Method of fixing the heterotic effect—implementation on plants (on the hundredth anniversary of the birth of V.A. Strunnikov)

The article is devoted to the 100th anniversary of the outstanding world-renown Russian scientist Vladimir Alexandrovich Strunnikov, Academician, Professor, Head of Group of Developmental Cytology and Sex Regulation at Koltzov Institute of Developmental Biology and Head of genetic studies on silkworms in a number of sericulture institutes in CIS. Laureate of the State Prize of the USSR (1981), Hero of Socialist Labor (1990), awarded the I.I. Mechnikov Gold Medal, Academy of Sciences of the USSR (1981), founder of the theory explaining the origin of heterosis. One of his most significant achievements is the “Methods of Fixing the Heterosis Effect,” which makes it possible to abandon the production of hybrid seed and increase the yield of many crops by 20–50%. Fixing the gene complexes that determine the heterosis effect will become the “springboard” that will allow obtaining even more productive heterotic hybrids on the basis of new-generation varieties. The efficiency of this method in plant objects at the organismal and molecular levels was shown in the All-Russia Research Institute of Rice. A modification of this method reducing its laboriousness and increasing its efficiency was developed.     

A critical review of S. V. Meyen’s “Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record”

Meyen’s “Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record” departs from the usual Botanical Review article that provides the botanical community with a synthesis of the state of knowledge and understanding of an individual segment of botany, i.e., an interpretation of progress in a specialty for the nonspecialist. Instead, this article appears intended to challenge paleobotanists to reconsider traditional views of the interrelationships of the various gymnospermous groups and the concepts on which they were based. A classification scheme is presented which divides gymnosperms into the Ginkgoopsida, Cycadopsida and Pinopsida. These classes are based on Meyen’s analysis of the structural variation in gymnosperms and his interpretation of homologies of various organs. Too often, however, key plants are reconstructed from parts known only in association and relationships are tied to assumptions of homology that have yet to be documented. The result has value in providing a succinct summary of gymnospermous structure and variation in the different groups. It is also commendable in its attempt to explain and use concepts and terminology designed especially for gymnosperms. This critique shows that in many cases there are alternative interpretations that also fit the evidence.     

Nageiaceae—A New Gymnosperm Family

A new monotypic gymnosperm family, Nageiaceae D. Z. Fu, is separated from Podocarpaceae. It is characterized by having multinerved leaves without costae, and primitive shoot-like female reproductive organs (female strobili). The new family contains a single genus consisting of 2 sections, 5 species and is distributed along the western coast of the Pacific, from low coastal mountains of eastern and southern Asia to the Phillipines and Papua New Guinea. The first species in the Nageiaceae was described as an angiosperm, Myrica nagi Thunb. (1784), but it was soon recognized to be a gymnosperm belonging to a new genus, and was renamed as Nageia japonica Gaert. (1788). The generic name, Nageia, however, has seldom been used, and the members of Nageia have generally been treated as an isolated section of Podocarpus in the Podocarpaceae. When revising the Podocarpaceae, De Laubenfels (1969) established a new genus Decussocarpus based on Nageia, but several years later (1987) he revived the old generic name, Nageia. Page ( 1988,1990)considered Nageia to be a valid generic name and redefined it as a natural genus. The distinctive,broadly lanceolate, multinerved leaves (without costae) of Nageia are rather unusual in gymnosperms,only being similar to those of Agathis in the Araucariaceae, their leaves are also similar to each other in anatomy. For example, there are many single vascular bundles arranged parallelly, between which occur sclerenchyma cells in the mesophyll. Apparently,leaves in Nageia are rather similar both externally and internally to paleogymnosperm cordaitean leaves, and sclerenchyma cells found in Nageia might be the remains of straps between veins in cordaitean leaves. In addition to leaf characters, the large and nearly round pith of the young shoot in Nageia appears to be a reminiscent of the large pith in cordaitean stem. The female reproductive organs (female strobili ) in Nageia are shoot-like. The female strobilus has a sterile terminal bud, and several opposite or subopposite sterile scaly bracts on its axis; two opposite megasporophylls are found near the axis apex and both have an anatropous ovule which is almost entirely covered by the megasporophyll; a bract is partly adnate to the lower back of the megasporophyll;mature arillate seeds are 1-2 or occasionally 3 in number; the axis becomes woody when the seeds mature, but in some species (N. wallichiana) the upper part of the axis becomes fleshy (in the shape of a receptacle), in which no distinct boundary was found between the fleshy receptacle and the woody part, and both have the same scaly bracts or traces. Many characters in Nageia are distinctly different from those in Podocarpus. Leaves in the Podocarpaceae have distinct midribs; in Podocarpus, the reproductive organ, which was generally thought to be similar to that in Nageia, has no terminal bud, and its bract is entirely free from the lower back of the megasporophyll, the fleshy receptacle is derived from both the axis and the sterile bracts (except the lowest two), and the female strobilus at the seed stage has a secondary stalk. The multinerved leaf in Nageia can rarely be found in most of the living gymnosperms except in some rather isolated groups, such as Araucariaceae, Ephedraceae,Ginkgoaceae and Welwitschiaceae. Paleobotanical evidence shows that multinerved leaves have been found in all of the geological ages from the Paleozoic to the present, and such a shoot-like female reproductive organ as in Nageia was found in some paleogymnosperms. It is very difficult to determine the systematic positions of these fossil plants because of lacks adequate material of reproductive organs or even lack of complete vegetative organs. The vascular system and leaf characters of gymnosperms are considered to be very conservative, and the fact that the common leaf shape and venation exist in both fossil and living gymnosperms could imply that there exists a multinerved-leaved evolutionary line ( M-line ) in gymnosperms, which could be traced back to the paleogymnosperm cordaitean plants or even older ones with multinerved leaves. The different types of the female strobili (female reproductive organs) of living gymnosperms, regardless of having one or only several seeds without a typical cone or many seeds with a cone, might have been derived from shoot-like or spikelike female reproductive organs possessed by their common ancestor.The fossil eviden ce shows that the typical cone similar to those of living gymnosperms first appeared in the Jurassic, much later than the single-seeded fossil plant without cones. The seed fossil appeared in the late Devonian Period. It is very difficult to infer the relationships among living gymnosperms, which are hardly derived from one another. But an analysis of the strobili, including the axis structure and position, number, morphology and degree of adnation of the phyllomes on them, would be helpful to the study of their phylogeny. It is evident, therefore, that the gymnosperms with leaves having a midrib might also have a rather long evolutionary course,but no transition between the midrib and multinerved patterns of leaf venation has so far been found in both living and fossil plants. Finally, it is noteworthy that the Nageiaceae are distributed along the western coast of the Pacific, where many primitive representatives, both in gymnosperms and angiosperms, still survive. This would be advantageous to the consideration of Nageiaceae as a primitive representative, or a descendant of fhe paleogymnos-perm cordaitean plants.     

