How can we regulate an invasive alien species of high commercial value?Black locust(Robinia pseudoacacia L.)has a unique capacity for seed dispersal and high germination.Field surveys indicate that black locust increa...How can we regulate an invasive alien species of high commercial value?Black locust(Robinia pseudoacacia L.)has a unique capacity for seed dispersal and high germination.Field surveys indicate that black locust increases its growing area with sprouting roots and the elongation of horizontal roots at a soil depth of 10 cm.Therefore,a method to regulate the development of horizontal roots could be eff ective in slowing the invasiveness of black locust.In this study,root barrier panels were tested to inhibit the growth of horizontal roots.Since it is labor intensive to observe the growth of roots in the fi eld,it was investigated in a nursery setting.The decrease in secondary fl ush,an increase in yellowed leafl ets,and the height in the seedlings were measured.Installing root barrier panels to a depth of 30 cm eff ectively inhibit the growth of horizontal roots of young black locust.展开更多
Cadmium (Cd) is a toxic metal with high mobility from soil and known translocation into plants (Song et al., 2015).Because the main source of human exposure to Cd is from food consumption, there has been increased res...Cadmium (Cd) is a toxic metal with high mobility from soil and known translocation into plants (Song et al., 2015).Because the main source of human exposure to Cd is from food consumption, there has been increased research examining Cd uptake in agricultural plants (Li et al., 2014;Rizwan et al., 2016;Song et al., 2015).展开更多
A clear description of the certain mechanisms of cadmium(Cd) uptake and translocation in rice(Oryza sativa L.) may help to reduce Cd accumulation in rice grain. Hydroponic experiments were carried out to determine the...A clear description of the certain mechanisms of cadmium(Cd) uptake and translocation in rice(Oryza sativa L.) may help to reduce Cd accumulation in rice grain. Hydroponic experiments were carried out to determine the effects of cultivation conditions(aerated and stagnant) on the uptake, translocation and subcellular distribution of Cd in relation to the morphology and anatomy of roots in two rice genotypes with different Cd accumulations in grains. Marked differences in morphology and anatomy were observed between these two genotypes under different cultivation conditions. Genotypes with low Cd accumulation in grains tended to develop fewer root tips per root surface area, larger root porosity and more mature apoplastic barriers. The stagnant cultivation condition decreased the number of root tips per root surface area but increased root porosity and accelerated apoplastic barrier formation in root tissues.Correlative Cd uptake studies revealed that rice plants with fewer number of root tips per root surface area reduced root Cd uptake ability, while mature apoplastic barriers increased root Cd retention in cell walls and the symplast. Thus, the fewer number of root tips per root surface area and the earlier formation of mature apoplastic barriers led to lower Cd uptake and translocation. The results indicated that the morphology and anatomy of roots could play important roles in Cd uptake and translocation in rice, and could be influenced by both genotype and cultivation conditions. The present results would be useful in screening and planting rice plants with low Cd accumulation.展开更多
目的探讨iRoot BP Plus治疗恒牙根尖敞开病变的临床效果。方法选取2019年1月至2020年1月韶关市口腔医院牙体牙髓科收治的根尖孔未闭合的成年患者52例,前牙及前磨牙共60颗为研究对象,按照就诊顺序分为试验组与对照组,每组30颗牙。对照组...目的探讨iRoot BP Plus治疗恒牙根尖敞开病变的临床效果。方法选取2019年1月至2020年1月韶关市口腔医院牙体牙髓科收治的根尖孔未闭合的成年患者52例,前牙及前磨牙共60颗为研究对象,按照就诊顺序分为试验组与对照组,每组30颗牙。对照组在清理完根管后,口腔显微镜下采用氢氧化钙类根管糊剂Vitapex行根尖诱导成形术,试验组在口腔显微镜下将iRoot BP Plus充填于根尖孔及根管下段,厚约3~5 mm,硬固后采用热牙胶完成根管中上段的充填。比较两组的患者就诊次数、治疗周期、治疗效果及换牙疼痛发生率。结果试验组的平均就诊次数、治疗周期短于对照组,差异有统计学意义(P<0.05);试验组根尖封闭成功率高于对照组,差异有统计学意义(P<0.05)。两组患者均未发生术后急性反应。结论iRoot BP Plus根尖屏障联合热牙胶根管充填用于治疗恒牙根尖敞开病变相对于氢氧化钙类根管糊剂Vitapex行根尖诱导成形术明显就诊次数少、治疗周期短、成功率高,值得临床推广。展开更多
Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three di...Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture （control） or artificially structured （smart design, SD） soil substrates. Rhodes grass and ivy （Ipomea, Convolvulaceae） were grown in the pots during the hottest season in Oman. Soil moisture content （SMC） was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass （SMC of around 25%-30% compared to 〈10% for control, 3 days after the last irrigation）. Even after 20 days, SMC was around 18% in the SD and 7% in the control. This, similar to the case of a natural prototype, is attributed to the higher upward capillary movement of water in control pots and intensive evaporation. The capillary barrier of sand sheaths causes discontinuity in moisture mi- gration from the micro-pores in the silt blocks to sand pores. The blocks serve as capillarity-locked water buffers, which are depleted at a slow rate by transpiration rather than evaporation from the soil surface. This creates a unique ecosystem with a dramatic difference in vegetation between SD-pots and control pots. Consequently, the Noy-Meir edaphic factor, conceptualizing the ecological impact of 1-D vertical heterogeneity of desert soils, should be generalized to incorporate 3-D soil heterogeneity patterns. This agro-engineering control of the soil substrate and soil moisture distribution and dynamics （SMDaD） can be widely used by desert farmers as a cheap technique, with significant savings of irrigation water.展开更多
基金supported in part by the Research Faculty of Agriculture of Hokkaido University.
