other methods that give you a better indication on the fertility of pollen, being the most accurate probably pollen germination in vivo on a compatible receptive stigma. This test is not always possible, so you rely on some other features of pollen grains to "estimate" pollen fertility: pollen germination in vitro, tetrazolium test, FDA STAINING, IKI, and many more. When in vivo pollination can not be performed I prefer FDA. Weakly stained pollen after IKI application are probably unable to achieve fertilization, which is the (main) reason for what pollen grains are produced for. 

I am giving farmulai for calculation of pollen fertility and sterility:

Pollen fertility test (%) = number of stained pollen / Total number of pollen X 100 

Pollen sterility test (%) = number of unstained pollen / Total number of pollen X 100

Hi

The question was put forth three months back. Hope you have already done the experiment  using IKI. Recently I read in an article (Pollen Dispersion, Pollen Viability and Pistil Receptivity in Leymus chinensis) that IKI is not the best option since it also stains heat killed Pollen. Also in several papers TTC or MTT is recommended . Finally the results have to be correlated with in vitro germination for accuracy.

Proportion of fertile pollen grains or stained pollens out of whole mass of pollen as counted.

Foumula:

Pollen fertility % = No. of fertile pollen grains/Total no. of Pollen grainsx 100.

Kindly follow the research paper

Article Identification and evaluation of aromatic short grain and co...

proportion of stained pollen in the mass of pollen and expressed as percentage. partially stained pollen grains are counted as non fertile