A commentary on the G₂/M transition of the plant cell cycle

Background

The complex events of mitosis rely on precise timing and on immaculate preparation for their success, but the G₂/M transition in the plant cell cycle is currently steeped in controversy and alternative models.

Scope

In this brief review, the regulation of the G₂/M transition in plants is commented on. The extent to which the G₂/M transition is phosphoregulated by WEE1 kinase and CDC25 phosphatase, as exemplified in yeasts and animals, is discussed together with an alternative model that excludes these proteins from this transition. Arabidopsis T-DNA insertional lines for WEE1 and CDC25 that develop normally prompted the latter model. An argument is then presented that environmental stress is the norm for higher plants in temperate conditions. If so, the repressive role that WEE1 has under checkpoint conditions might be part of the normal cell cycle for many proliferative plant cells. Arabidopsis CDC25 can function as either a phosphatase or an arsenate reductase and recent evidence suggests that cdc25 knockouts are hypersensitive to hydroxyurea, a drug that induces the DNA-replication checkpoint. That other data show a null response of these knockouts to hydroxyurea leads to an airing of the controversy surrounding the enigmatic plant CDC25 at the G₂/M transition.     

Studies on the Constituents of Typha L.—IV. A Preliminary Study of Chemosystematics of Typha L.

From pollen grains of Typha davidiana, T. latifolia, T. angustata the same eight flavonoids have been isolated. They are identified as naringenin I, isorhamnetin II, quercetin III, isorhamnetin-3-O-(2^G-α-L-rhamnopyranosyl)-rutioside IV, quercetin-3-O-(2^G-α-L-rhamnopyranosyl)-rutinosida, V, isorhamnetio-3-O-rutinoside VI, isorhamnetino-3-O-neohesperidoside VII, kampferol-3-O-neohesperidoside VIII. Flavonoids of pollen grains of five species of Typha, including the above three species, were analysed by TLC with the result showing that the constituents in the pollen grains of the five species are very similar. The chemical comparison among Typha and Sparganium and 16 possibly related families shows that Typha is different from Pandanaceae or Pandanales and is similar to Restionaceae, Flagellariaceae, Juncaceae and Cyperaceae in some respects. Typha and Sparganium are very similar in many respects, and they could be treated in the same family, Typhaceae, which merit the rank of order, Typhales.     

The Phylogeny of Species of the Genus Saccharomycopsis Schiönning (Saccharomycetaceae) Based on the Partial Sequences of 18S and 26S Ribosomal RNAs

Eight strains of Saccharomycopsis species were examined for their partial base sequences of 18S and 26S rRNAs. The base sequences on the fingerprint segment showed three kinds of ACUAU, UCUAU, and AUAU. In the partial base sequences (positions 1451–1618, 168 bases) of 18S rRNA, all the strains of Saccharomycopsis species examined had 1–0 base difference except for the strains of Saccharomycopsis fibuligera (base differences, 5–4). In the partial base sequences on the positions 1611–1835 region (225 bases) of 26S rRNA, however, S’copsis vini had 15–11 base differences. The other species had 7–2 base differences. In the partial base sequences on the positions 493–622 region (130 bases) of 26S rRNA, the calculated percent similarities were 62–77. Discussion was made phylogenetically and taxonomically, especially on the separation of S’copsis fibuligera (≡ Endomyces fibuliger) from the genus Saccharomycopsis.     

