[Objective] This study aimed to investigate the effects of traffic stress on the physiological characteristics of Agrostis stolonifera under high temperature and humidity in summer. [Method] Total 3 creeping bentgrass...[Objective] This study aimed to investigate the effects of traffic stress on the physiological characteristics of Agrostis stolonifera under high temperature and humidity in summer. [Method] Total 3 creeping bentgrass varieties （lines） were se- lected as materials, and their physiological characteristics were determined and ana- lyzed, including leaf relative water content, relative plasma membrane permeability, peroxidase activity, superoxide dismutase （SOD） activity, catalase activity, proline content and malondialdehyde （MDA） content. [Result] Under the traffic stress, the leaf relative water content, relative plasma membrane permeability, MDA content, proline content and protection enzymes activities showed significant differences among different traffic intensities and tested varieties （P〈0.05）. The variations of various physiological indexes of Yuexuan 1 were smallest, and it showed relatively strong traffic tolerance. [Conclusion] Considering the traffic tolerance, the 3 tested creeping bentgrass varieties ranked as Yuexuan 1〉New Strain No.2〉Penncross.展开更多
Soil water potential indicates the water status of the soil and the need for irrigation. The effect of hydrogel amendment to the upper sand soil layer on water infiltration into the lower un-amended sand layer, irriga...Soil water potential indicates the water status of the soil and the need for irrigation. The effect of hydrogel amendment to the upper sand soil layer on water infiltration into the lower un-amended sand layer, irrigation frequency, water use efficiency and biomass production of Agrostis stolonifera was investigated. The upper 25 cm sand layer in three identical buckets was amended at 0.4%, 0.2% and a control (no hydrogel) while the lower 25 cm sand layer separated from the upper layer by a wire mesh in the same buckets was un-amended. Agrostis stolonifera seeds were sown in each bucket and adequately irrigated using a hand sprayer. Potential meter electrodes were inserted at three random positions in each of the buckets and subsequent irrigations were done when a pressure of 600 bars was recorded in any of the three treatments. Data were collected on irrigation frequency, water content in the lower layer, water use efficiency and biomass production of Agrostis stolonifera. The mean water potential in the lower 25 cm layer un-amended sand was significantly more negative in the 0.4% hydrogel than in the control. More water content (10%) was recorded in the lower layer under the control bucket than in either the 0.2% and 0.4% hydrogel amended buckets. The frequency of irrigation was three-fold in the control compared to the 0.4% hydrogel amended sand. The hydrogel amended sand significantly increased the shoot and root biomass of Agrostis stolonifera by 2.2 and 4 times respectively compared to the control. The 0.4% hydrogel amendment in sand increased the water use efficiency of grass eight fold with respect to the control. The hydrogel stimulated development of a dense root network and root aggregation that increased contact of the roots with moisture thus improving water use efficiency of hydrogel amended soil. The results suggest that hydrogels can improve sandy soil properties for plant growth by absorbing and keeping water longer in the soil matrix thus reducing watering frequency.展开更多
Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precult...Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4-7 days and then co cultivated with Agrobacterium tumefaciens , LBA4404, which contains plasmid vector pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4 D, 12-15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2-3 months of selection, the actively growing calli of 'Regent' and 'Tiger' were transferred to MS medium with 12-15 mg/L PPT and 250 mg/L cefotaxime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.展开更多
Several abiotic and biotic factors were investigated as possible predictors of local species richness in two sub-alpine grasslands of Jenna and Belles Mountains in Northern Greece.For species richness modelling a hier...Several abiotic and biotic factors were investigated as possible predictors of local species richness in two sub-alpine grasslands of Jenna and Belles Mountains in Northern Greece.For species richness modelling a hierarchical modelling framework based on generalized additive models was adopted.The two sub-alpine grasslands differed in aspect,altitude and soil parent material(volcanic origin,mostly trachyte,and andesite(TA) for Jenna and metamorphic rocks,mostly gneiss(G) for Belles).12 fenced squared plots,16 m2 each,were used per grassland,where soil properties,herbage production,species presence and cover of grasses,legumes and forbs were estimated.Mean herbage production was significantly affected by slope and altitude,soil K content and floristic composition as expressed by an ordination axis.Soil p H,floristic composition and average herbage production were significant predictors of forbs and total species richness.For the former,soil N content and for the latter the occurrence of Agrostis capillaris,were also included as significant terms in the predictive model.Thepredictors for grasses species richness were N content,having a positive effect,and average herbage production.In all cases higher species richness was predicted for intermediate values of average herbage production.Differential responses were found between forbs and grasses.The predictors of their species richness were different while for the case of the common predictor(N) the responses of the two groups were also different(grasses species numbers increase and forbs species numbers decreased with increasing N).Maximum species richness of grasses was observed at relatively low production levels while forbs species richness maximized at relatively high production levels.展开更多
文摘[Objective] This study aimed to investigate the effects of traffic stress on the physiological characteristics of Agrostis stolonifera under high temperature and humidity in summer. [Method] Total 3 creeping bentgrass varieties （lines） were se- lected as materials, and their physiological characteristics were determined and ana- lyzed, including leaf relative water content, relative plasma membrane permeability, peroxidase activity, superoxide dismutase （SOD） activity, catalase activity, proline content and malondialdehyde （MDA） content. [Result] Under the traffic stress, the leaf relative water content, relative plasma membrane permeability, MDA content, proline content and protection enzymes activities showed significant differences among different traffic intensities and tested varieties （P〈0.05）. The variations of various physiological indexes of Yuexuan 1 were smallest, and it showed relatively strong traffic tolerance. [Conclusion] Considering the traffic tolerance, the 3 tested creeping bentgrass varieties ranked as Yuexuan 1〉New Strain No.2〉Penncross.