文摘How can we regulate an invasive alien species of high commercial value?Black locust(Robinia pseudoacacia L.)has a unique capacity for seed dispersal and high germination.Field surveys indicate that black locust increases its growing area with sprouting roots and the elongation of horizontal roots at a soil depth of 10 cm.Therefore,a method to regulate the development of horizontal roots could be eff ective in slowing the invasiveness of black locust.In this study,root barrier panels were tested to inhibit the growth of horizontal roots.Since it is labor intensive to observe the growth of roots in the fi eld,it was investigated in a nursery setting.The decrease in secondary fl ush,an increase in yellowed leafl ets,and the height in the seedlings were measured.Installing root barrier panels to a depth of 30 cm eff ectively inhibit the growth of horizontal roots of young black locust.
文摘Cadmium (Cd) is a toxic metal with high mobility from soil and known translocation into plants (Song et al., 2015).Because the main source of human exposure to Cd is from food consumption, there has been increased research examining Cd uptake in agricultural plants (Li et al., 2014;Rizwan et al., 2016;Song et al., 2015).
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China (No.EdUHK 28100014)the National Natural Science Foundation of China (No.31670409)+1 种基金the Natural Science Foundation of Guangdong,China (No.2016A030313273)the Faculty of Liberal Arts and Social Sciences (No.04021) of The Education University of Hong Kong
文摘A clear description of the certain mechanisms of cadmium(Cd) uptake and translocation in rice(Oryza sativa L.) may help to reduce Cd accumulation in rice grain. Hydroponic experiments were carried out to determine the effects of cultivation conditions(aerated and stagnant) on the uptake, translocation and subcellular distribution of Cd in relation to the morphology and anatomy of roots in two rice genotypes with different Cd accumulations in grains. Marked differences in morphology and anatomy were observed between these two genotypes under different cultivation conditions. Genotypes with low Cd accumulation in grains tended to develop fewer root tips per root surface area, larger root porosity and more mature apoplastic barriers. The stagnant cultivation condition decreased the number of root tips per root surface area but increased root porosity and accelerated apoplastic barrier formation in root tissues.Correlative Cd uptake studies revealed that rice plants with fewer number of root tips per root surface area reduced root Cd uptake ability, while mature apoplastic barriers increased root Cd retention in cell walls and the symplast. Thus, the fewer number of root tips per root surface area and the earlier formation of mature apoplastic barriers led to lower Cd uptake and translocation. The results indicated that the morphology and anatomy of roots could play important roles in Cd uptake and translocation in rice, and could be influenced by both genotype and cultivation conditions. The present results would be useful in screening and planting rice plants with low Cd accumulation.
文摘目的探讨iRoot BP Plus治疗恒牙根尖敞开病变的临床效果。方法选取2019年1月至2020年1月韶关市口腔医院牙体牙髓科收治的根尖孔未闭合的成年患者52例,前牙及前磨牙共60颗为研究对象,按照就诊顺序分为试验组与对照组,每组30颗牙。对照组在清理完根管后,口腔显微镜下采用氢氧化钙类根管糊剂Vitapex行根尖诱导成形术,试验组在口腔显微镜下将iRoot BP Plus充填于根尖孔及根管下段,厚约3~5 mm,硬固后采用热牙胶完成根管中上段的充填。比较两组的患者就诊次数、治疗周期、治疗效果及换牙疼痛发生率。结果试验组的平均就诊次数、治疗周期短于对照组,差异有统计学意义(P<0.05);试验组根尖封闭成功率高于对照组,差异有统计学意义(P<0.05)。两组患者均未发生术后急性反应。结论iRoot BP Plus根尖屏障联合热牙胶根管充填用于治疗恒牙根尖敞开病变相对于氢氧化钙类根管糊剂Vitapex行根尖诱导成形术明显就诊次数少、治疗周期短、成功率高,值得临床推广。
基金support from the Grant IG/AGR/SWAE/10/02 of the Sultan Qaboos University
文摘Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture （control） or artificially structured （smart design, SD） soil substrates. Rhodes grass and ivy （Ipomea, Convolvulaceae） were grown in the pots during the hottest season in Oman. Soil moisture content （SMC） was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass （SMC of around 25%-30% compared to 〈10% for control, 3 days after the last irrigation）. Even after 20 days, SMC was around 18% in the SD and 7% in the control. This, similar to the case of a natural prototype, is attributed to the higher upward capillary movement of water in control pots and intensive evaporation. The capillary barrier of sand sheaths causes discontinuity in moisture mi- gration from the micro-pores in the silt blocks to sand pores. The blocks serve as capillarity-locked water buffers, which are depleted at a slow rate by transpiration rather than evaporation from the soil surface. This creates a unique ecosystem with a dramatic difference in vegetation between SD-pots and control pots. Consequently, the Noy-Meir edaphic factor, conceptualizing the ecological impact of 1-D vertical heterogeneity of desert soils, should be generalized to incorporate 3-D soil heterogeneity patterns. This agro-engineering control of the soil substrate and soil moisture distribution and dynamics （SMDaD） can be widely used by desert farmers as a cheap technique, with significant savings of irrigation water.
