Cytology of 2n Pollen Formation in Nonastringent Persimmon

<正> Cytological mechanisms of 2n pollen formation in ’ Zenjimaru’ nonastringent persimmon (Diospyros kaki L.f.) were studied. The following abnormalities in meiosis were found to be responsible for the production of 2n pollens: (1) disoriented spindles, including parallel, fused and tripolar spindles, were formed at metaphase II and anaphase II; (2) the nuclei at telophase II were arranged to two poles, each of which contained two nuclei, or to three poles, one of which contained two nuclei, the other two contained one nucleus respectively; (3) dyads and triads were produced at the tetrad stage. The dyad would develop into two 2n pollens, and the triad would develop into one 2n and two n pollens. The 2n pollens produced by this mechanism were genetically equivalent to FDR (first division restitution) gametes, thus providing a potential value for sexual polyploidization.