Bulletin of Science and Practice

Number 1, 2021

10-18
Unusual Order of Chromosome Arrangement Location in Late Prophase - Early Prometaphase of Mitosis in Haploid Maize Plant Obtained With the Use of Mutation ig

Authors: Yudina R., Levites E.

Abstract

View in PDF

Number of views: 123

Despite the huge amount of works devoted to the study of mitotic division, there is still a lot of unclear in its mechanisms. For example, insufficient attention has been paid to the processes of cell division in plant forms of different ploidy levels. The literature contains only fragmentary data on haploids in lower plants. This does not allow making any generalizations regarding mitosis in haploids of higher plants. This article presents the results of a cytological study of mitotically dividing cells of haploid maize plants. The article demonstrates the effectiveness of the well-known Chase method, based on the use of genetic markers and the ig mutation (indeterminate gametophyte) for obtaining and detecting haploids. An effective modification of a simple method of acetocarmine staining of cytological preparations is described. An essential result obtained is, in our opinion, the detection of a very brief moment in the state of chromosomes in a dividing cell of a haploid maize plant. This moment is characterized by the fact that the chromatids have already separated and turned into independent chromosomes, but have not yet begun their movement under the action of kinetochore microtubules. It is this feature that made it possible to designate this state as late prophase – early prometaphase of mitosis. An equally important feature of the detected moment is the unusual ordered arrangement of chromosomes, which lie parallel to each other close to each other along their entire length with the centromeres located on one line, which can be considered the equator of the fission spindle. The revealed fact allows us to assume that an essential role in the formation of such an arrangement of chromosomes is played by the bond of chromosomes with the equator of the nuclear membrane and their subsequent connection with the equator of the fission spindle.

19-32
Polyvariance of Shoot Morphogenesis in Clones of Salix triandra (Salicaceae) Against the Background of the Periodicity of Rainstorms

Authors: Afonin A.

Abstract

View in PDF

Number of views: 106

The article substantiates the need to study the development of one-year saplings from cuttings of almond willow (Salix triandra). Purpose of research: identification and analysis of seasonal dynamics of daily growth of shoots in S. triandra clones against the background of excessive atmospheric moisture in the form of three showers in 2020. Material and methods. Research methods: selection, structural-morphological, chronobiological. Object of research: model inbred-clone one-year population of S. triandra. The number of clones is 7; the recurrence is 6-fold. Material: growing annual shoots on one-year saplings; each sapling was formed into a single shoot. Results. Under experimental conditions, the rooting capacity of cuttings was 100%. Dimorphic root systems were formed on the mother cuttings of the excavated seedlings. The annual growth of the strongest shoots was 175 ... 215 cm. The daily growth in shoots reached peak values by June 10: the average daily growth was 3.6 cm/day, the maximum — 4.4 ... 4.9 cm/day. After June 10, the daily growth rate decreased unevenly until the end of the growing season. Some shoots completed growth before the beginning of August, and some continued growth until the middle of August. The cyclical nature of the seasonal dynamics of daily growth in the form of three peaks separated by two dips is established. The third peak is formed after the third rainstorm. Discussion and conclusions. Cyclical seasonal dynamics of daily growth of shoots is characterized by a high degree of synchronization of growth processes. Probably, all the shoots are affected by some powerful pulse synchronizer of unknown nature. It is possible that periodic showers may have a modifying effect on the mechanisms that regulate growth processes. The temporal discreteness of shoot morphogenesis is due to the full or partial realization of the seasonal cycle of shoot development. The duration of growth is due to interclonal and intraclonal differences. Probably, the duration of morphogenesis is controlled by both genetic and epigenetic factors.

33-48
Geoactive Zones and the Structure of Plant Communities in Connection With New Discoveries in Space Geology

Authors: Rogozin M., Mikhalev V., Rybalchenko A.

Abstract

View in PDF

Number of views: 122

The purpose of the work is to find out how plants react to such zones and whether their phyto-indication is possible. Two territories of the Perm territory were studied: the Vishersky nature reserve and forests near Perm. The research methodology included lineament and geo-structurometric analysis of space images and special maps using ring structures discovered on the Earth’s surface by Yu. I. Fivensky, as well as phyto- and bioindication of SGA-zones. It was found that in the forests near Perm favorable zones of such zones occupy 1.44% of the territory and within their limits the safety of common pine (Pinus sylvestris L.) is 29–42 times higher. Phytoindication of SGA-zones of 1.0 and 3.0 m by common pine was shown in the zones of influence of these zones: 0-18 cm — the radius of inhibition with the absence of trees; 19–29 cm — the depression zone with small trees; 30–48 cm — the comfort zone with medium and large trees. Two types of networks formed by zones of 1.0 and 8.0 m in size near Perm (on the plain) and in the reserve (in the mountains) were compared. In the mountains, with high geodynamic activity of territories, the networks are oriented in one direction, while on the plain their orientation is misaligned by 30°. In the reserve, large trees of Siberian spruce (Picea obovata Ledeb.) were located on SGA-zones of 1.0 and 8.0 m, and trees of Siberian pine (Pinus sibirica Du Tour) — on zones 1.0 and 3.0 m in combination with zones 16, 32 and 55 m. In the sub-Holz zone, ring structures of perennial plants were also found on the first two types of zones. In addition, along the edges of the swamps, chains of trees were found whose direction coincides with ring faults, and the chains themselves are similar to the structure of SGA-zones networks, and this fractality requires field verification. The hypothesis recharge of plants within geoactive zones is proposed, which also explains the successful growth of trees on rocks, where the amount of available soil is minimal.