Studies on the Chinese Woodsiaceae (3)—Phylogeny and Speciation

The history of the study on the woodsiodes is briefly surveyed in the paper. The family Woodsiaceae is recognized by the present author. The relationships among the species and the probable evolution of the family are discussed based on author's cytological and comparative morphological studies, and are indicated by Wagner's method, with numerical values as the indices. Woodsiaceae may have originated from the common ancestor of modern Dicranopteris and Sticherus of Gleicheniaceae, and evolved from it into two main branches, i.e., Woodsia and Protowoodsia. The origin of species through polyploid series are discussed, and W. andersonii, W. subcordata, W. alpina and Cheilanthopsis indosiosa considered as fertile allopolyploids; the probable way of speciation is also suggested for these species.     

Phylogeny of the α-crystallin-related heat-shock proteins

Summary Phylogenetic relationships were examined among 35 -crystallin-related heat-shock proteins from animals, plants, and fungi. Approximately one-third of the aligned amino acids in these proteins were conserved in 74% of the proteins, and three blocks of consensus sequence were identified. Relationships were established by maximum parsimony and distance matrix analyses of the aligned amino acid sequences. The inferred phylogeny trees show the plant proteins clearly divided into three major groups that are unrelated to taxonomy: the chloroplast-localized proteins and two groups that originate from a common ancestral plant protein. The animal proteins, in contrast, branch in accordance with taxonomy, the only clear exception being the -crystallin subgrouping of vertebrates. This analysis indicates that the small heat-shock proteins of animals have diverged more widely than have the plant proteins, one group of which is especially stable.Offprint requests to: N. Plesofsky-Vig     

A comparison of the refractile bodies (R-bodies) of certain bacteria—II. Effects of pH on the structure

The ‘R-bodies’ of Caedibacter taeniospiralis, an endosymbiont of Paramecium tetraurelia and Pseudomonas avenae, have been examined under a wide range of pH. They both unroll over a small range, but in both cases the process does not always proceed to completion. Acid pHs cause both to unroll. All the R-bodies of P. avenae at high pHs are wound which is not the case with Caedibacter. There are differences between the two bodies in the details of their unrolling. Caedibacter taenospiralis unwinds from the inside, whereas P. avenae unwinds from the outside. Detailed study of the unwound ribbon shows a difference in terms of roughness and smoothness of the two surfaces.     

A Report on the Evaluation of Exhibits—Mediscope 1961

Thirty-two educational exhibits presented by the Ontario Medical Association at the 1961 Canadian National Exhibition in Toronto in the exhibit known as “Mediscope 1961” were subjected to an evaluative study. Applying the criteria of educational effectiveness to each exhibit, relative ratings for each exhibit as well as the educational value of Mediscope as a whole were obtained. Quantitative data indicated that this venture in health education was a highly successful endeavour, as 80% of the criteria for educational effectiveness were met by all exhibits. In addition, the study emphasized the potential of educational exhibits in the field of public health education as well as education of specific groups.The desirability of similar studies is stressed. In addition to quantitative assessment of educational exhibits, such studies would disclose the impact of health information on the attitudes and behavioural changes on the part of the public.     

Refinements of and commentary on the silver staining techniques of Fernández-Galiano

The original ammoniacal silver carbonate staining technique and subsequent modification developed by Fernández-Galiano are useful for investigating ciliate protozoan systematics and/or ciliate cortical structure and morphogenesis. The technique is complicated, however, by both uncertainties arising from the need to count drops of reagents and subjective control of the staining intensity. I have resolved these complications by defining volumes of reagents rather than using drops and by defining a range of staining times. I also comment on various steps of the techniques. My techniques are simplified and refined to produce consistent, high quality staining results.     

What gives Bolt the edge—A.V. Hill knew it already!

The 100 m is the blue ribboned event of world athletics competitions, with the winner crowned as the fastest human on Earth. Currently that fastest human is Usain Bolt, who covers 100 m in 9.58 s, achieving an average velocity of 10.43 m s^?1. Bolt is a phenomenal athlete, but what is his trick? Using Hills model, relating muscle force and heat liberation to shortening velocity, we propose that Bolt is at an advantage in relative power development and biomechanical efficiency compared to his contemporaries.     

Phylogeny and the “polyphyletic-polychronic-polytopic” system of classification of angiosperms— A response to Fu De-Zhi

The historical development of the concepts of genealogy, phylogeny, mo nophyly and polyphyly is briefly reviewed. The different implications of the tw o most controversial terms in taxonomic and evolutionary literature, “monophyly " and “polyphyly", are