Cytogenetics of Hybrids Among Perennial Species of Glycine Subgenus Glycine

1979 ◽  
Vol 27 (6) ◽  
pp. 713 ◽  
Author(s):  
E Putievsky ◽  
P Broue

A cytogenetic analysis based on F1 hybrids of some of the perennial species of Glycine subgenus Glycine Verdc. shows that G. clandestina and G. canescens are closely related and further, that either one of these diploid species could have provided one genome for the tetraploid form of G. tomentella. On the other hand, it appears that G. falcata and G. tabacina are distinctive species which are not closely related to the other three species. The tetraploid form of G. tomentella is genetically heterogeneous and crosses between certain types yield F1s with low pollen stainability which fail to set seed under conditions of self-fertilization.

2013 ◽  
Vol 55 (2) ◽  
pp. 141-165
Author(s):  
Janina Skrzyczyńska ◽  
Jolanta Marcinik

Attempt of comparative analysis of the segetal flora of Siedlce City with similar flora of areas of arable lands of the Siedlce Upland is presented in the paper. Received results show the larger value for urban flora of apophitysm coefficient - 63,3% (61% for Upland), flora modernization - 0,52 (0,42 for Upland) and flora lability - 19 (15 for Upland). On the other hand segetal flora of the Siedlce Upland is characterised by larger synanthropization coefficient - 104 (93 for the city). As to other differences, considerable larger participation of perennial species in the flora of the city (45,5% Siedlce; 37,1% Upland) is noteworthy. Moreover the occurrence of juvenile forms of arborescent species and plants running wild from gardens and parks, e.g.: <i>Mathiola incana, Aesculus hippocastanus, Sedum reflexum, Nigella damascena, Helianthus tuberosus</i> among species weeding urban cultivation is clearly noticeable.


2002 ◽  
Vol 80 (10) ◽  
pp. 1096-1102 ◽  
Author(s):  
Takashi Kimura ◽  
Hiroshi S Ishii ◽  
Satoki Sakai

To examine the influence of individual size and time of pollination on selfed and outcrossed seed production, we conducted hand-pollination experiments in 2000 and 2001 in the perennial herb Iris gracilipes A. Gray (Iridaceae). Small individuals produced outcrossed seeds to a greater extent than selfed seeds, whereas large individuals produced not only outcrossed seeds but also selfed seeds. On the other hand, when half of all flowering shoots of an individual were removed, both selfed and outcrossed seeds were produced independent of individual size. Flowers that opened earlier within the same flowering shoots were likely to produce outcrossed seeds, while those that opened later within the same flowering shoots produced relatively more selfed seeds than did the flowers which opened earlier. Thus, the ratio of the numbers of selfed to outcrossed seeds produced may differ between small and large individuals. These results suggest that plants regulate selfed- and outcrossed-seed production depending on their sizes and flowering sequence.Key words: self-fertilization, individual size, flowering sequence, Iris gracilipes.


2019 ◽  
Vol 13 (4) ◽  
pp. 389-402 ◽  
Author(s):  
Ekaterina D. Badaeva ◽  
Sergei A. Surzhikov ◽  
Alexander V. Agafonov

Thinopyrum bessarabicum (T. Săvulescu &amp; T. Rayss, 1923) A. Löve, 1980 is diploid (2n=2x=14, JJ or EbEb), perennial self-fertilizing rhizomatous maritime beach grass, which is phylogenetically close to another diploid wheatgrass species, Agropyron elongatum (N. Host, 1797) P. de Beauvois, 1812. The detailed karyotype of Th. bessarabicum was constructed based on FISH with six DNA probes representing 5S and 45S rRNA gene families and four tandem repeats. We found that the combination of pAesp_SAT86 (= pTa-713) probe with pSc119.2 or pAs1/ pTa-535 allows the precise identification of all J-genome chromosomes. Comparison of our data with the results of other authors showed that karyotypically Th. bessarabicum is distinct from A. elongatum. On the other hand, differences between the J-genome chromosomes of Th. bessarabicum and the chromosomes of hexaploid Th. intermedium (N. Host, 1797) M. Barkworth &amp; D.R. Dewey, 1985 and decaploid Th. ponticum (J. Podpěra, 1902) Z.–W. Liu &amp; R.–C. Wang, 1993 in the distribution of rDNA loci and hybridization patterns of pSc119.2 and pAs1 probes could be an indicative of (1) this diploid species was probably not involved in the origin of these polyploids or (2) it could has contributed the J-genome to Th. intermedium and Th. ponticum, but it was substantially modified over the course of speciation


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
K.H. Westmacott

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.


2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.


1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  

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