scholarly journals COMMUNICATION SYSTEMS OF TOPOLS IN COMMUNICATION WITH SYSTEMS OF THEIR REPRODUCTION

Author(s):  
Aleksey Sivolapov ◽  
Vladimir Sivolapov

We consider poplar selection systems in connection with their reproduction systems. Poplar is a model object on which it is possible to test all known systems for the selection of woody plants. Positive selection and synthetic selection methods (hybridization, mutagenesis, polyploidy, genetic engineering, biotechnology) effectively “work” on poplar. Poplar is propagated by seed, vegetative and in vitro biotechnology. Amphimixis or seed propagation of poplar is used to create hybrid seed plantations, for example white poplar × aspen. In natural poplar populations, spontaneous hybridization occurs, leading to the emergence of new species. The ability to vegetatively propagate poplar successfully solves the problem of plus breeding: selected best biotypes are propagated by in vitro grafting, cuttings or regenerants, and plantation cultures are created. Synthetic breeding methods: hybridization is widely used on poplar; dozens of poplar hybrids for forest crops and landscaping have been obtained; Induced mutants and polyploids are obtained. Breeders get their first genetically modified forms using genetic engineering. By microcloning, economically valuable individuals are propagated and regenerants are used to create forest crops and landscaping.

2013 ◽  
Vol 19 (1) ◽  
pp. 63-68
Author(s):  
Ki-Won Lee ◽  
Jin Young Moon ◽  
Hee Chung Ji ◽  
Gi Jun Choi ◽  
Ki-Yong Kim ◽  
...  

1962 ◽  
Author(s):  
John Coules ◽  
George Ganem ◽  
William H. Sumby

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
R Bertóti ◽  
Á Alberti ◽  
A Böszörményi ◽  
R Könye ◽  
T Horváth ◽  
...  

The results of scientific research are presented, which made it possible to develop less labor-intensive methods for selecting flax plants to grow original (updated) seeds. Studies have shown that a positive selection of tall plants of flax, compared with the accepted counterpart (control), increased seed yield 1.7-1.9 times. Moreover, plant homogeneity according to the main characteristics (height and fiber content in the stem) characterizing the varietal quality of grown seeds turned out to be at the control level. A negative selection, involving the removal of atypical plants, provided an increase in the output volume of seeds compared to the control by 3.9-4.1 times. This selection method did not reduce the varietal quality of seed material compared to the accepted analogue. With both selection methods, after combining typical plants, seeds with the same high germination rates were obtained (96-99 %). The breeding efficiency of the grown flax seeds using narrow-row sowing methods is shown. Studies have established that narrow-row sowing of seeds with a row-spacing of 7.5 and 6.25 cm compared with sowing by a wide-row method significantly increased their yield by 2.8-3.0 and 2.3-3.0 kg / ha, respectively. The greatest influence on the formation of seed yield in narrow-row sowing (6.25 cm) was exerted by the method of sowing, the part of which was 76.1 %. As the length of seed propagation of flax in creased (up to the uterine elite 2 years) in narrow-row sowing (6.25 cm) compared to broad-row, there was no decrease in quality indicators - germination and seed strength.


2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.


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