L. Rihova et J. Tupy, Manipulation of division symmetry and developmental fate in cultures of potato microspores, PL CELL TIS, 59(2), 1999, pp. 135-145
The effect of media composition on microspore culture was investigated in o
ne tetraploid and two diploid potatoes. The viability of microspores isolat
ed from 4.5 to 5 mm buds was in the range of 33 to 52%. In media for anther
culture, microspores showed no further development and lost viability with
in 2 days. In M1 medium containing mineral components, sucrose, uridine, cy
tidine, myo-inositol, glutamine and lactalbumin hydrolysate, 18 to 37% of m
icrospores underwent mitosis within 14 days. Up to 95% of the divisions wer
e symmetric and produced equal nuclei. Some symmetrically divided microspor
es eventually produced structures with 3 to 10 nuclei. The proportion of th
e total microspore population producing multinuclear structures reached 9%
in diploid clones responsive to anther culture and 1 to 2% in recalcitrant
cv. Borka. Symmetric mitoses in M1 medium were induced in the presence of g
lutamine and lactalbumin hydrolysate. Nucleosides and myo-inositol had no e
ffect on microspore division. In the absence of all organic components exce
pt sucrose, most mitoses were asymmetric, formation of multinuclear structu
res was reduced and most pollen accumulated starch indicative of gametophyt
ic fate. In complete M1 medium, starch accumulation was suppressed. Suppres
sion also occurred in asymmetrically divided microspores, indicating a dire
ct inhibition of pollen development independent of the mode of microspore d
ivision. This inhibitory effect of M1 medium might present a stress which t
riggers the induction of symmetric microspore division and subsequent forma
tion of multinuclear structures.