文摘Soil water potential indicates the water status of the soil and the need for irrigation. The effect of hydrogel amendment to the upper sand soil layer on water infiltration into the lower un-amended sand layer, irrigation frequency, water use efficiency and biomass production of Agrostis stolonifera was investigated. The upper 25 cm sand layer in three identical buckets was amended at 0.4%, 0.2% and a control (no hydrogel) while the lower 25 cm sand layer separated from the upper layer by a wire mesh in the same buckets was un-amended. Agrostis stolonifera seeds were sown in each bucket and adequately irrigated using a hand sprayer. Potential meter electrodes were inserted at three random positions in each of the buckets and subsequent irrigations were done when a pressure of 600 bars was recorded in any of the three treatments. Data were collected on irrigation frequency, water content in the lower layer, water use efficiency and biomass production of Agrostis stolonifera. The mean water potential in the lower 25 cm layer un-amended sand was significantly more negative in the 0.4% hydrogel than in the control. More water content (10%) was recorded in the lower layer under the control bucket than in either the 0.2% and 0.4% hydrogel amended buckets. The frequency of irrigation was three-fold in the control compared to the 0.4% hydrogel amended sand. The hydrogel amended sand significantly increased the shoot and root biomass of Agrostis stolonifera by 2.2 and 4 times respectively compared to the control. The 0.4% hydrogel amendment in sand increased the water use efficiency of grass eight fold with respect to the control. The hydrogel stimulated development of a dense root network and root aggregation that increased contact of the roots with moisture thus improving water use efficiency of hydrogel amended soil. The results suggest that hydrogels can improve sandy soil properties for plant growth by absorbing and keeping water longer in the soil matrix thus reducing watering frequency.
文摘Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4-7 days and then co cultivated with Agrobacterium tumefaciens , LBA4404, which contains plasmid vector pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4 D, 12-15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2-3 months of selection, the actively growing calli of 'Regent' and 'Tiger' were transferred to MS medium with 12-15 mg/L PPT and 250 mg/L cefotaxime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.
基金The Greek Ministry of Agriculture is gratefully acknowledged for their support
文摘Several abiotic and biotic factors were investigated as possible predictors of local species richness in two sub-alpine grasslands of Jenna and Belles Mountains in Northern Greece.For species richness modelling a hierarchical modelling framework based on generalized additive models was adopted.The two sub-alpine grasslands differed in aspect,altitude and soil parent material(volcanic origin,mostly trachyte,and andesite(TA) for Jenna and metamorphic rocks,mostly gneiss(G) for Belles).12 fenced squared plots,16 m2 each,were used per grassland,where soil properties,herbage production,species presence and cover of grasses,legumes and forbs were estimated.Mean herbage production was significantly affected by slope and altitude,soil K content and floristic composition as expressed by an ordination axis.Soil p H,floristic composition and average herbage production were significant predictors of forbs and total species richness.For the former,soil N content and for the latter the occurrence of Agrostis capillaris,were also included as significant terms in the predictive model.Thepredictors for grasses species richness were N content,having a positive effect,and average herbage production.In all cases higher species richness was predicted for intermediate values of average herbage production.Differential responses were found between forbs and grasses.The predictors of their species richness were different while for the case of the common predictor(N) the responses of the two groups were also different(grasses species numbers increase and forbs species numbers decreased with increasing N).Maximum species richness of grasses was observed at relatively low production levels while forbs species richness maximized at relatively high production levels.
