共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
World Journal of Microbiology and Biotechnology - 相似文献
7.
8.
9.
10.
Before the antibiotic’s era, the clinicians have shown the relation between epididymitis and Infertility. At the moment, venerial diseases are the principal cause of Epididymitis by the young man. The early diagnosis of the urethral infection (acute or not) associated with a suitable antibiotherapy will allow to protect the fertility. 相似文献
11.
12.
M. G. M. Van Creij J. L. van Went D. M. F. J. Kerckhoffs 《Sexual plant reproduction》1997,10(4):241-249
The development of the embryo and endosperm has been investigated in an intraspecific Tulipa gesneriana cross and in the incongruent cross T. gesneriana ×T. agenensis at intervals of 10 days, from 12 to 82 days after pollination (DAP). In both tulip crosses, the zygote gives rise to an apparently
undifferentiated cell mass, the proembryonal cell mass, on which a suspensor then develops. Subsequently, a globular embryo
is formed on top of the suspensor. This embryo finally elongates, giving rise to a spindle-shaped embryo. The cellular endosperm
fills the whole embryo sac in mature seeds, except for a region immediately around the embryo. In both crosses, aberrant developments
were found. In the intraspecific T. gesneriana cross, the pollen tubes did not open in a number of ovules. In other ovules, the pollen tubes seemed to have opened, but an
embryo or endosperm was not found or only endosperm was observed. In the cross T. gesneriana ×T. agenensis, fewer pollen tubes entered the ovules than in the intraspecific T. gesneriana cross. The ovules with embryo and endosperm formation of the incongruent interspecific cross showed, in general, retarded
development in comparison with the intraspecific T. gesneriana cross. The first globular embryos and spindle-shaped embryos were found at the later fixation dates and the relatively lower
number of spindle-shaped embryos at 82 DAP had a shorter average length. The number of ovules with deformations in embryo
and/or endosperm development was also higher in the cross T. gesneriana × T. agenensis in comparison with the intraspecific T. gesneriana cross. Between 87% and 100% of the ovules with embryo and endosperm development showed normal development in the intraspecific
T. gesneriana cross, while in the incongruent interspecific cross, from 22 DAP, between 17% and 56% of the ovules showed normal development.
Of those ovules with aberrations in embryo and/or endosperm formation, about 80% had a deformed endosperm, of which more than
50% also contained a deformed embryo. Embryos of the incongruent cross might be saved by the application of embryo rescue
techniques.
Received: 10 December 1996 / Revision accepted: 23 April 1997 相似文献
13.
14.
15.
16.
17.
18.
19.