Studies On N+1 Male Gamete Transmission Difference Of Distinct Trisomics In Chinese Cabbage

Trisomics 2.trisomics7.trisomics9 and trisomics 10 were experiment materials.which were cultured from microspore of homologous tetraploid of Chinese cabbage and had been appraised.To solve the problem of n+l male gamete transmission difference of distinct trisomics,meiosis behavior of pollen mother cell,tissue section observation of pollen development,pollen characteristic, physiology and biochemistry would have been studied.And it was analyzed that additional effects of extra chromosome of distinct trisomics influnced chromosome behavior at meiosis,pollen activity.seed set,n+l male gamete transmission.The results of study were as follows:1. Seed set was 50.35%,36.90%,17.90%,0 respectively after trisomics 2, trisomics 7,trisomics 9,trisomics 10 as male parent hybridized with diploid as female parent.N+1 male gamete transmission was 7.69%,3.57%,8.70%,0 respectively.2. There existed many abnormal phenomena during meiosis.Thress homologous chromosomes of trisomics associated as a trivalent or a bivalent and a univalent or three univalent during diakinesis and metaphase 1 ;Laggard chromosome and univalent separated in advance at anaphase I ,leading to distribution of 10-1-10,9-12,11-11,10-2-10,10-12,10-10,9-1-11 besides 10-ll;And there was distribution of 11-11-10-10, 10-10-10-12, 10-10-10-11, 10-11-11-11, 11-11-10-9, 10-10-10-10, 9-12-10-10, 9-9-11-11, 11-10-10-9, 12-10-9-11, 11-9-9-13, 10-10-10-9 at anaphase II ;n+l microspore frequency were different of four trisomics.These phenomna all reduced the transmission of each trisomic in various degree.3. Tissue section indicated:Pollen development courses of trisomics 2,trisomics 9 were normal basically.similarly to diploid.The tapetum cells oftrisomic 7 and 10 showed abnormal phenomenon at meiosis,but trisomic 7 recovered normality at other periods.Although the tapetum cell of trisomic 10 was normal at the stage of tetrad,abnormal at the stage of microspore when pollen was all aborted,so pollen abortion was the main reason for influencing n+l male gamete transmission of trisomic 10.4. Pollen regularity of trisomic 2 had no significance difference with that of diploid;Pollen regularity of trisomic 7 and 9 was lower than that of diploid significantly;Pollen regularity of trisomic 7 was the lowest;Trisomic 10 didn't scatter pollen.There was significantly positive correlation between pollen regularity and seed set,so the former could be regarded as an index predicting the latter.5. Pollen activity of trisomic 2,7,9 was lower than that of diploid significantly;Pollen activity of trisomic 7 was the lowest.Pollen activity had positive correlation with transmission rate significantly.6. N+l male gamete transmission of trisomic 2,7,9 had the relation with chromosome behavior at meiosis and with the degression of pollen activity.Besides,n+l male gamete fertilization ability and 2n+l embryo development ability perhaps could influnce it,too.Extra chromosome of each trisomc carried different heredity information(gene),leading to above factors changes in various degree /which caused n+l male gamete transmission difference of distinct trisomics.7. Soluble sugar,amylum and amino acid contents of four trisomics were lowe than that of diploid.