| 1. |
- Gräns, Daniel
(författare)
-
Genetic Variation in Response to Herbicide and Fertilization Treatments for Growth and Form Traits in Loblolly Pine
- 2016
-
Ingår i: Forest Science. - : Oxford University Press (OUP). - 0015-749X. ; 62, s. 633-640
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of imposed silvicultural treatments and genetics on growth and form traits were investigated in a 15-year-old loblolly pine (Pinus taeda L.) trial in southwestern Georgia, USA. The trial consisted of four treatment combinations and 25 open-pollinated first- and second-generation families. Average individual-tree stem volume ranged from 185.2 dm(3) in the combined fertilization and herbicide plots to 91.2 dm(3) in the control plots. Variation among treatment combinations was significant for height, volume, sweep, and forking defect but was not significant for branch angle and fusiform rust disease incidence (caused by the fungus Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). Family effects were significant for all traits across treatments. Individual-tree heritability values ranged from 0.10 (stem sweep) to 0.39 (branch angle). Corresponding family-mean heritability values had a range of 0.60 (stem sweep) to 0.90 (branch angle). Genetic correlations between growth (height and volume) and other traits (rust, branch angle, stem forking, and stem sweep) were low and not significant. The lack of important culture x genetics interactions in the study indicates a low risk of losing value due to suboptimal matching between genetic material and silvicultural prescriptions.
|
|
| 2. |
- Morgenroth, Daniel, et al.
(författare)
-
Hemodynamic responses to warming in euryhaline rainbow trout: implications of the osmo-respiratory compromise
- 2019
-
Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 222:17
-
Tidskriftsartikel (refereegranskat)abstract
- In seawater, rainbow trout (Oncorhynchus mykiss) drink and absorb water through the gastrointestinal tract to compensate for water passively lost to the hyperosmotic environment. Concomitantly, they exhibit elevated cardiac output and a doubling of gastrointestinal blood flow to provide additional O-2 to the gut and increase convective flux of absorbed ions and water. Yet, it is unknown how warming waters, which elevate tissue O-2 demand and the rate of diffusion of ions and water across the gills (i.e. the osmo-respiratory compromise), affects these processes. We measured cardiovascular and blood variables of rainbow trout acclimated to freshwater and seawater during acute warming from 11 to 17 degrees C. Relative to freshwater-acclimated trout, cardiac output was 34% and 55% higher in seawater-acclimated trout at 11 and 17 degrees C, respectively, which allowed them to increase gastrointestinal blood flow significantly more during warming (increases of 75% in seawater vs. 31% in freshwater). These adjustments likely served to mitigate the impact of warming on osmotic balance, as changes in ionic and osmotic blood composition were minor. Furthermore, seawater-acclimated trout seemingly had a lower tissue O-2 extraction, explaining why trout acclimated to freshwater and seawater often exhibit similar metabolic rates, despite a higher cardiac output in seawater. Our results highlight a novel role of gastrointestinal blood perfusion in the osmo-respiratory compromise in fish, and improve our understanding of the physiological changes euryhaline fishes must undergo when faced with interacting environmental challenges such as transient warming events.
|
|
| 3. |
- Sundell, Erika, et al.
(författare)
-
Seawater acclimation affects cardiac output and adrenergic control of blood pressure in rainbow trout (Oncorhynchus mykiss)-implications for salinity variations now and in the future.
