Gas exchange and photosynthetic pigment content in latitudinal ecotypes of the Siberian stone pine ex situ

Abstract

Carbon dioxide gas exchange and the pigment content of the photosynthetic apparatus of the Siberian stone pine Pinus sibirica Du Tour ecotypes vegetative scion from the West Siberian latitudinal transect grown on the geographical grafting plantation in the south of the Tomsk Region were studied. The latitudinal transect was represented by three ecotypes: Tomsk, the southern border of the range; Strezhevoy, middle taiga; Urengoy, northern border of the range. The age of the grafted trees was 20 years. It was shown that the photosynthesis intensity did not differ between ecotypes significantly, respiratory activity increased significantly from south to north, and the differences were 79 % between marginal ecotypes. The results of the experiment revealed that the respiration / photosynthesis ratio was twice as high in northern than in southern ecotype, which indicates a lower plant productivity of the northern ecotype. The results of measuring stomatal conductance and the intercellular CO2 concentration showed that these values did not differ between ecotypes significantly. Research has revealed the tendency towards the decrease of green pigment contents in the middle taiga ecotype and the significant decrease those in the northern ecotype. The Chl a/b ratio increased from south to north from 2.7 to 3.2. On the contrary, the Chl/Car ratio decreased between marginal ecotypes from 6.2 to 5.7 due to the reduce of green pigment contents in the northern ecotype. The obtained data indicate the photosynthetic acclimation when ecotypes were moved to the warmer climate. The photosynthetic pigment synthesis and respiratory activity are largely regulated by hereditary factors (the ecotype origin).

Keywords

• pinus sibirica du tour
• acclimation
• photosynthesis
• respiration
• chlorophylls
• carotenoids