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Phenological and water-use patterns underlying maximum growing season length at the highest elevations: implications under climate change 总被引：1，自引：0，他引：1
Consequences of climate change on tree phenology are readily observable, but little is known about the variations in phenological sensitivity to drought between populations within a species. In this study, we compare the phenological sensitivity to temperature and water availability in Abies pinsapo Boiss., a drought-sensitive Mediterranean fir, across its altitudinal distribution gradient. Twig growth and needle fall were related to temperature, precipitation and plant water status on a daily scale. Stands located at the top edge of the distributional range showed the most favourable water balance, maximum growth rates and little summer defoliation. Towards higher elevations, the observed delay in budburst date due to lower spring temperatures was overcome by a stronger delay in growth cessation date due to the later onset of strong water-deficit conditions in the summer. This explains an extended growing season and the greatest mean growth at the highest elevation. Conversely, lower predawn xylem water potentials and early partial stomatal closure and growth cessation were found in low-elevation A. pinsapo trees. An earlier and higher summer peak of A. pinsapo litterfall was also observed at these water-limited sites. Our results illustrate the ecophysiological background of the ongoing altitudinal shifts reported for this relict tree species under current climatic conditions. 相似文献
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Cristina lvarez Noelia Gonzlez Victoria Luo Felisa Martínez Lydia Gil 《Reproduction in domestic animals》2019,54(Z4):94-97
The aim of this study was to test and compare two new components in extenders for freezing donkey semen: mare colostrum and jenny colostrum. Colostrum was obtained from four mares and four jennies right after the foal's birth. Ejaculates were collected from five fertile donkeys. Sperm samples were pooled, diluted and cryopreserved in three different experimental extender groups: lactose supplemented with egg yolk extender (20%) as the control group, lactose supplemented with jenny colostrum extender (20%), and lactose supplemented with mare colostrum extender (20%). After thawing, we evaluated the sperm motility by means of computer‐assisted analysis, viability by SYBR‐14 and propidium iodide (PI), membrane functional by HOS test and acrosome integrity by isothiocyanate conjugated with peanut agglutinin (FITC‐PNA) and PI. The results demonstrated that lactose–jenny colostrum extender displayed significantly higher values (p < .05) in nearly all parameters evaluated – Total Motility, Viability, HOS test, VCL, VSL, VAP, LIN, STR and WOB –, compared with mare colostrum and egg yolk extenders after thawing. In conclusion, the extender containing jenny colostrum used for donkey semen cryopreservation improved the donkey sperm quality after the freezing–thawing process. 相似文献
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In natural plant populations, leaf polyphenols show high intraspecific variation that occurs both temporally and spatially. Leaf phenolics may be induced by diverse ecological factors such as light, nitrogen availability or herbivory attack. Both light and nitrogen availability can show spatial structure in forested stands, meaning that they each have a high degree of autocorrelation, which can determine the appearance of spatial structure in leaf polyphenols. However, the availability of these resources may be drastically changed by forest disturbance, and little is known about the effect of forest disturbance on the spatial pattern and scale of leaf secondary compounds. We hypothesise that the spatial structure of leaf polyphenols in understory vegetation will disappear due to forest harvesting, because these compounds depend on light availability, yet it will remain unaltered for those compounds that either depend on the availability of other resources or are under major genetic control. The study was performed in young pedunculate oak (Quercus robur) populations growing either under a pine canopy (Pinus pinaster) stand or in a pine harvested stand in NW Spain. The spatial structures of green and senescent leaf polyphenols, tannins, non-tannin polyphenols and nitrogen were analysed in both stands using geostatistical analysis. The spatial structures observed for green and senescent leaf polyphenols and tannins in the forested stand disappeared in the harvested stand. However, non-tannin polyphenols, as well as nitrogen, showed spatial structure in both stands. Understanding these changes may be important for the successful recovery of native oak populations growing under pine forests in NW Spain, one of the priorities of the local government. Our results showed that changes in the concentration of leaf secondary compounds after disturbance may be accompanied by differences in their spatial properties, which may have important consequences for ecosystem function. 相似文献
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Summary The narrow genetic base of the cultivated potato is a severe constraint for potato breeding. Wild tuber-bearing species constitute
an important source of genes for resistance to diseases and pests as well as abiotic factors. Seven interspecific hybrid populations
were generated from crosses between diploidTuberosum clones and four wild species:Solanum berthaultii, S. gourlayi, S. tarijense andS. vernei, and evaluated in a field experiment in Burgos (Spain) as a way to broaden the genetic base of the cultivated potato. Good
tuberization ability and great variability for yield within the different families were detected. Hybridization with the wild
species resulted in high levels of PVY resistance inS. berthaultii andS. vernei hybrids and a large increase of dry matter content in all populations except theS. berthaultii hybrids. 相似文献
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Carbonaceous material obtained from industrial sewage sludge and Na-zeolitic tuff were used to adsorb cadmium from aqueous solutions in column systems. The Bohart, Thomas, Yoon–Nelson, and mass transfer models were successfully used to fit the adsorption data at different depths, and the constant rates were evaluated. The parameters such as breakthrough and saturation times, bed volumes, kinetic constants, adsorption capacities, and adsorbent usage rates (AUR) were determined. The results show that the breakthrough time increases proportionally with increasing bed height. The adsorption capacity for cadmium for Na-zeolitic tuff was higher than carbonaceous material. The results indicated that the Na-zeolitic tuff is a good adsorbent for cadmium removal. 相似文献
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Nutrient resorption is an important mechanism for nutrient preservation in plants. Variations in nutrient availability can interfere with resorption-regulating mechanisms. Disturbances (such as forest harvest) leading to a loss of organic matter and nutrients in the soil could therefore determine important changes in resorption rates. This paper examines the effect of pine forest harvest on N and P resorption in young common oaks (Quercus robur) living under pine cover over a 4-year study period. The results obtained show a decrease in N-NH4+ concentration in the soil in the 2 years following the forest harvest process. Forest harvest did not affect the edaphic concentration of NO3− and PO43−, which presented relatively low values in both areas. Foliar concentration of N was significantly lower in the areas affected by forest harvest, whereas the differences in the foliar concentration of P varied each year. The mean foliar N/P ratio was greater in the non-harvested areas, but showed possible limitation by P in both harvested and non-harvested sites. 相似文献
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Milaja Nyknen Marie Louis Eileen Dillane Eric Alfonsi Simon Berrow Joanne O'Brien Andrew Brownlow Pablo Covelo Willy Dabin Rob Deaville Renaud de Stephanis Franois Gally Pauline Gauffier Simon N. Ingram Tamara Lucas Luca Mirimin Rod Penrose Emer Rogan Mnica A. Silva Benoit Simon‐Bouhet Oscar E. Gaggiotti 《水产资源保护:海洋与淡水生态系统》2019,29(Z1):197-211