Sledování volnýeh aminokyselìn v cizosprášenýeh, samosprášenýeh a neopylenýelt pestícíchNicotiana alata
1961; Institute of Experimental Botany of the Czech Academy of Sciences; Volume: 3; Issue: 1 Linguagem: Inglês
10.1007/bf02933503
ISSN1573-8264
Autores Tópico(s)Plant Reproductive Biology
ResumoThe growth of pollen tubes evokes changes in the level of free amino-acids in the style. This has been demonstrated in the cases of alanine, valine, leucine—isoleucine, serine, threonine, γ-aminobutyric acid, asparagine, glutamic acid and proline. These changes take place mainly in the parts of the style where the pollen tubes are present. The most marked changes are an increase in the level of γ-aminobutyric acid and alanine and a decrease in glutamic acid. The intensity of these processes is much greater following compatible pollination than in the case of incompatible autogamy. On the assumption that the main course of γ-aminobutyric acid and alanine katabolism takes place by transamination with α-ketoglutaric acid, the basic nature of the above changes is explained as being due to a relative deficiency of the latter acid. Alongside a reduction in the level of sugars an accumulation of asparagine takes place in pollinated styles. The rise in its level is considerably more rapid in cross-pollinated than in self-pollinated styles. If accumulation of asparagine is a result of more intensive consumption of proteins during respiration when there is a scarcity of sugars, it follows from the above results as from previous work (TUPý 1961), that pollen tubes use substrates from the style tissues for respiration and that this process is limited in the case of incompatible inhibition. At the time when the pollen tubes are growing through the styles, the levels of γ-aminobutyric acid and alanine are already rising in the ovaries of pollinated flowers. This increase is quantitatively in direct ratio to the rate of pollen tube growth, which depends on the compatible or incompatible character of the pollination.
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