caa a22 4500 445322748 CHVBK 20180317142709.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s10681-011-0461-7 doi (NATIONALLICENCE)springer-10.1007/s10681-011-0461-7 Cytological mechanism of 2 n pollen formation in Chinese jujube ( Ziziphus jujuba Mill. ‘Linglingzao') [Elektronische Daten] [Zhihui Xue, Ping Liu, Mengjun Liu] In order to elucidate the cytological mechanism of 2n pollen formation in Chinese jujube, a cultivar named ‘Linglingzao' (2n=2x=24) which produces relative more 2n pollens naturally was employed for microsporogenesis analysis. Chromosomes paired in 12 bivalents at diakinesis and the first meiotic division was normal, whereas, the second division was characterized by frequent abnormal spindle orientation (parallel and tripolar spindles). Perpendicular, tripolar, and parallel spindles at metaphase II accounted for 72.93, 17.22, and 9.85% respectively. Perpendicular and tripolar spindles led to tetrads and triads formation respectively. Two types of parallel spindles were observed and a significant association correlation (r=0.84, P<0.05) between parallel spindleII (fused spindles) and dyads was found which meant only fused spindles can form dyads, while parallel spindleI with a long distance between two sets of chromosomes seemed to lead tetrad formation. At tetrad stage, the observed frequencies of tetrads, triads and dyads were 80.99, 16.40, and 2.61% respectively. By the rule that each tetrad can form four n pollens, each triad can form one 2n pollen and two n pollens, each dyad can form two 2n pollens, the frequency of 2n pollen estimated was 5.71%. Based on the pollen diameter difference between n and 2n pollens, frequency of 2n pollen observed was 6.15%. No significant difference was observed between frequency of 2n pollen estimated and that of observed. The results indicated that, tripolar spindles and fused spindles at metaphaseII followed by more triads and few dyads formation at tetrad stage were responsible for the production of 2n pollen in Chinese jujube. 2n gametes observed correspond to first division restitution. Research on the cytological mechanism of unreduced pollen will provide a platform for unreduced pollen induction and polyploidy breeding in Chinese jujube. Springer Science+Business Media B.V., 2011 Meiosis nationallicence Triads nationallicence Dyads nationallicence 2 n gametes nationallicence Polyploidization nationallicence Xue Zhihui Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut Liu Ping Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut Liu Mengjun Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut Euphytica Springer Netherlands 182/2(2011-11-01), 231-238 0014-2336 182:2<231 2011 182 10681 https://doi.org/10.1007/s10681-011-0461-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10681-011-0461-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xue Zhihui Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut NATIONALLICENCE 700 1- Liu Ping Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut NATIONALLICENCE 700 1- Liu Mengjun Research Center of Chinese Jujube, College of Horticulture, Agricultural University of Hebei, No. 289, Lingyusi Road, 071001, Baoding, People's Republic of China aut NATIONALLICENCE 773 0- Euphytica Springer Netherlands 182/2(2011-11-01), 231-238 0014-2336 182:2<231 2011 182 10681 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer