Globally,forests play a critical role in regulating the hydrological cycle,supplying water to ecosystems and people.However,both forests and this cycle are undergoing rapid changes[1],[2].Future states of forests and ...Globally,forests play a critical role in regulating the hydrological cycle,supplying water to ecosystems and people.However,both forests and this cycle are undergoing rapid changes[1],[2].Future states of forests and the associated hydrological cycle remain highly uncertain,influenced by altered disturbance regimes such as increasingly frequent and severe wildfires,droughts,and hurricanes,as well as gradual changes such as sea level rise,warming temperatures,and shifts in the amount,seasonal pattern,and form of precipitation[3].Human activities in forested areas compound these changes,potentially intensifying extreme events,such as floods and droughts[1],[2].Consequently,there is an urgent need to manage global forests for ensuring water provision while minimizing associated risks[4].Yet,it remains unclear how the insights from a century of forest-water research can be applied in these emerging contexts.展开更多
Aims osmolytes,used for maintaining osmotic balance and as‘osmoprotectants’,are synthesized in plants as a general,con-served response to abiotic stress,although their contribution to stress-tolerance mechanisms rem...Aims osmolytes,used for maintaining osmotic balance and as‘osmoprotectants’,are synthesized in plants as a general,con-served response to abiotic stress,although their contribution to stress-tolerance mechanisms remains unclear.Proline,the most common osmolyte,accumulates in many plant species in parallel with increased external salinity and is considered a reliable bio-chemical marker of salt stress.We have measured proline levels in two halophytic,closely related Juncus species under laboratory and field conditions to assess the possible relevance of proline biosynthesis for salt tolerance and therefore for the ecology of these two taxa.Methods Proline was quantified in plants treated with increasing NaCl con-centrations and in plants sampled in two salt marshes located in the provinces of Valencia and alicante,respectively,in southeast spain.Electrical conductivity,pH,Na+and Cl−concentrations were measured in soil samples collected in parallel with the plant material.Important Findings Treatment with NaCl inhibited growth of J.acutus plants in a concentration-dependent manner,but only under high salt conditions for J.maritimus.salt treatments led to proline accumulation in both species,especially in the more salt-tolerant J.maritimus.The results,obtained under laboratory conditions,were confirmed in plants sam-pled in the field.in all the samplings,proline contents were signifi-cantly lower in J.acutus than in the more tolerant J.maritimus growing in the same area.No direct correlation between soil salinity and proline levels could be established,but seasonal variations were detected,with increased proline contents under accentuated water deficit conditions.our results suggest that proline biosynthesis is not only an induced,general response to salt stress but also an important contributing factor in the physiological mechanisms of salt tolerance in Juncus,and that it therefore correlates with the ecology of both species.展开更多
文摘Globally,forests play a critical role in regulating the hydrological cycle,supplying water to ecosystems and people.However,both forests and this cycle are undergoing rapid changes[1],[2].Future states of forests and the associated hydrological cycle remain highly uncertain,influenced by altered disturbance regimes such as increasingly frequent and severe wildfires,droughts,and hurricanes,as well as gradual changes such as sea level rise,warming temperatures,and shifts in the amount,seasonal pattern,and form of precipitation[3].Human activities in forested areas compound these changes,potentially intensifying extreme events,such as floods and droughts[1],[2].Consequently,there is an urgent need to manage global forests for ensuring water provision while minimizing associated risks[4].Yet,it remains unclear how the insights from a century of forest-water research can be applied in these emerging contexts.
基金Spanish Ministry of Science and Innovation and European Regional Development Fund to O.V.(CGL2008-00438/BOS)Polytechnic University of Valencia to M.B.(PAID-06-09).
文摘Aims osmolytes,used for maintaining osmotic balance and as‘osmoprotectants’,are synthesized in plants as a general,con-served response to abiotic stress,although their contribution to stress-tolerance mechanisms remains unclear.Proline,the most common osmolyte,accumulates in many plant species in parallel with increased external salinity and is considered a reliable bio-chemical marker of salt stress.We have measured proline levels in two halophytic,closely related Juncus species under laboratory and field conditions to assess the possible relevance of proline biosynthesis for salt tolerance and therefore for the ecology of these two taxa.Methods Proline was quantified in plants treated with increasing NaCl con-centrations and in plants sampled in two salt marshes located in the provinces of Valencia and alicante,respectively,in southeast spain.Electrical conductivity,pH,Na+and Cl−concentrations were measured in soil samples collected in parallel with the plant material.Important Findings Treatment with NaCl inhibited growth of J.acutus plants in a concentration-dependent manner,but only under high salt conditions for J.maritimus.salt treatments led to proline accumulation in both species,especially in the more salt-tolerant J.maritimus.The results,obtained under laboratory conditions,were confirmed in plants sam-pled in the field.in all the samplings,proline contents were signifi-cantly lower in J.acutus than in the more tolerant J.maritimus growing in the same area.No direct correlation between soil salinity and proline levels could be established,but seasonal variations were detected,with increased proline contents under accentuated water deficit conditions.our results suggest that proline biosynthesis is not only an induced,general response to salt stress but also an important contributing factor in the physiological mechanisms of salt tolerance in Juncus,and that it therefore correlates with the ecology of both species.
