Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nu...Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nutrient solution is the key to obtain high quality and high yield of hydroponic vegetables over summer. With Lactuca sativa vat. crispa ＇Luosheng No.3＇ as the test material, the effect of chiller cooling technology on the temperature of nutrient solution, as well as on the yield and quality of Luosheng No.3, in over-summer hydroponic cultivation was studied. The results showed that the chiller cooling technology controlled the nutrient solution temperature in a reasonable range （（20 ± 1）℃） and promoted the growth and dry matter accumulation of Luosheng No.3, instead of affecting the quality. In short, the chiller cooling technology is applicable to the temperature regulation of nutrient solu- tion in hydroponics over summer.展开更多
Using conductivity-Temperature-depth data of a recent cruise during July 22-28, 2008 and historical data, it is found that temperature inversions occur from time to time in the Huanghai Sea（Yellow Sea） cold water ma...Using conductivity-Temperature-depth data of a recent cruise during July 22-28, 2008 and historical data, it is found that temperature inversions occur from time to time in the Huanghai Sea（Yellow Sea） cold water mass （HSCWM） in summer. The temperature inversions are produced by the movement of the fresh and cold HSCWM masses above the warm and saline Huanghai Sea Warm Current water at the central bottom of the Huanghai Sea Trough. The non-homogeneous profiles of the temperature and the salinity suggest that vertical mixing in the HSCWM, which is of great importance to the circulation in the Huanghai Sea in summer, is weak. Trajectories of satellite-tracked surface drifters suggest that waters in the northern reach of the Huanghai Sea move southward along the 40-50 m isobaths and descend into the southern Huanghai Sea to form the western core of the HSCWM.展开更多
短命植物是荒漠生态系统重要的植物类群,其具有多样化的生境,且很多种类还具有异时萌发特性。植物生物量积累和分配能体现其对环境的响应与适应性特征,因此,研究不同环境条件下短命植物生物量分配格局有助于进一步了解短命植物的生存策...短命植物是荒漠生态系统重要的植物类群,其具有多样化的生境,且很多种类还具有异时萌发特性。植物生物量积累和分配能体现其对环境的响应与适应性特征,因此,研究不同环境条件下短命植物生物量分配格局有助于进一步了解短命植物的生存策略。以裸沙春萌(Bare Sand-Spring Germination,BS)、藻结皮春萌(Algal-Spring Germination,AS)、地衣结皮春萌(Lichen-Spring Germination,LS)3种自然结皮生境中萌发的尖喙牻牛儿苗春萌株及裸沙区夏季萌发(Summer Germination in Bare Sand,SG)的尖喙牻牛儿苗夏萌株为研究对象,采用全株挖掘法获取地上和地下生物量,系统对比分析了4个类型间植株生物量分配及异速生长关系的差异性,以探究其资源分配策略的变异性和保守型。结果表明:(1)尖喙牻牛儿苗单株地上、地下及总生物量总体表现为BS>AS>LS=SG的格局,其根冠比则呈SG=LS=AS>BS的特征。(2)BS和SG类型植株地上与地下生物量间为等速生长关系,而AS和LS生境为异速生长关系,但4个类型具有共同的异速生长指数(0.8843)。(3)AS和LS生境尖喙牻牛儿苗根冠比随个体增大均呈异速减小趋势,而BS和SG类型植株根冠比则保持相对恒定。可见,尖喙牻牛儿苗生物量分配会受到外界环境及个体发育的影响,并呈现明显的可塑性,在一定程度上反映了其资源分配的保守性与可塑性的权衡。展开更多
Although Pleistocene red paleosols are widely distributed in South China, paleoenviron-mental interpretation has proved difficult because of intense weathering. Here we combine data from molecular fossil and magnetic ...Although Pleistocene red paleosols are widely distributed in South China, paleoenviron-mental interpretation has proved difficult because of intense weathering. Here we combine data from molecular fossil and magnetic properties to reconstruct a record of changes in pedogenic intensity for red paleosols in Southeast China. Depth distribution pattern of magnetic properties indicates that lower （higher） χ but higher （lower） values of HIRM （hard isothermal remanent magnetization） and SIRM （saturation isothermal remanent magnetization）/χ has tight relationship with the intensity of pedogenesis,especially the occurrence of well-developed net-like veins, which is absolutely responsible for the presence of anti-ferromagnetic minerals at the cost of fine-grained SP （superparamagnetic）/SD （single domain） ferrimagnetic minerals. The carbon distribution pattern of n-alkanes, n-alkanols, and n-alkanoic acids reflects the predominant contributions of microorganisms to the organic matter during pedogenesis, which provide direct evidence for strong microbial activities in response to theextremely hot-humid condition while white coarse net-like veins occurrence. Our results demonstrate that the presence of the enhanced East Asia summer monsoon has played a key role in the oxide-dominated weathering regime, and pedogenesis, and microbial activities. Changes in molecular ratios and magnetic properties are used to show that red paleosols have undergone three stages of soil formation in striking response to the evolution of the East Asia summer monsoon： （1） the most effective since the Middle Pleistocene; （2） moderately effective since 270 ka or so; （3） least effective since the last glacial. Our research provides important evidence to understand how red paleosols espond to global change since the Middle Pleistocene.展开更多
基金Supported by Science and Technology Innovative Leading Fund of Ningxia Academy of Agriculture and Forestry Sciences(NKYZ-16-1101)~~
文摘Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nutrient solution is the key to obtain high quality and high yield of hydroponic vegetables over summer. With Lactuca sativa vat. crispa ＇Luosheng No.3＇ as the test material, the effect of chiller cooling technology on the temperature of nutrient solution, as well as on the yield and quality of Luosheng No.3, in over-summer hydroponic cultivation was studied. The results showed that the chiller cooling technology controlled the nutrient solution temperature in a reasonable range （（20 ± 1）℃） and promoted the growth and dry matter accumulation of Luosheng No.3, instead of affecting the quality. In short, the chiller cooling technology is applicable to the temperature regulation of nutrient solu- tion in hydroponics over summer.
