[Inheritance and expression of gametophyte gene Adh-P causing modification of alcohol dehydrogenase in pollen grains of the beet (Beta vulgaris L.)]. / Nasledovanie i ékspressiia gametofitnogo gena Adh-P vyzyvaiushchego modifikatsiiu alkogol'degidrogenazy v pyl'tsevykh zernakh svekly (Beta vulgaris L.).

An additional alcohol dehydrogenase (ADH) activity zone denoted ADH-P ("pollen") has a slightly lower mobility than the major protein ADH1 (the product of structural locus Adh1). This zone is detected in maturing and mature pollen grains and has not been found in any other tissue. ADH-P is detected by electrophoresis in a neutral medium (at pH 7.0-7.2). In an alkaline medium (pH > 8), protein ADH-P is completely inactivated, whereas protein ADH1 retains its activity. ADH-P is a modified variant of the major protein ADH1. Both alleles of the main structural gene (Adh1-F and Adh1-S) undergo modification. The pollen of an FS heterozygote has two variants of the modified enzyme: ADH-PS and ADH-PF. Analysis of segregation in F2 offsprings and test crosses has confirmed that this character is controlled by the only gene Adh-P with allelic variants Adh-P+ (the presence of the modified ADH protein in the pollen) and Adh-P- (the normal protein). Allele Adh-P+ is transmitted through female gametes at a normal frequency (about 1) and through male gametes at a decreased frequency (0.2-0.6), the mean frequency being about 0.4. The frequency of the transmission of allele Adh-P+ through male gametes depends on the genotype of the female parent and the conditions of pollination. Cytoembryological study of microsporogenesis in the Adh-P+/Adh-P- heterozygotes demonstrated an absence of any disturbances in the formation of microspores and pollen grains. Some differences in the formation of pollen tubes on an artificial medium have been observed. It is assumed that the differences between the Adh-P+ and Adh-P- microgametophytes manifest themselves at the progamic phase of fertilization. The possible mechanisms of the formation of the modified ADH-P protein are discussed in connection with the differential activity of genes in the microgametophytes of angiosperms.

[Restorative morphogenesis in vitro of the annual Medicago species in presence of benzylaminopurine]. / Vosstanovitel'nyi morfogenez in vitro u odnoletnei liutserny pod vliianiem benzilaminopurina.

Four annual medick species (Medicago orbicularis (L.) All., M. rigidula (L.) Desr., M. scutellata (L.) Miller, and M. rugosa Desr.) were used as model objects for studying the spectrum of morphogenetic reactions in vitro. The seeds were incubated on nutrient media with benzylaminopurine at different concentrations until germination and, thereafter, the explants of seedlings were cultivated in order to obtain primary calluses and morphogenetic structures. Normal and abnormal (with reduced root and/or apex) seedlings were cultivated in the presence of benzylaminopurine. Further cultivation of explants from the seedlings of both types showed a considerable intra- and interspecific polymorphism by the capacity for callusogenesis, frequency of primary restorative reactions, and pattern of microreproduction in vitro. In the control (the seeds were incubated on a hormone-free medium), no cases of microreproduction by way of organogenesis or somatic embryogenesis were observed. In all experimental variants, the restorative reactions preceded microreproduction in vitro.