Since 1947 （Addy） [1, 2], marine biologists have conducted experiments in order to re-establish meadows using various methods of transplant. A 27-month experiment of germinating and growing Posidonia oceanica （L.）...Since 1947 （Addy） [1, 2], marine biologists have conducted experiments in order to re-establish meadows using various methods of transplant. A 27-month experiment of germinating and growing Posidonia oceanica （L.） Delile seeds was carried out in two areas near Piombino in the Leghorn Province （Italy）. Seeds in direct contact with the sea bottom were taken from other seaside areas. The leaf growth and the percentage of well-developed plants in the study areas were calculated. The results confirm that this method appears to be a good re-establishment technique despite the problems associated with finding a large number of seeds anywhere along Mediterranean coasts.展开更多
Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge...Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge is important since drought-adapted plants exhibit varied mechanisms of survival that may contribute to species coexistence.Methods We tested the responses of eight drought-adapted plants,a mix of graminoids,shrubs and forbs to three summer precipitation scenarios(1.3,2.6 and 3.9 cm per month)in a common garden experiment in the Great Basin(Owens Valley,California).Changes in mineral nutrient uptake(carbon,nitrogen,phosphorus,potassium,calcium,magnesium,manganese,copper,boron,zinc,iron and sodium)and gas exchange parameters(photosynthetic rate and stomatal conductance)were investigated in the studied species.Important Findings Two graminoids(Sporobolus airoides and Leymus triticoides)and one salt tolerant shrub species(Atriplex confertifolia)responded to increased water availability with increases in photosynthetic rate and/or stomatal conductance.There was a significant correlation between water availability and uptake of nutrients for five out of eight species.Artemisia tridentata,with higher rates of photosynthesis,contained greater amounts of potassium,copper and boron,while Juncus arcticus,with higher rates of photosynthesis,contained greater amounts of magnesium and iron,and less sodium.Juncus arcticus and three salt-adapted species(A.confertifolia,Distichlis spicata and S.airoides)exhibited correlations with stomatal conductance and concentrations of nutrients.Results indicate that differential physiological response mechanisms to increased moisture and associated nutrient uptake strategies in drought-adapted species may mediate coexistence under increased summer precipitation.展开更多
文摘Since 1947 （Addy） [1, 2], marine biologists have conducted experiments in order to re-establish meadows using various methods of transplant. A 27-month experiment of germinating and growing Posidonia oceanica （L.） Delile seeds was carried out in two areas near Piombino in the Leghorn Province （Italy）. Seeds in direct contact with the sea bottom were taken from other seaside areas. The leaf growth and the percentage of well-developed plants in the study areas were calculated. The results confirm that this method appears to be a good re-establishment technique despite the problems associated with finding a large number of seeds anywhere along Mediterranean coasts.
文摘Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge is important since drought-adapted plants exhibit varied mechanisms of survival that may contribute to species coexistence.Methods We tested the responses of eight drought-adapted plants,a mix of graminoids,shrubs and forbs to three summer precipitation scenarios(1.3,2.6 and 3.9 cm per month)in a common garden experiment in the Great Basin(Owens Valley,California).Changes in mineral nutrient uptake(carbon,nitrogen,phosphorus,potassium,calcium,magnesium,manganese,copper,boron,zinc,iron and sodium)and gas exchange parameters(photosynthetic rate and stomatal conductance)were investigated in the studied species.Important Findings Two graminoids(Sporobolus airoides and Leymus triticoides)and one salt tolerant shrub species(Atriplex confertifolia)responded to increased water availability with increases in photosynthetic rate and/or stomatal conductance.There was a significant correlation between water availability and uptake of nutrients for five out of eight species.Artemisia tridentata,with higher rates of photosynthesis,contained greater amounts of potassium,copper and boron,while Juncus arcticus,with higher rates of photosynthesis,contained greater amounts of magnesium and iron,and less sodium.Juncus arcticus and three salt-adapted species(A.confertifolia,Distichlis spicata and S.airoides)exhibited correlations with stomatal conductance and concentrations of nutrients.Results indicate that differential physiological response mechanisms to increased moisture and associated nutrient uptake strategies in drought-adapted species may mediate coexistence under increased summer precipitation.
