With the expansion of eucalyptus crops to areas with severe water limitations,physiological studies involving eucalyptus clones to identify those that are tolerant to water stress become important.The objective of thi...With the expansion of eucalyptus crops to areas with severe water limitations,physiological studies involving eucalyptus clones to identify those that are tolerant to water stress become important.The objective of this study was to assess morphological and physiological responses by eucalyptus clones subjected to drought stress and rehydration.The experiment consisted of three eucalyptus clones:VC865,I224 and I144 and two water regimes:control and water stress followed by rehydration,with six replicates.Leaf water potential,gas exchange,maximum quantum efficiency of photo systemⅡand plant height and stem diameter were evaluated under drought stress and rehydration.After6 d of rehydration,the number of leaves,leaf area and dry mass of root,leaf,stem and their total were evaluated.All clones showed intense reduction of gas exchange during the drought stress period,and only VC865 and 1144 showed rapid recovery with 3 d of rehydration.Clone 1224 showed greater reduction in height,stem diameter,number of leaves,water potential at midday(Ψ_(w)_(Midday)),and maximum quantum efficiency of photosystemⅡ(F_(v)/F_(m)).Clones VC865and T144 showed lower reductions inΨ_(wMidday)and F_(v)/F_(m) under stress.VC865 had lower reductions in leaf number,leaf area and higher leaf dry mass,while clone I144 had higher height and lower reduction in root dry mass under.Both these clones showed higher water use efficiency with 3d of rehydration.These different phenotypic plasticities gave the clones VC865 and 1144 efficient mechanisms of acclimatization to stress and more drought tolerance,enhancing their greater capacity for recovery after stress,which allowed lower dry mass reduction.Clone 1224,however,was more susceptible to drought stress,undergoing greater physiological damage with only partial recovery during rehydration.展开更多
以黄土高原南部两个长期定位试验（分别开始于1990和2003年）为研究对象,探讨了不同肥料处理对玉米根茬生物产量和养分累积的影响.于2011年10月玉米收获后采集0-20 cm土层不同施肥处理玉米根茬.结果表明：与不施肥及偏施N、NK、PK化肥相...以黄土高原南部两个长期定位试验（分别开始于1990和2003年）为研究对象,探讨了不同肥料处理对玉米根茬生物产量和养分累积的影响.于2011年10月玉米收获后采集0-20 cm土层不同施肥处理玉米根茬.结果表明：与不施肥及偏施N、NK、PK化肥相比,氮磷配施（NP）、氮磷钾平衡施肥（NPK）、有机无机配施（M1NPK、M2NPK）及化肥配合秸秆（SNPK）处理均显著提高了玉米根茬干质量.根茬固碳量及氮、磷、钾养分累积量在NP、NPK、M1NPK、M2NPK、SNPK处理显著高于不施肥和偏施N、NK、PK化肥处理,其中以有机无机配施处理效果最好.与不施氮肥（N0）相比,施氮120 kg N·hm^-2（N120）和240 kg N·hm^-2（N240）处理根茬干质量分别提高38%和45%,高量氮肥对根茬增量效果不显著.施用氮肥也显著提高了根茬碳、氮、磷、钾累积量.根茬可溶性有机碳、可溶性总氮含量在NP、NPK、M1NPK、M2NPK、SNPK及N120和N240处理中较高.氮磷钾平衡施肥、有机无机配施以及秸秆还田处理降低了根茬的纤维素、木质素含量.根茬C/N、木质素/N在CK、PK、N0处理间显著高于其他施肥处理.因此,氮磷配施、氮磷钾平衡施肥、有机无机配施及秸秆还田处理能够促进玉米根生长,提高营养成分含量,有利于土壤培肥和固碳.展开更多
基金supported by the FAPEAL-Foundation for Research Support of the State of Alagoas,Brazil。
文摘With the expansion of eucalyptus crops to areas with severe water limitations,physiological studies involving eucalyptus clones to identify those that are tolerant to water stress become important.The objective of this study was to assess morphological and physiological responses by eucalyptus clones subjected to drought stress and rehydration.The experiment consisted of three eucalyptus clones:VC865,I224 and I144 and two water regimes:control and water stress followed by rehydration,with six replicates.Leaf water potential,gas exchange,maximum quantum efficiency of photo systemⅡand plant height and stem diameter were evaluated under drought stress and rehydration.After6 d of rehydration,the number of leaves,leaf area and dry mass of root,leaf,stem and their total were evaluated.All clones showed intense reduction of gas exchange during the drought stress period,and only VC865 and 1144 showed rapid recovery with 3 d of rehydration.Clone 1224 showed greater reduction in height,stem diameter,number of leaves,water potential at midday(Ψ_(w)_(Midday)),and maximum quantum efficiency of photosystemⅡ(F_(v)/F_(m)).Clones VC865and T144 showed lower reductions inΨ_(wMidday)and F_(v)/F_(m) under stress.VC865 had lower reductions in leaf number,leaf area and higher leaf dry mass,while clone I144 had higher height and lower reduction in root dry mass under.Both these clones showed higher water use efficiency with 3d of rehydration.These different phenotypic plasticities gave the clones VC865 and 1144 efficient mechanisms of acclimatization to stress and more drought tolerance,enhancing their greater capacity for recovery after stress,which allowed lower dry mass reduction.Clone 1224,however,was more susceptible to drought stress,undergoing greater physiological damage with only partial recovery during rehydration.
文摘以黄土高原南部两个长期定位试验（分别开始于1990和2003年）为研究对象,探讨了不同肥料处理对玉米根茬生物产量和养分累积的影响.于2011年10月玉米收获后采集0-20 cm土层不同施肥处理玉米根茬.结果表明：与不施肥及偏施N、NK、PK化肥相比,氮磷配施（NP）、氮磷钾平衡施肥（NPK）、有机无机配施（M1NPK、M2NPK）及化肥配合秸秆（SNPK）处理均显著提高了玉米根茬干质量.根茬固碳量及氮、磷、钾养分累积量在NP、NPK、M1NPK、M2NPK、SNPK处理显著高于不施肥和偏施N、NK、PK化肥处理,其中以有机无机配施处理效果最好.与不施氮肥（N0）相比,施氮120 kg N·hm^-2（N120）和240 kg N·hm^-2（N240）处理根茬干质量分别提高38%和45%,高量氮肥对根茬增量效果不显著.施用氮肥也显著提高了根茬碳、氮、磷、钾累积量.根茬可溶性有机碳、可溶性总氮含量在NP、NPK、M1NPK、M2NPK、SNPK及N120和N240处理中较高.氮磷钾平衡施肥、有机无机配施以及秸秆还田处理降低了根茬的纤维素、木质素含量.根茬C/N、木质素/N在CK、PK、N0处理间显著高于其他施肥处理.因此,氮磷配施、氮磷钾平衡施肥、有机无机配施及秸秆还田处理能够促进玉米根生长,提高营养成分含量,有利于土壤培肥和固碳.
