Dehydrin stress proteins in Pinus sylvestris L. needles under conditions of extreme climate of Yakutia.

This is the first study to investigate stress proteins dehydrins with the use of specific antibodies in the Scots pine (Pinus sylvestris L.) needles and their changes in the annual cycle under extreme climate of Yakutia. No pronounced polymorphism of major dehydrins (14-15 and 66 kDa) has been found during the winter dormancy period of P. sylvestris. A clear correlation between the seasonal variations in dehydrins and changes in the water content in needles was revealed. Consistently high levels of dehydrins was retained throughout the period of low negative temperatures. It is assumed that dehydrins can participate in the formation of P. sylvestris L. resistance to the permafrost conditions.

Comparison of the photosynthetic capacity of Siberian and Japanese birch seedlings grown in elevated CO(2) and temperature.

The effects of increased CO(2) and temperature on the photosynthetic capacity of Siberian white birch and Japanese white birch (Betula platyphylla Sukatch. and B. platyphylla Sukatch. var. japonica Hara) were measured. Birch seedlings were raised with a CO(2) partial pressure of 36 +/- 0.3 Pa (i.e., ambient) or 70 +/- 0.6 Pa at day/night temperatures of either 30/16 degrees C or 26/12 degrees C. Siberian birch leaves were smaller and thicker than Japanese birch leaves. Water use efficiency and nitrogen use efficiency of Siberian birch grown in the CO(2)-enriched air were higher than those of Japanese birch. Both species showed a physiological adjustment to the growth CO(2) partial pressure. Carboxylation efficiency and quantum yield of both species grown in CO(2)-enriched air were lower than those of seedlings grown in ambient CO(2). The adaptation of Siberian and Japanese birch to elevated CO(2) and temperature are discussed in relation to predicted climate change.