1. Abort microspore in crescent or irregular shape . 26.

2. The microspore lacks a large central vacuole.

3. Microspore abortion occurred after the tetrad formation.

4. Meiosis of microspore mother cells is synchronous or unsynchronous.

5. Complete disintegration of cytoplasm at stage of vacuolated microspore.

6. The sporogenous cell develops into microspore mother cell.

7. Cytokinesis of microspore mother cells during meiosis was simultaneous type, and pollen grains were 2-cell, it suggested that the Dioscoreaceae was rather primitive in Angiosperm.

8. Cytokinesis in the microspore is of the simultaneous type and microspore tetrads are mainly tetrahedral. Pollen grains are mainly 2-celled when shed.

9. During the meiosis of microspore mother cells, the amount of starches apparently increased in parenchyma around vascular bundle but there were no starches in tapetal and middle layer cells.

10. The reasons resulting in microspore abortion of alloplasm was the decrease of activities of SOD and CAT, and damage of membrane systems led by accumulated active oxygen.

11. Shrink of cytoplasm at stage of central nucleus microspore .21.

12. At the stage of meiosis prophase, microspore mother cell begin to accumulate callose wall.

13. Vacuolation of cytoplasm at stage of central nucleus microspore .20.

14. When the tapetum disintegrates gradually later, microspore mother cell has still not entered meiosis, finally disintegrated.

15. The results showed that the microspore abortion occurred at the stage of microspore mother cell, tetrads and uninucleate microspore.

16. Isolated Microspore culture is one of the Methods : To obtain haploid.

17. The nucleus in shrinking cytoplasm of microspore mother cell enters into diakinesis stage .16.

18. Staining with the improved carbolfuchsin- aniline blue fluorescence method is a convenient and efficient way to observe the behavior of the callose wall of microspore mother cells during meiosis.

19. Rape have established regeneration system of cotyledons, hypocotyls, protoplasts and microspore culture.

20. The experiment also proved that the genotypes of donor materials have an important effect on microspore embryogenesis rate.

21. There are several unusual phenomena in the development process of the microspore and male gametocyte of the sterile pollen, ( 1 ) The genesis is unusual in the early stage.

22. At late anther developing stage, the tapetal cells became to vacuolated, anther chamber was full of giant tapetum and the microspore degenerated completely.

23. The intine of the pollen began to form in the middle stage of uninucleate microspore.

24. However, the tapetal cells of sterile anter did not synthesis lipid material during microspore aborting.

25. Therefore the behavior of vacuome may be the earliest morphological index for microspore abortion.

26. The big (/microspore.html), empty and abortive pollen grains are abserred at the stage of uninuclear microspore.

27. At the end of the first mitosis of the microspore, a new cell wall is formed by the fusion of coated vesicles and the microtubules of the phragmoplast on the equatorial zone.

28. In recent 20 years with more studies of rapeseed microspore culture a perfect regenerative system of rapeseed microspore culture has been set up.

29. The tapetum of P. hortorum belongs to periplasmodial tapetum. The invasion into the locule occurs when microspore form large vacuole in its cytoplasm.

30. The archesporial cells differentiated from single archesporium , the meiosis of microspore mother cells were continuous type and tetrads were tetrahedral.

31. The microspore mother cells in plants exposed to low temperature develop numerous vacuoles and thus show thin cytoplasm. Plasmolysis and accumulation of lipid easily occur in these cells.

32. Low temperature and mannitol pretreatment favor the maintaining of microspore activity.

33. At the stage of microspore, the tapetal cells evidently degenerated, and starches in parenchyma around vascular bundle became large.

34. The microspore mother cells give rise to isobilateral tetrads by meiosis. Cytokinesis is successive. The mature pollen grains are 2-celled and are shed singly.

35. Potassium antimonate was used to locate calcium in the fertile and sterile anther of a thermo-sensitive genie male-sterile rice at microspore mother cell meiosis stage and at early microspore stage.

36. The stasis phenomenon of gynoecium development occurred in floral organogenesis of Reineckia and the abortion of microspore and ovule may be the important causes of its low seed bearing ratio.

37. Disintegration of cytoplasm at stage of central nucleus microspore .22.

38. The microspore culture technology has been widely applied in Brassica species nowadays.

39. At anaphase of mitosis, the organelles in microspore cytoplasm are concentrated in the future vegetative cell pole.

40. A row of microspore mother cells develop directly from the primary sporogenous cells.

41. After microspore mitosis, bicellular pollen contained a large vegetative cell and a small generative cell, and then the big vacuole disappeared.

42. The endogenous hormonal ratio was interdependent to the microspore abortion of radish.

43. However, the tapetal cells of sterile anther did not synthesis lipid material during microspore aborting.

44. Appropriate pretreatments are necessary conditions on promoting microspore embryogenesis in wheat (Triticum aestivum L. ).

45. The nucleus in shrinking cytoplasm of microspore mother cell enters into telophase .17.

46. Cytokinesis is of the simultaneous type and microspore tetrads are mainly tetrahedral.

47. When microspore mother cell preparing meiosis, abundant calcium precipitates appeared in cytoplasm of tapetal cells and microspore mother cells, and in callus wall surrounding the cells.

48. Some abnormal division had been observed at microspore mother cell meiosis stage, e. g. chromosome pairing abnormally, aberrant dyad formation and asynchronous dyad division.

49. The primary sporogenous cells functioned directly as microspore mother cells and were arranged in a single row in a microsporangium.

50. It is suggested that the microspore abortion in male-sterile anther would he attributed to premature degeneration of middle layer and tapetum.

51. Complete disintegration of cytoplasm of crescent or irregular shape of microspore .25.

52. Objective: The aim of this work is to probe into micro - morphological character of microspore of Selaginella and their significance in Taxonomy.

53. Crescent or irregular shape of microspore at stage of central nucleus .24.

54. Through ultra-structure observation, it is found that the microspore of Jin A began to abort at the stage of sporogenous cell division.

55. Cell layers of powder chamber wall and middle-level were increased, tapetum cells were hypertrophied and sporogenous cells or microspore mother cells were disaggregated.

56. In the process of litchi flower differentiation, the microspore abortion induced by external ethylene starts from the transition period(from sporogenous cells to microsporocytes).