Avtor/Urednik		Bavcon, Jože; Druškovič, Blanka; Gogala, Nada
Naslov		Effects of UV-B radiation on growth and mitotic activity in the norway spruce (Picea abies (L.) Karst.)
Prevedeni naslov		Vpliv UV-B sevanja na rast in mitotsko aktivnost pri smreki (Picea abies (L.) Karst.)
Tip		članek
Vir		Acta Biol Slov
Vol. in št.		Letnik 42, št. 2
Leto izdaje		1999
Obseg		str. 9-16
Jezik		eng
Abstrakt		Effects on certain growth parameters and mitotic activity were studied on Norway spruce seedlings of three and a half years exposed to continuous UV-B radiation. We wanted to test the hypothesis that UV-B radiation is one of the primary factors influencing growth and damaging young spruce seedlings at higher altitudes. The spruce seedling grew in clay pots placed in open greenhouses. Osram Ultravitalux 300 W elongated light bulbs were used as a source of radiation. In the first open greenhouse, we used a control unit with natural UV-B radiation only, subjected to the considerable oscillations depending on outdoor climatic conditions. The measured daily does between 9 a.m. and 5 p.m. amounted to 11.7+- 5.2 kJ/m2. The second and third greenhouses with artificial radiation sources provided doses of 21.24 +- 3.5 kJ/m2 and 31.9 +- 2.5 kJ/m2, respectively. After three and a half years of exposure to radiation, spruce seedlings showed the sensitivity to UV-B radiation. In comparison with the control group, they exhibited poorer growth of shoots and needles. The control specimens were dark green and were of extreme vitality, while the treated plants were yellowish-green with chloroses and necroses in the youngest needles. A significant decrease in the mitotic activity of the cells of the root meristem was detected as well.
Izvleček		Na sejancih smreke, izpostavljenih stalnemu viru UV-B sevanja, smo v lončnem poizkusu ugotavljali vpliv na nekatere rastne parametre in mitotsko aktivnost. Želeli smo preveriti hipotezo ali je povečano ultravijolično sevanje eden izmed primarnih dejavnikov poškodb v višjih legah. Za vir sevanja smo uporabili osram ultravitaluks 300 W glivaste žarniste. V kontrolnem plastenjaku brez umetnega vira UV-B sevanja smo izmerili dnevno dozo med 9 in 17 uro 11.7 +- 5.2 kJ/m2. V plastenjaku z umetnim virom sevanja je na razdalji sejank izmerjena doza 21.24 +- 3.5 kJ/m2, v drugem z nekoliko močnejšim sevanjem pa 31.9 +- 2.5 kJ/m2. Po treh letih in pol obsevanja smo ugotovili, da so smrekove sejanke občutljive na UV-B sevanje. Pri sejankah se je v prikerjavi s kontrolo signifikantno zmanjšala rast poganjka in iglic, pojavile so se kloroze in nekroze iglic. Prav tako pa se je signifikantno zmanjšala tudi mitotska aktivnost celic koreninskega meristema.
Deskriptorji		MITOTIC INDEX TREES ULTRAVIOLET RAYS SEEDS