Waterlogging under simulated late-winter conditions had little impact on the physiology and growth of Norway spruce seedlings

Context

Waterlogging is predicted to become more common in boreal forests during winter and early spring with climate change. So far, little is known about the waterlogging tolerance of boreal tree species during their winter dormancy.

Aim

The aim was to quantify the degree of waterlogging tolerance of 1-year-old dormant Norway spruce (Picea abies (L.) Karst.) seedlings.

Methods

The seedlings were exposed to waterlogging in a growth chamber at temperature of 2 °C for 4 weeks and then allowed to recover for 6 weeks during the growth stage. Shoot and root responses were monitored by physiological and growth measurements.

Results

No effect was found in the seedling biomass, but root mortality increased slightly during the early growth stage following waterlogging. The water potential of the needles became less negative at the end of the waterlogging and the early growth stage. The ratio of apoplastic to symplastic electrical resistance (R _e/R _i) of the needles was lower after waterlogging, indicating changes in the proportions of symplastic and apoplastic space. No differences were found between the treatments in the dark-acclimated chlorophyll fluorescence (F _v/F _m) of the needles. Slightly greater accumulation of starch and temporary reductions of some mineral nutrients in needles were found after waterlogging.

Conclusions

We conclude that in late winter and early spring, Norway spruce seedlings potentially tolerate short periods of waterlogging.     

Analysis of Circulating Immune Complexes in the Serum of Clinically Healthy Horses

The aim of this study was to determine the level of circulating immune complexes (CIC) in equine serum and the electrophoretic properties of the protein fraction thereof. The study was carried out using 42 clinically healthy breeding horses of noble half-blood. The average extinction value of CIC's in equine serum was E450 nm = 0.278 ± 0.09 nm. Generally, 23 protein fractions were identified in the molecular mass range between 294 and 25 kDa. Eight fractions whose molecular masses were 137, 72, 65, 52, 42, 32, 28, and 26 kDa, respectively, appeared in all analyzed samples. In 20 of the analyzed serum an additional nine protein fractions whose molecular masses were 260, 110, 84, 78, 67, 62, 57, 45, and 39 kDa, respectively, were identified. Circulating immune complexes are a source of information about immunologic processes that take place in mammals. Determining the average values of CIC levels and identifying the electrophoretic profile of proteins in clinically healthy horses could be useful in research and diagnostics.