不同DFT装置对生菜产量和品质的影响

为经济解决DFT栽培中根际溶氧问题，试验设计了4种结构特点不同的DFT装置，以意大利耐抽苔生菜为试验对象，研究不同DFT装置对生菜产量和品质的影响。结果表明，循环浮板法(CFS)栽培能够稳定供给植株生长所需要的养分和氧气，生菜产量最高，品质较好；支撑浮板法(SFS)栽培虽然不能使营养液中的溶氧达到理想水平，但暴露在空气中的根系可以吸收空气中的氧气，植株生长良好，维生素C含量最高，硝酸盐含量最低，与其他3种处理的差异达极显著水平；浮板法(FS)和动态液位法(DSS)中生菜产量相对较低，要想合理地应用这两种栽培方式，还需要对其结构和系统设计中的某些参数进行修改和设定。综合生菜产量因子与商品性状，支撑浮板法是最适宜的DFT方式。     

施肥量对醋糟基质栽培生菜的影响

研究了5种施肥量处理[正常施肥量的0 (0 s)、1/8 (1/8 s)、1/4 (1/4 s)、1/2( 1/2 s)和1(1 s)单位]对醋糟混合基质栽培生菜生长以及品质的影响.结果表明,1/4单位施肥量(1/4 s)处理下醋糟基质的pH和EC值变化较其他处理平稳.1/4单位施肥量(1/4 s)处理下生菜茎粗、产量、根鲜重、叶鲜重最大,而1个单位施肥量(1 s)处理下上述指标最小.对采收时生菜品质的分析表明,生菜叶片内的硝酸盐含量随着施肥量的增加而迅速上升,1个单位施肥量(1 s)处理下生菜叶片中硝酸盐和可溶性蛋白含量最高,1/4单位施肥量(1/4s)处理下生菜叶片中可溶性糖含量最高.综合考虑产量和品质,采用1/4单位的配方(1/4 s)是适合醋糟基质栽培生菜的施肥配方.     

塑料大棚中不同灌水量上限对生菜生长、品质及生理特性的影响

以两个散叶生菜品种(弘农和绿领)为材料，研究了塑料大棚栽培条件下不同土壤含水量(分别为田间持水量的60%～100%、60%～90%、60%～80%、60%～70%)处理对生菜生长、品质和生理特性的影响。收获期测定的结果表明，以田间持水量的90%作为灌水量上限条件下生菜地上部干鲜质量、叶面积、叶片数均最高，田间持水量80％为灌水上限条件下生菜地上部的生长优于田间持水量100％为灌水上限处理。随着灌水量上限的降低，生菜可溶性糖、可溶性蛋白含量逐渐升高，田间持水量80％和70％为灌水量上限处理下的维生素C含量显著高于其他两个灌水量上限处理。田间持水量70％的灌水量上限处理下生菜叶片中的MDA(丙二醛)、SOD(超氧化物岐化酶)、CAT(过氧化氢酶)和Pro(脯氨酸)含量最高，膜脂过氧化程度最重。本试验的结果表明，以田间持水量90％为灌水量上限处理下生菜的产量最高，综合不同灌水上限处理对产量和品质的影响，认为田间持水量80％的灌水量上限处理是最适合生菜生长的灌水处理。     

营养液浓度对水培生菜生长和硝酸盐积累的影响

该文研究了4种营养液浓度处理(山崎生菜配方的1/4(1/4s)、1/2(1/2s)、1(1s)和2(2s)单位)对水培生菜(品种为“弘农”和“绿领”)生长、硝酸盐积累和品质的影响。结果表明,1/2单位营养液浓度处理下生菜地上部和根的鲜重、叶长和叶宽最大,而2个单位营养液浓度处理下上述指标最小。不同营养液浓度处理下叶片硝酸盐积累的高低顺序为2s>1s>1/2s>1/4s,2个单位营养液浓度处理下生菜生长发育后期叶片中的SOD活性和M DA含量最高。对采收时生菜品质的分析表明,生菜体内的硝酸盐含量随着营养液浓度的增加而迅速上升,2个单位营养液浓度处理下生菜叶片中硝酸盐、可溶性糖和可溶性蛋白质R含量最高。综合考虑产量和品质,采用1/2单位的山崎生菜配方是适合生菜水培的营养液配方。     

