Hello,

In fact, the variability of pollen sizes is exist ...and it is statistically correct for the phenomenon of development.

See publication of Pojidaev Andrey from Lab. of pallinology St Petersburg

Best regards

Maybe it is due to cytomixis? You do not specify the plant species You are working on, but the phenomenon is highly probable in polyploids (and many crop species are polyploids). For some more information, I reccommend checking for example this paper: https://www.ias.ac.in/article/fulltext/jbsc/033/03/0371-0380

Best regards,

Jacek

I agree with Marpha. Pollen size varies with maturity of the flower anther, but also due to climate. I have found that pollen during drier episodes can be considerably smaller than during episodes of wetter climate. But during these episodes, the mean size of the pollen grains from an anther will be bigger or smaller. Variation of grain size from a single anther is probably due to flower maturity.

HYPOTHETICAL WAY OF POLLEN APERTURE PATTERNING. 2. FORMATION OF POLYCOLPATE PATTERNS AND PSEUDOAPERTURE GEOMETRY

Pozhidaev A.E.

Review of Palaeobotany and Palynology. 2000. Т. 109. № 3-4. С. 235-254.

14

7

HYPOTHETICAL WAY OF POLLEN APERTURE PATTERNING. 1: FORMATION OF 3-COLPATE PATTERNS AND ENDOAPERTURE GEOMETRY

Pozhidaev A.E.

Review of Palaeobotany and Palynology. 1998. Т. 104. № 1. С. 67-83.

18

8

POLLEN MORPHOLOGY OF THE GENUS AESCULUS (HIPPOCASTANACEAE): PATTERNS IN THE VARIETY OF MORPHOLOGICAL CHARACTERISTICS

Pozhidaev A.E.

Grana. 1995. Т. 34. № 1. С. 10-20.

14

9

POLYMORPHISM OF POLLEN IN THE GENUS ACER (ACERACEAE): ISOMORPHISM OF DEVIATE FORMS OF ANGIOSPERM POLLEN

Pozhidaev A.E.

Grana. 1993. Т. 32. № 2. С. 79-85.

10

10

THE ORIGIN OF THREE- AND SIXCOLPATE POLLEN GRAINS IN THE LAMIACEAE

Pozhidaev A.

Grana. 1992. Т. 31. № 1. С. 49-52.

Thank you all for the suggestions. And thank you Marpha for the references, i was just looking at articles of Pozhidaev to find some answers. I also came across an article about pollen from two-flowered Erythronium grandiflorum (Cruzan 1990) and pollen from the flower that opens first is significantly larger than from the flower that opens second. However, pollen grains within the same flower are more or less of the same size.

Certain plants produce two different types of pollen grains such as buckwheat and crepe myrtle. Thus, the taxon you are examining might be another example.