Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that （1） defoliation reduce net primary productivity, and root...Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that （1） defoliation reduce net primary productivity, and root length density and weight in the native species, and （2） root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species （i.e., Aristida spegazzinfi, A. subulata and Sporobolus cryptandrus）. Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season （2008-2009）, cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid- and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den- sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.展开更多
The response of plant leaf and root phenology and biomass in the Arctic to global change remains unclear due to the lack of synchronous measurements of above-and belowground parts.Our objective was to determine the ph...The response of plant leaf and root phenology and biomass in the Arctic to global change remains unclear due to the lack of synchronous measurements of above-and belowground parts.Our objective was to determine the phenological dynamics of the above-and belowground parts of Eriophorum vaginatum in the Arctic and its response to warming.We established a common garden located at Toolik Lake Field Station;tussocks of E.vaginatum from three locations,Coldfoot,Toolik Lake and Sagwon,were transplanted into the common garden.Control and warming treatments for E.vaginatum were set up at the Toolik Lake during the growing seasons of 2016 and 2017.Digital cameras,a handheld sensor and minirhizotrons were used to simultaneously observe leaf greenness,normalized difference vegetation index and root length dynamics,respectively.Leaf and root growth rates of E.vaginatum were asynchronous such that the timing of maximal leaf growth(mid-july)was about 28 days earlier than that of root growth.Warming of air temperature by 1°C delayed the timing of leaf senescence and thus prolonged the growing season,but the temperature increase had no significant effect on root phenology.The seasonal dynamics of leaf biomass were affected by air temperature,whereas root biomass was correlated with soil thaw depth.Therefore,we suggest that leaf and root components should be considered comprehensively when using carbon and nutrient cycle models,as above-and belowground productivity and functional traits may have a different response to climate warming.展开更多
The physiological responses of Paspalum vaginatum Sw. to Cd stress and its Cd accumulation characteristics were studied by investigating the effects of different concentrations of Cd on the growth, root vigor, leaf me...The physiological responses of Paspalum vaginatum Sw. to Cd stress and its Cd accumulation characteristics were studied by investigating the effects of different concentrations of Cd on the growth, root vigor, leaf membrane permeability, membrane lipid peroxidation, protective enzyme activity and Cd accumulation of P. vaginatum. When the Cd concentration was over 50.00 mg/kg, with the increased Cd concentration, the CAT activity declined significantly, the synergistic effect between SOD and CAT was weakened, the MDA content increased greatly, and the root vigor decreased, leading to inhibited growth of P. vaginatum. When the Cd concentration was in the range of 0-50 mg/kg, the root vigor of P. vaginatum did not decline obviously, the activity of protective enzymes （SOD and CAT） was enhanced, and the MDA accumulation and cell membrane permeability did not increase significantly, thus the damage of Cd to P. vaginatum was lighter. Roots of P. vaginatum showed strong enrichment capacity for Cd. When the Cd concentration was up to 200.00 mg/kg, the Cd contents in shoot and root of P. vaginatum reached 39.15 and 1 097.38 mg/kg, respectively. It suggests that in the concentration range of 0-50.00 mg/kg, P. vaginatum can make effective responses to Cd stress and grow normally, and it can be planted as a candidate material to remediate Cd-contaminated soil.展开更多
本研究于2006-2008年在江苏金沙湾乡村俱乐部进行,明确该球场有草坪杂草29科95种,其中禾本科19种,莎草科3种,阔叶草27科73种。其中春季萌发的有50种,秋季萌发的36种,春、秋季都萌发的9种。建场初,杂草种类仍保留原生态系的痕迹,经过草...本研究于2006-2008年在江苏金沙湾乡村俱乐部进行,明确该球场有草坪杂草29科95种,其中禾本科19种,莎草科3种,阔叶草27科73种。其中春季萌发的有50种,秋季萌发的36种,春、秋季都萌发的9种。建场初,杂草种类仍保留原生态系的痕迹,经过草坪管理特别是剪草及应用除草剂,杂草种类转为以草坪伴生杂草为优势种。田间杂草化学防除试验表明,砜嘧磺隆（Rimsulfuron,n-{[（4,6-dimethoxy-2-pyrimidinyl）amino]carbonyl}-3-（ethylsulfonyl）-2-pyridinesulfonamide）0.045-0.030 kg ai/hm^2与嗪磺隆[Chlorsulfuron,1-2-chlorophenylsulfonyl-3-（4-methoxy-1,3,5-triazin-2-yl）urea]0.020 0-0.022 8 kg ai/hm^2混配秋季在海滨雀稗应用,药后61和115 d,对禾草和阔叶草防效为65.4%-94.8%。氯吡嘧磺隆（Halosulfuron-methyl,methyl 5-{[（4,6-dimethoxy-2-pyrimidi-nyl）amino]carbonylaminosulfonyl}-3-chloro-1-methyl-1H-pyrazole-4-carboxylate）0.037 5-0.052 5 kg ai/hm^2与砜嘧磺隆0.045-0.030 kg ai/hm^2混配秋季在海滨雀稗应用,药后49和103 d,对多年生黑麦草、一年生早熟禾防效为69.4%-71.2%。砜嘧磺隆0.06 kg ai/hm^2、氯吡嘧磺隆0.067 5 kg ai/hm^2及嗪磺隆0.022 8 kg ai/hm^2对建植1年的海滨雀稗（品种：Salam）生长无影响或甚微,砜嘧磺隆0.18 kg ai/hm^2药后2-4周对海滨雀稗有可见影响,直到药后36周才恢复。展开更多
基金National Council for Scientific and Technological Research of Argentina (CONICET PIP Ner. 00211)
文摘Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that （1） defoliation reduce net primary productivity, and root length density and weight in the native species, and （2） root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species （i.e., Aristida spegazzinfi, A. subulata and Sporobolus cryptandrus）. Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season （2008-2009）, cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid- and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den- sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.
