| Dendranthema indicum var.aromaticum is a rare species with a rich flavor in the Chrysanthemum, and its flowers, leaves and roots have a rich aroma, which has important implications for improved varieties of chrysanthemum plants. This paper mainly studies the effect of induced polypliod of Dendranthema indicum var. aromaticum using colchicine solution soak seed method, shoot tips cotton titration, Variation of Polyploid plants in external morphology, cytology, and the number of chromosomes terms, and Dendranthema indicum var. aromaticum tetraploid and Dendranthema×gandiflorum ’niu9717’ floral characteristics observed, using in vitro germination, benzidine-hydrogen peroxide method to identify the highest pollen viability of their time, stigma most time, determine both hybridization index and different ways of hybrid seed case, This is carried out their hybridization experiments laid the theoretical foundation for the later. The main research results are as follows:When soaking the pre-sprout and grin seeds of the Dendranthema indicum var. aromaticum by colchicine solution to induce polyploidy, the induction rate of the grin seeds is slightly higher than the pre-germinated seeds, and the induction rate is as high as 14.50% when the grin seeds are soaked by 1000mg/L colchicine solution for 24 h. When cotton ball titration shoot tips of the Dendranthema indicum var. aromaticum by colchicine solution to induce polyploidy, and the induction rate is as high as 40.00% when stem tips are continuous titration by 1000mg/L colchicine solution for 7 days.From the external form, Polyploids of leaf color is more darker and greener than diploid plants, leaf relative more massiness, table surface increased, flower diameter increased obviously. From the perspective of cytology, Polyploids of under the epidermis stomata is significantly bigger than diploid, stomatal density obviously smaller than diploid plants, and chloroplast number in stomatal polyploid plants significantly greater than in diploid. From the number of chromosomes, Diploid plant chromosome number is 2n=2x=18, The chromosome number of the tetraploid plants is 2n=4x=36. In the end,301 strains of chimeras plants and 7 strains of tetraploid plants were obtained.After the exploration into the various steps in the chromosome number identification method, The most suitable conditions for root tablet of Dendranthema indicum var. aromaticum:First,0.002M 8-hydroxyquinoline pretreatment 7 h in 4℃ refrigerator, Second, use fixed fluid (anhydrous ethanol:glacial acetic acid = 3:1) fixed in the 4℃ refrigerator for 24 h, refuse to stationary liquid, distilled water rinse 2-3 times, again with 1 mol/L HCL solution in 60℃ water bath pot from 8 min, refuse to solution liquid, distilled water rinse 2-3 times, The most suitable colorings is Carbol fuchsin staining for 30 min.Tetraploid Dendranthema indicum var. aromaticum and Dendranthema×gandiflorum ’niu9717’optimal pollen germination medium are ME3+150 g/L PEG4000+150g/L Sugar+0.1 g/L Boric acid+0.1 g/L Ca2+. Tetraploid Dendranthema indicum var. aromaticum blossom in 4 d when pollen germination rate is as high as 64.63%, at 13:00 based on pollen germination rate is as high as 54.56%, blossom in 9 d,13:00-14:00 at the stigma can give the most. Dendranthema×gandiflorum’niu9717’blossom in 6 d when pollen germination rate is as high as 11.63%, at 13:00 based on pollen germination rate is as high as 9.26%, blossom in 4-5d,12:00-13:00 at the stigma can give the most. Their breeding systems are outcrossing (partial selfing infertility), need pollinators. Bagging compaction test results show that the tetraploid Dendranthema indicum var. aromaticum in emasculation, bagged, hand cross-pollination seed setting rate increased to 79.28%, Other conditions, seed setting rate is about 40.00%, of which the emasculation, bagging, under the condition of no pollination is not strong enough. |
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