Abstract
Stem respiration of two forms of Betula pendula Roth [Silver birch ( B. pendula var. pendula ) and Karelian birch ( B. pendula var. carelica )] was investigated. 5-6-years old trees and 2-3-years old seedlings, grown in pots, were studied. Among objects of Karelian birch, there were specimens both without visible deviations from normal growth and with structural anomalies of stems. Along with the relationship with environmental factors (mainly temperature), stem respiration rate was strongly related with cambial activity and stem width growth. Before cambial growth (in June) mean respiration rates of twigs and stems in seedlings with diameters 10-14 mm were 5,3 and 4,6 μmol·m -2 ·s -1 in Silver birch and Karelian birch respectively, during cambial growth (late June – first half of August) – 12,3 and 17,6 μ mol·m -2 ·s -1 , and during period of growth attenuation (second half of August – early September) – 2,6 and 3,1 μmol·m -2 ·s -1 . Maximal respiration rates (20 μmol·m -2 ·s -1 and 28 μmol·m -2 ·s -1 for Silver birch and Karelian birch respectively) registered in late July, were higher (in absolute value) than net CO 2 gas exchange of leaves. In about 30% of measurements, respiration rate in Karelian birch was more than two times higher than in Silver birch. Higher respiration rate in Karelian birch than in Silver birch is mostly related with higher metabolic activity in cambial zone and more amount of live respiring tissues per unit of a stem length in stems of the same width in this two forms of birch. Measurements have shown that thickness and volume of the bark in Karelian birch were higher by 16-20% than in Silver birch. There were no significant differences in stem respiration of 6-years old Karelian birch trees, which already had visible thickenings of stems, and seedlings without visible signs of structural anomalies of stems. In rare cases there were higher stem respiration rate in Silver birch than in Karelian birch. The causes of this phenomenon are analyzed.
Highlights
В ходе вегетации изучали дыхание стволов и ветвей двух форм деревьев Betula pendula Roth: обычной березы повислой (B. pendula var. pendula) и карельской березы (B. pendula var. carelica)
Stem respiration was investigated in two forms of Betula pendula Roth [Silver birch (B. pendula var. pendula) and Karelian birch (B. pendula var. carelica)]
Higher respiration rate in Karelian birch in comparison with Silver birch is mostly related to higher metabolic activity in the cambial zone and higher amount of living respiring tissues per unit of stem length in stems of the same width in the two birch forms
Summary
В ходе вегетации изучали дыхание стволов и ветвей двух форм деревьев Betula pendula Roth: обычной березы повислой (B. pendula var. pendula) и карельской березы (B. pendula var. carelica). В ходе вегетации изучали дыхание стволов и ветвей двух форм деревьев Betula pendula Roth: обычной березы повислой Наряду с зависимостью от внешних факторов среды (в основном температуры) наблюдалась тесная связь дыхания с деятельностью камбия и ростом ствола в толщину. Наряду с зависимостью от внешних факторов среды (в основном температуры) наблюдается тесная связь дыхания с деятельностью камбия и ростом ствола в толщину [Negisi, 1981; Забуга, Забуга, 2005; Татаринов и др., 2011]. Поскольку у БК наряду со значительным увеличением объемов коры имеются и другие пути утилизации избыточных ассимилятов [Новицкая, 2008], энергетика процессов в прикамбиальной зоне может существенно отличаться по сравнению с БП, что отразится на дыхании тканей ствола и ветвей. Представляет интерес исследовать этот процесс у карельской березы в сравнении с березой повислой на разных этапах вегетации, влияние на него температуры, дефицита водяного пара в воздухе и других факторов внешней среды
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