基金The 973 Program Project of China under contract No. 2012CB956000the National Natural Science Foundation of China under contract Nos 40888001 and 41176019the Qingdao Municipal under contract No.10-3-3-38jh
文摘Using conductivity-Temperature-depth data of a recent cruise during July 22-28, 2008 and historical data, it is found that temperature inversions occur from time to time in the Huanghai Sea（Yellow Sea） cold water mass （HSCWM） in summer. The temperature inversions are produced by the movement of the fresh and cold HSCWM masses above the warm and saline Huanghai Sea Warm Current water at the central bottom of the Huanghai Sea Trough. The non-homogeneous profiles of the temperature and the salinity suggest that vertical mixing in the HSCWM, which is of great importance to the circulation in the Huanghai Sea in summer, is weak. Trajectories of satellite-tracked surface drifters suggest that waters in the northern reach of the Huanghai Sea move southward along the 40-50 m isobaths and descend into the southern Huanghai Sea to form the western core of the HSCWM.
文摘短命植物是荒漠生态系统重要的植物类群,其具有多样化的生境,且很多种类还具有异时萌发特性。植物生物量积累和分配能体现其对环境的响应与适应性特征,因此,研究不同环境条件下短命植物生物量分配格局有助于进一步了解短命植物的生存策略。以裸沙春萌(Bare Sand-Spring Germination,BS)、藻结皮春萌(Algal-Spring Germination,AS)、地衣结皮春萌(Lichen-Spring Germination,LS)3种自然结皮生境中萌发的尖喙牻牛儿苗春萌株及裸沙区夏季萌发(Summer Germination in Bare Sand,SG)的尖喙牻牛儿苗夏萌株为研究对象,采用全株挖掘法获取地上和地下生物量,系统对比分析了4个类型间植株生物量分配及异速生长关系的差异性,以探究其资源分配策略的变异性和保守型。结果表明:(1)尖喙牻牛儿苗单株地上、地下及总生物量总体表现为BS>AS>LS=SG的格局,其根冠比则呈SG=LS=AS>BS的特征。(2)BS和SG类型植株地上与地下生物量间为等速生长关系,而AS和LS生境为异速生长关系,但4个类型具有共同的异速生长指数(0.8843)。(3)AS和LS生境尖喙牻牛儿苗根冠比随个体增大均呈异速减小趋势,而BS和SG类型植株根冠比则保持相对恒定。可见,尖喙牻牛儿苗生物量分配会受到外界环境及个体发育的影响,并呈现明显的可塑性,在一定程度上反映了其资源分配的保守性与可塑性的权衡。
基金supported by the National Natural Science Foundation of China(Nos.40502015,40872202,and40930210)the 111 Project of China(No.B08030)
文摘Although Pleistocene red paleosols are widely distributed in South China, paleoenviron-mental interpretation has proved difficult because of intense weathering. Here we combine data from molecular fossil and magnetic properties to reconstruct a record of changes in pedogenic intensity for red paleosols in Southeast China. Depth distribution pattern of magnetic properties indicates that lower （higher） χ but higher （lower） values of HIRM （hard isothermal remanent magnetization） and SIRM （saturation isothermal remanent magnetization）/χ has tight relationship with the intensity of pedogenesis,especially the occurrence of well-developed net-like veins, which is absolutely responsible for the presence of anti-ferromagnetic minerals at the cost of fine-grained SP （superparamagnetic）/SD （single domain） ferrimagnetic minerals. The carbon distribution pattern of n-alkanes, n-alkanols, and n-alkanoic acids reflects the predominant contributions of microorganisms to the organic matter during pedogenesis, which provide direct evidence for strong microbial activities in response to theextremely hot-humid condition while white coarse net-like veins occurrence. Our results demonstrate that the presence of the enhanced East Asia summer monsoon has played a key role in the oxide-dominated weathering regime, and pedogenesis, and microbial activities. Changes in molecular ratios and magnetic properties are used to show that red paleosols have undergone three stages of soil formation in striking response to the evolution of the East Asia summer monsoon： （1） the most effective since the Middle Pleistocene; （2） moderately effective since 270 ka or so; （3） least effective since the last glacial. Our research provides important evidence to understand how red paleosols espond to global change since the Middle Pleistocene.