基金the Office of Polar Programs(National Science Foundation)(1417763 to J.T.,1418010 to N.F.and 1417645 to M.L.M.).
文摘The response of plant leaf and root phenology and biomass in the Arctic to global change remains unclear due to the lack of synchronous measurements of above-and belowground parts.Our objective was to determine the phenological dynamics of the above-and belowground parts of Eriophorum vaginatum in the Arctic and its response to warming.We established a common garden located at Toolik Lake Field Station;tussocks of E.vaginatum from three locations,Coldfoot,Toolik Lake and Sagwon,were transplanted into the common garden.Control and warming treatments for E.vaginatum were set up at the Toolik Lake during the growing seasons of 2016 and 2017.Digital cameras,a handheld sensor and minirhizotrons were used to simultaneously observe leaf greenness,normalized difference vegetation index and root length dynamics,respectively.Leaf and root growth rates of E.vaginatum were asynchronous such that the timing of maximal leaf growth(mid-july)was about 28 days earlier than that of root growth.Warming of air temperature by 1°C delayed the timing of leaf senescence and thus prolonged the growing season,but the temperature increase had no significant effect on root phenology.The seasonal dynamics of leaf biomass were affected by air temperature,whereas root biomass was correlated with soil thaw depth.Therefore,we suggest that leaf and root components should be considered comprehensively when using carbon and nutrient cycle models,as above-and belowground productivity and functional traits may have a different response to climate warming.
文摘The physiological responses of Paspalum vaginatum Sw. to Cd stress and its Cd accumulation characteristics were studied by investigating the effects of different concentrations of Cd on the growth, root vigor, leaf membrane permeability, membrane lipid peroxidation, protective enzyme activity and Cd accumulation of P. vaginatum. When the Cd concentration was over 50.00 mg/kg, with the increased Cd concentration, the CAT activity declined significantly, the synergistic effect between SOD and CAT was weakened, the MDA content increased greatly, and the root vigor decreased, leading to inhibited growth of P. vaginatum. When the Cd concentration was in the range of 0-50 mg/kg, the root vigor of P. vaginatum did not decline obviously, the activity of protective enzymes （SOD and CAT） was enhanced, and the MDA accumulation and cell membrane permeability did not increase significantly, thus the damage of Cd to P. vaginatum was lighter. Roots of P. vaginatum showed strong enrichment capacity for Cd. When the Cd concentration was up to 200.00 mg/kg, the Cd contents in shoot and root of P. vaginatum reached 39.15 and 1 097.38 mg/kg, respectively. It suggests that in the concentration range of 0-50.00 mg/kg, P. vaginatum can make effective responses to Cd stress and grow normally, and it can be planted as a candidate material to remediate Cd-contaminated soil.
文摘本研究于2006-2008年在江苏金沙湾乡村俱乐部进行,明确该球场有草坪杂草29科95种,其中禾本科19种,莎草科3种,阔叶草27科73种。其中春季萌发的有50种,秋季萌发的36种,春、秋季都萌发的9种。建场初,杂草种类仍保留原生态系的痕迹,经过草坪管理特别是剪草及应用除草剂,杂草种类转为以草坪伴生杂草为优势种。田间杂草化学防除试验表明,砜嘧磺隆（Rimsulfuron,n-{[（4,6-dimethoxy-2-pyrimidinyl）amino]carbonyl}-3-（ethylsulfonyl）-2-pyridinesulfonamide）0.045-0.030 kg ai/hm^2与嗪磺隆[Chlorsulfuron,1-2-chlorophenylsulfonyl-3-（4-methoxy-1,3,5-triazin-2-yl）urea]0.020 0-0.022 8 kg ai/hm^2混配秋季在海滨雀稗应用,药后61和115 d,对禾草和阔叶草防效为65.4%-94.8%。氯吡嘧磺隆（Halosulfuron-methyl,methyl 5-{[（4,6-dimethoxy-2-pyrimidi-nyl）amino]carbonylaminosulfonyl}-3-chloro-1-methyl-1H-pyrazole-4-carboxylate）0.037 5-0.052 5 kg ai/hm^2与砜嘧磺隆0.045-0.030 kg ai/hm^2混配秋季在海滨雀稗应用,药后49和103 d,对多年生黑麦草、一年生早熟禾防效为69.4%-71.2%。砜嘧磺隆0.06 kg ai/hm^2、氯吡嘧磺隆0.067 5 kg ai/hm^2及嗪磺隆0.022 8 kg ai/hm^2对建植1年的海滨雀稗（品种：Salam）生长无影响或甚微,砜嘧磺隆0.18 kg ai/hm^2药后2-4周对海滨雀稗有可见影响,直到药后36周才恢复。