- 2018
-
Ingår i: Conservation physiology. - : Oxford University Press (OUP). - 2051-1434. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Greater salinity variations resulting from ongoing climate change requires consideration in conservation management as this may impact on the performance of aquatic organisms. Euryhaline fish exhibit osmoregulatory flexibility and can exploit a wide range of salinities. In seawater (SW), they drink and absorb water in the intestine, which is associated with increased gastrointestinal blood flow. Yet, detailed information on other cardiovascular changes and their control across salinities is scant. Such knowledge is fundamental to understand how fish are affected during migrations between environments with different salinities, as well as by increased future salinity variability. We used rainbow trout (Oncorhynchus mykiss) as a euryhaline model species and determined dorsal aortic blood pressure, cardiac output and systemic vascular resistance in vivo after chronic freshwater-or SW-acclimation. We also assessed α-adrenergic control of blood pressure using pharmacological tools. Dorsal aortic blood pressure and systemic vascular resistance were reduced, whereas cardiac output increased in SW. α-Adrenergic stimulation with phenylephrine caused similar dose-dependent increases in resistance and pressure across salinities, indicating unaltered α-adrenoceptor sensitivity. α-Adrenergic blockade with prazosin decreased resistance and pressure across salinities, but the absolute reduction in resistance was smaller in SW. Yet, both pressure and resistance after prazosin remained consistently lower in SW. This shows that SW-acclimation lowers systemic resistance through reduced vascular α-adrenergic tone, along with other unknown vasodilating factors. The marked changes in adrenergic regulation of the vasculature across salinities discovered here may have implications for cardiovascular and aerobic performance of fishes, with possible impacts on fitness-related traits like digestion and exercise capacity. Moreover, the evolution of more complex circulatory control systems in teleost fishes compared with elasmobranchs and cyclostomes may have been an important factor in the evolution of euryhalinity, and may provide euryhaline teleosts with competitive advantages in more variable salinity environments of the future.
|
|
| 4. |
- Wallin, Elisabeth, et al.
(författare)
-
Evaluating methods for storability assessment and determination of vitality status of container grown Norway spruce transplants after frozen storage
- 2019
-
Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 34:6, s. 417-426
-
Tidskriftsartikel (refereegranskat)abstract
- Autumn sown small seedlings for later transplanting into large containers have been introduced in Swedish forest tree nurseries. Containerized transplants of Norway spruce (Picea abies (L.) Karst.) from three Swedish nurseries were frozen stored during the autumn of 2014 to find out storability and post-storage vitality. Seedling storability was determined by measuring electrolyte leakage after freezing shoots to −25°C (SELdiff−25), by measurements of dry matter content (DMC) of seedling shoots and by the commercial molecular test ColdNSure™. Vitality of seedlings after storage was determined by measuring the leakage of electrolytes from shoots (SEL), and seedlings were also tested in regrowth tests. All three methods for storability assessment gave similar predictions, except in one case where DMC showed “not storable” for successfully stored seedlings. Our results indicated that young transplants can be successfully short term stored before reaching the target levels for safe long-term storage of conventional seedlings. Early storage of young transplants resulted in low post-storage survival and vitality expressed as root growth capacity and shoot electrolyte leakage (SEL). A prolonged duration in storage generally resulted in lower survival as well as lower root growth capacity and higher levels of SEL, especially for seedlings stored at earlier dates.
|
|
| 5. |
- Wallin, Elisabeth, et al.
(författare)
-
Short-day photoperiods affect expression of genes related to dormancy and freezing tolerance in Norway spruce seedlings
- 2017
-
Ingår i: Annals of Forest Science. - : Springer France. - 1286-4560 .- 1297-966X. ; 74:3
-
Tidskriftsartikel (refereegranskat)abstract
- Key message: Gene expression analysis showed that prolonged short day (SD) treatment deepened dormancy and stimulated development of freezing tolerance of Picea abies seedlings. Prolonged SD treatment also caused later appearance of visible buds in autumn, reduced risks for reflushing, and promoted earlier spring bud break.Context: Short day (SD) treatment of seedlings is a common practice in boreal forest tree nurseries to regulate shoot growth and prepare the seedlings for autumn planting or frozen storage. Aims The aim of this study was to examine responses of Norway spruce (Picea abies (L.) Karst.) to a range of SD treatments of different length and evaluate gene expression related to dormancy induction and development of freezing tolerance.Methods: The seedlings were SD treated for 11 h a day during 7, 14, 21, or 28 days. Molecular tests were performed, and the expression profiles of dormancy and freezing tolerance- related genes were analyzed as well as determination of shoot growth, bud set, bud size, reflushing, dry matter content, and timing of spring bud break.Results: The 7-day SD treatment was as effective as longer SD treatments in terminating apical shoot growth. However, short (7 days) SD treatment resulted in later activation of dormancy-related genes and of genes related to freezing tolerance compared to the longer treatments which had an impact on seedling phenology.Conclusion: Gene expression analysis indicated an effective stimulus of dormancy-related genes when the SD treatment is prolonged for at least 1-2 weeks after shoot elongation has terminated and that seedlings thereafter are exposed to ambient outdoor climate conditions.
|
|
