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从成熟卵子的核相与体外促熟,精子的顶体反应,受精膜的形成,极体的释放与雌雄原核的形成以及多精入卵方面综述了贝类受精细胞学的研究成果,并展望了这一领域的研究和应用前景。 相似文献
24.
将香榧(Torreya grandis‘Merrillii’)的未成熟合子胚置于SH+0.1 mg·L-1 NAA+500 mg·L-1AC+3%蔗糖+0.5 g·L-1 Gln培养基上暗培养45 d,诱导产生半透明颗粒状胚性愈伤组织;将胚性愈伤组织转入SH+20 g·L-1 PEG+10 mg·L-1 ABA培养基中暗培养3个月诱导体细胞胚。采用碘—碘化钾染色和石蜡切片技术对体胚起源、形态发育与细胞组织学进行了观察。结果表明:胚性愈伤组织起源于合子胚胚轴表皮或皮层细胞的对称分裂。胚性愈伤组织含有两类细胞,一种是细胞质浓厚、细胞核大、体积小的圆形胚性细胞,另一种是高度液泡化拉长的细胞。胚性愈伤组织包含由这两种细胞构成的原胚团Ⅰ、原胚团Ⅱ和原胚团Ⅲ,以及一些游离细胞。原胚团Ⅲ在无植物生长调节剂的SH基本培养基上形成原胚,原胚接入成熟培养基,历经球形、棒状、心形、鱼雷形胚后发育成子叶胚。将子叶胚转入萌发培养基后胚根伸长,胚芽发育长出针叶,形成完整的再生植株。同时在离体培养中合子胚胚柄处退化的裂生多胚也能重新发育形成胚体。在初生体胚发育过程中表面常伴有次生体细胞胚的形成。 相似文献
25.
There are many wild species of pigeonpea which are endemic to Australia. These wild species are cross incompatible with cultivated
species of Indian origin. Cajanus acutifolius is one such species which does not easily cross with cultivated pigeonpea. Interspecific pollinations lead to hybrid seeds
which were semi-shrivelled. Very few seeds germinated to give rise to F1 plants. Backcrossing the hybrid plants to C. cajan,
the male parent, gave rise to aborting seeds which did not germinate in vivo hence BC1 plants are obtained after saving the
aborting embryos in vitro. BC1 plants showed normal meiotic pairing, but had low pollen fertility. The reasons for embryo abortion and low pollen fertility
in spite of normal meiosis could be due to the effect of wild species cytoplasm.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
26.
Cajanus reticulatus var. grandifolius, endemic to Australia and a wild relative of the cultivated species, C. cajan, was successfully crossed with the latter as the female parent. The major wild species characters such as persistent stipules,
long pod hairs, pod shattering, brown seeds with grey speckles, and presence of seed strophiole were dominant in the hybrid.
For growth and branching habit, and leaflet, flower, pod, and seed size, the hybrid was intermediate between the parents.
The meiotic cells of the hybrid were found to have quadrivalents, trivalents, univalents,and showed reduced chromosome pairing
as revealed by the increased number of rod bivalents per cell at metaphase-I, and stickiness and precocious movement of chromosomes
to poles in the second division. In comparison to the parents, the hybrid had fewer pods and seeds. However,these anomalies
in the interspecific hybrid are not significant enough to preclude the gene transfer from C. reticulatus to the cultivated species through a sexual route.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
27.
Arachis glabrata Benth, variety glabrata collector GK 10596 (PI276233; ICG 8176) belonging to section Rhizomatosae has resistance to rust, late leaf spot and viral diseases. A. hypogaea L. cv MK 374 (section Arachis) is susceptible to rust, late leaf spot and to the viral diseases peanut stripe, peanut mottle and peanut bud necrosis. Hybrids
between A. hypogaea cv MK 374 and A. glabrata were produced after inter specific pollinations and embryo culture. The hybrids produced had morphological characters of
both parents plus floral abnormalities not seen in either parent. It was possible to identify the hybrids by esterase isozyme
analysis when still in culture. Cytological research showed variable chromosome association and also homeology between the
genomes of A. hypogaea and A. glabrata. The hybrids inherited resistance to rust, late leaf spot, peanut bud necrosis and peanut stripe diseases from the pollen
parent A. glabrata.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
28.
A plant with drastically reduced vigour was observed in a population of diploid barley (Hordeum vulgare) raised from seeds exposed to gamma radiation. Cytological studies revealed that the plant was nullisomic with 2n = 12. At meiosis, regular formation of 6 bivalents was observed. The plant was totally sterile and produced neither stainable pollen nor seed. 相似文献
29.
Summary Crossing experiments involving the various groups of Solanum macrocarpon L. complex, including wild (dasyphyllum), semi-wild and cultivars produced fully fertile F1 and F2 hybrids. This confirmed earlier findings that these groups belong to the same biological species. S. macrocarpon complex and S. linnaeanum Hepper ex Jaeger are isolated by reproductive barriers. F1 and F2 hybrids between various groups of S. macrocarpon showed heterosis. F2 superior hybrids were isolated as candidates for the future breeding programmes. Most wild-type traits like prickliness, hairiness were dominant to those possessed by cultivars. Relatively resistant hybrids to pest attack were noted. S. macrocarpon complex and S. linnaeanum are diploids (2n=24). The overall nature of the karyotype suggests that the two are related. The F1 hybrids between the cultivars of S. macrocarpon and the wild group (S. dasyphyllum) showed normal meiosis. A lack of isolating barriers confirmed that S. macrocarpon complex constitute a single biological species. 相似文献
30.
研究了以陆地棉(Chirsutum)晋棉7号、冀合321、冀棉713、珂字棉321、珂字棉201等品种为外植体的体细胞培养获得再生突变不育株的形态性状及减数分裂过程中染色体的行为。与再生可育株相比,不育株的株型、分枝、叶、花各器官均较小。花柱、柱头、花丝、花药小而呈萎缩干瘪状,花药不开裂。减数分裂不正常,染色体普遍丢失减少,不能正常配对,出现很多单价体和染色体桥。产生二分体、三分体和多分体,也有正常的四分体。雌配子体和雌配子发育也不正常,胚囊结构不完整,反足细胞迟迟解体,表现雌雄不育。 相似文献