| A. edgeworthii Benth.is annual winding herb plant which belongs to legume. In this examination, A. edgeworthii Benth. seed's configuration was observed. Discussing characteristic of hardseed and germination, the A. edgeworthii Benth. seed were process in different temperatrue, sulfuric acid, hot water, mechanical treatment etc. The seed development of A. edgeworthii Benth. were observed using paraffin sectioning method by microscope. The seed coat and cross section of mature seeds were investigated by scanning election. With roots, stems, flowers and leaves as materials, the morphological characters were observed. The process of mitotic division was observed, the karyotype and the numbers of metakinesis cells and chromosome were investigated with different pretreatment agents by using root tip squashed method. With inflorescence as material,the meiosis of pollen mother cell were observed, accordingly providing basis for genetics and taxonomy.Taking pollen mother cells as research materials for investigating meiosis, and providing basis to genetics and taxonomy of A. edgeworthii Benth. The results are as follows:1. The ground seed of A. edgeworthii Benth. was oblate, the color of seed coat that with gray and white spot on it was dark brown. There was smooth, lustrous and hard wax on the surface which was leather qualitative, Hard seed percentage was 98.3%.The seed size was 3.38 mm long,3.02 mm wide, and 1.88 mm deep,and the seed weight was 15.32 gramme/one thousand seeds.The color of seed coat of the underground seed of A. edgeworthii Benth. was brown, and there was brown tomentose and different sizes purple dot, and the morphology of underground seed was suboblate and the sizes of it were different, the minimum diameter of underground seed was 4 mm～5 mm and the maximum diameter was 15mm. The content of fat, protein and starch of the ground seed were 49.37%,19.27%,14.84% respectively. The content of fat, protein and starch of the underground seed were 38.51%,18.14%,39.60% respectively. 2.72 hours later, the water absorption of untreated seeds was very low, conversely the water absorption of seed coat broken seeds was as high as 109.2%, in addition seed coat broken seeds would imbibe fully in 6hours,and it shows that the seed coat was the mechanical barrier to imbibitions of seeds of A. edgeworthii Benth.3. Treating with concentrated sulfuric acid and machine could improve the germination percentage, germination vigor and germination index of seeds. The methods of treating seeds for 20min and breaking the seed coats by knife were best, the germination percentage was as high as 99.3%. The effect of treating with hot water was not obvious. The optimum temperature of germination of ground seeds was thermostatic of 20℃～30℃, and the optimum temperature of germination of underground seeds was variable temperature of 30/20℃.4. The ovule was fertilized and formed the zygote after flowering about 12 hours. The zygote was transversely divided into a terminal cell and a basal cell in 2 days after flowering. The proembryo continued cell division in very directions forming globular embryo and then heart-shaped embryo, in which the cotyledons primordium began to occur. In 24 days after flowering, the embryo differentiated into matured embryo through Tropedo-shaped embryo(in 16 days after flowering). The endosperm cell formation began when the globular proembryo was formed, and the development of the endosperm was nuclear type. The mature seed of A. edgeworthii Benth. is the seed without endosperm. The outer integument developed into the seed coat,and inner integument is degraded.5. The special structure of seed coat and hilum were the main factor that caused hard seed. The cuticle and the palisade layer of seed coat arranged densely, which prevented water from infiltrating into the embyo.There was the hilum consisted of two layers of palisade cells and afissure on the hilum surface.With the maturity of seeds,the palisade cells became thicker,and the two layers of palisade cells of hilum differentiated completely,linked so closely that the fissuer was closed. As a result, the mature seeds were most hard seeds.6. The results revealed that the optimal root-sampling time was about 9:00～10:00 am.of the four chemicals used to pre-treating the root tips,saturated p-dichlorobenzene showed the best effect. The well-spread and clear mitotic metaphase chromosomes of A. edgeworthii Benth. were obtained,2n=2x=22,N=11.The karyotype analysis indicated that there was no satellites on all chromosomes.The arm ratio of 0 chromosomes was over 2,and the ratio of the longest chromosome to the shortest one was 1.51. The karyotype was 1A and the karyotype formulate was 2n=2x=22=20m+2sm.The relative length of chromosome composition was 2n=L+3M2+7M1,and the AS.K% was 57.63%. The karyotype of A. edgeworthii Benth.belongs to karyotype symmetrical.7. The meiosis in A. edgeworthii Benth. undergoes simultaneity cytokinesis.There were 11 bivalents appearing at the stage of diakinesis and there is no unpaired chromosomes.The microspores in tetrad stage showed symmetrical type. The meiosis of the pollen mother cells were closely related to the size of buds,indicating it was a typical diploid species. |
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