DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 9-10/1965 str. 39 <-- 39 --> PDF |
papira. U momentu otvaranja ženskih cvasti, pomoću specijalnih pumpica, u kesu se ubrizgava željeni polen, a posle zatvaranja ženskih cvasti kese se skidaju. Ukoliko se pre početka izolacije ne izvrši emaskulaeija ženskih šišarica kod dvopolnih cvasti belog bora, opasnost od samooplodnje nije odstranjena, pa sve to može da poremeti ili sasvim da promaši postavljeni zadatak hibridizacije. Radi toga za hibridizaciju je potrebno da se prethodno dobro prouči biologija cvetanja svake pojedine vrste i posebno pojedinog drveta, jer je ona još uvek nedovoljno poznata i nije uvek ista. Od tog poznavanja biologije cvetanja upravo i zavisi celokupni uspeh radova na oplemenjivanju. OCCURRENCE OF BISEXUAL INFLORESCENCES IN SCOTS PINE (Pinus sylvestris L.) Summary Scots Pine (Pinus silvestris L.) is a monoecious plant with unisexual reproductive organs. In nature, however, the reproductive organs need not always be situated on different annual shoots. On Mount Kajmakcalan we had the opportunity to discover bisexual inflorescences in two trees of Scots Pine. On the same tree — besides the bisexual inflorescences — there were growing on separated annual shoots separately male catkins and separately female catkins. In bisexual inflorescences growing on one and the same annual shoot, i. e. on the same axis the male catkins were situated on the lower part and at the top the female catkins. The bisexuality in Scots Pine most probably represents a repetition (renewal) of a very ancient arrangement of female and male catkins. The existence of bisexual inflorescences has a very imoprtant scientific and practical significance. In order to avoid self-fertilization before the beginning of isolation of female catkins for artificial hybridization, it is necessary to remove the male flowers. |