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41.
P. H. Sisco V. E. Gracen H. L. Everett E. D. Earle D. R. Pring J. W. McNay C. S. Levings III 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,71(1):5-15
Summary Differences in fertility restoration and mitochondrial nucleic acids permitted division of 25 accessions of S-type male sterile cytoplasm (cms-S) of maize into five subgroups: B/D, CA, LBN, ME, and S(USDA). S cytoplasm itself (USDA cytoplasm) was surprisingly not representative of cms-S, since only two other accessions, TC and I, matched its mitochondrial DNA pattern. CA was the predominant subgroup, containing 18 of the 25 accessions. The B/D and ME subgroups were the most fertile and LBN the most sterile. The exceptional sterility of LBN cytoplasm makes it the most promising of the 25 cms-S accessions for the production of hybrid seed. The most efficient means of quantifying the fertility of the subgroups was analysis of pollen morphology in plants having cms-S cytoplasm and simultaneously being heterozygous for nuclear restorer-of-fertility (Rf) genes. This method took advantage of the gametophytic nature of cms-S restoration. The inbred NY821LERf was found to contain at least two restorer genes for cms-S. Fertility differences were correlated with mitochondrial nucleic acid variation in the LBN, ME, and S (USDA) subgroups.Paper No. 9498 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 相似文献
42.
It has been suggested that the sociospatial organization of baboon progressions has a protective function in which the most
physically powerful troop members, the adult males, play a key role. This theory implies regularities in adult male progression
order for different species of savannah baboons with similar social systems. Quantitative progression data are available from
two such similar baboon species, olive and yellow, but not from the third, chacma. The order of movement of 15 adult male
chacma baboons was determined from 40 progressions observed at the Moremi Wildlife Reserve, Botswana. The chacma males were
most often found in the front sixth of progressions, next most often in the second sixth, and about equally often from there
to the rear. As expected from the protection theory, this frontal positioning is consistent with available quantitative data
from other species of savannah baboons. 相似文献
43.
Somatic hybridization of Lycopersicon peruvianum and Petunia hybrida was carried out to transfer cytoplasmic male sterility from Petunia to Lycopersicon. Cytological, morphological and biochemical analyses were performed to characterize the regenerated plants. Two regenerated plants, R3 and R6, were male sterile. R3 possessed chromosomes morphologically similar to those of both parental types. Leaf morphologies of these two plants and a third plant, R7, were intermediate between the two parents. The stability of RUBPCase was verified during parental plant development and after in vitro culture. Plant R7 presented a new form of the large subunit of RUBPCase. 相似文献
44.
Chris L. Schürmann Jan A. R. A. M. van Hooff 《International journal of primatology》1986,7(3):265-287
Recent field data indicate that MacKinnon’s model of the orang-utan’s sexual and agonistic activity needs to be revised. In
this model, male reproductive activity is concentrated in an extended phase of subadulthood and in early adulthood. According
to this model, the role of older adult males is primarily that of range guardian, and in that role they would ensure that
the offspring they had generated earlier would have safe access to food resources. This study presents cases suggesting that
subadult males, even though sexually active, may have low reproductive success. In previous studies adult males were shown
to display less sexual initiative than subadult males. In this study an adult male was at times involved infrequent mating
activity in response to proceptive activity of females in the course of consortship. This adult male proved to be a successful
breeder, thus refuting the hypothesis of adult male sterility. The female is most likely to conceive through cooperative mating
in lengthy consortships with the dominant resident adult male. We hypothesize that the extended subadult phase represents
a submissive strategy, allowing subadult males to remain in the home range of adult males but with minimal reproductive success. 相似文献
45.
46.
BERNARD J. CRESPI 《Ecological Entomology》1986,11(2):119-130
ABSTRACT.
- 1 Hoplothrips pedicularius (Haliday) (Thysanoptera: Phlaeothripidae), a tubuliferan thrips in which males possess greatly enlarged forelegs, lives in colonies on Stereum fungus.
- 2 Females oviposit onto communal egg masses, and males fight by grasping and stabbing with their forelegs in territorial defence of oviposition areas. Prolonged escalated fights occur between males who are of similar size.
- 3 Larger males usually win fights and become dominant at the oviposition area. Dominant males secure 80% of matings, and mate most frequently during oviposition periods, with an ovipositing female.
- 4 Smaller, subordinate males avoid fights and attempt to 'sneak’copulations. However, they occasionally challenge the dominant male. Challenges tend to follow copulations by the subordinate male and occur more frequently between males who are of similar size.
- 5 Subordinate males who eventually leave the oviposition area are larger than those who remain, have frequently challenged the dominant male, and have more frequently been stabbed.
- 6 Sexual dimorphism in thrips is associated with gregariousness, claustral habitats, female-biased sex ratios, and male winglessness. In thrips genera in which males exhibit foreleg armature, males are larger relative to females. The ecological circumstances promoting sexual dimorphism and male fighting in spatially-structured populations are discussed.
47.
甘蔗伤流液中保绿活性物质的分离与初步鉴定 总被引:1,自引:0,他引:1
通过化学与物理学方法,从甘蔗(Sugar-cane)伤流液中分离出五种活性因素,对离体叶片有不同程度的保绿效应。依其化学性质判断,应属嘌呤化合物,可能是细胞分裂素物质。 相似文献
48.
These studies were designed to evaluate the ability of the zona-free hamster ova bioassay to detect differences in fertility of boar sperm. In the first study, sperm from two previously infertile boars were compared to sperm from seven previously fertile boars. The percentage of zona-free hamster ova penetrated by sperm from the previously infertile boars was significantly lower than the percentage of ova penetrated by sperm from previously fertile boars (18% of ova penetrated vs. 83%, P < .001). In the 14 ejaculates from the previously infertile boars that had ejaculate motilities of 50% or greater, the percentage of zona-free hamster ova penetrated continued to be lower than in ejaculates from the fertile boars. One of the two previously infertile boars consistently had a normal semen analysis. The only two observed manifestations of his reduced fertility were his zero conception rate and the limited ability of his sperm to penetrate zona-free hamster ova. In the second study, females were inseminated with equal numbers of sperm from two previously fertile males and the paternity of offspring determined at birth. The experiment was replicated with four combinations of six boars. A high correlation was observed between the percentage of offspring sired and the ability to penetrate zona-free hamster ova (R = .89). Neither morphology nor the ability of the sperm to undergo an acrosome reaction during in vitro incubation was correlated with fertility in the competitive mating situation. These results suggest the zona-free hamster ova bioassay can improve the in vitro fertility assessment of fresh boar semen. 相似文献
49.
50.
鉴定了小伞山羊草(Ae.umbellulata)6条染色体的中国春添加系对T型细胞质雄性不育系育性的影响,发现UAD能较好地恢复T型不育系的育性,表明染色体A上携带有育性恢复基因。添加染色体A在提莫菲维细胞质背景中通过雄配子的传递率为15.6%。同时进一步证明中国春不含有恢复基因。 在体细胞染色体数为42的331个不育系与UAD的杂种衍生后代中选到18个可育株,并对部分植株进行了细胞学鉴定。其中040-5、061-1和061-4与中国春的杂种F_1的育性分离和染色体配对情况表明它们是含有来自小伞山羊草染色体A上的恢复基因的杂合易位系。 相似文献