沼液施用方式对两种叶菜品质及栽培环境的影响

为使沼液和现代灌溉装置相结合应用于温室叶菜栽培,以生菜和小白菜为试验材料,研究了滴灌、喷灌2种施肥方式与4种沼液施用浓度对叶菜品质、产量及栽培环境的影响。结果表明,滴灌和喷灌沼液比例均以V(沼液)∶V(水)=1∶4效果最佳。可以提高生菜和小白菜的产量、品质以及改善栽培基质的环境。滴灌条件下,小白菜和生菜的Vc的含量分别比对照增加了25.23%、40.00%,硝酸盐含量分别为238、122 mg·kg-1,显著低于对照处理;喷灌条件下,小白菜和生菜的Vc含量也分别比对照增加了18.98%、29.41%,硝酸盐含量也显著降低;并且两种叶菜叶片中重金属的含量均低于农产品安全质量无公害蔬菜安全要求(GB 18406.1—2001)的标准。沼液作为营养来源没有造成基质中养分富集和重金属的积累,滴灌和喷灌沼液两种施肥方法的叶菜收获后基质的pH值和EC值都显著降低,重金属的含量低于土壤安全生产要求(GB 15618—1995)的标准。     

NFT栽培槽槽底形状对生菜生产效果的影响

以生菜为试材,研究了NFT栽培槽不同槽底形状对生菜生产效果的影响.试验结果表明NFT栽培槽不同波纹式槽底形状对生菜的生物积累量有显著影响,但对生菜的品质无显著影响,其中,以纵剖面是不等边三角形的波纹式槽底形状对生菜的植株开展度和产量的影响最为显著.在NFT栽培方式中,栽培槽底铺不铺无纺布对生菜产量有显著影响.综合生菜产量因子与商品性状,以[(6+14)×4]的纵剖面不等边波纹式栽培槽槽底形状最优.     

城市雨水对生菜产量品质与重金属含量的影响

作为都市农业灌溉用水,城市雨水对农产品食品安全和营养品质的影响深受关注。论文收集自然雨水(T1)、屋顶雨水(T2)和路面雨水(T3),静置沉淀后配置营养液进行水培生菜种植,测量生物产量、生理指标(叶绿素含量、净光合速率、根系活力)、营养指标(可溶性糖、可溶性蛋白、维生素C、硝酸盐)和元素含量(Ca、Fe、Mg、Zn、As、Cd、Pb),结果表明:城市雨水重金属含量低于国家标准,可以作为农业灌溉用水;雨水栽培生菜比自来水栽培生菜长势弱、产量低,路面雨水栽培生菜产量最低,单株干质量仅为3.57 g;雨水降低了生菜叶绿素含量和净光合速率,提高了生菜根系活力,屋顶雨水生菜和路面雨水生菜根系活力分别为3.17和4.08 mg/(g·h),雨水栽培生菜的根冠比大于自来水生菜;雨水栽培生菜蛋白质、糖类和Vc含量不比自来水栽培生菜低,自然雨水生菜蛋白质质量分数4.97 mg/g,路面雨水生菜可溶性糖含量1.00%,路面雨水生菜Vc含量1.52 mg/g,分别为各项指标的最高值;供试生菜硝酸盐含量分别为5.62、5.48、6.04和7.04 mg/g,都超过了国家标准3.00 mg/g,这与试验采用1倍剂量营养液和采用硝酸调节p H值有关;雨水生菜有益元素Ca、Mg含量高于自来水生菜,Fe含量低于自来水生菜,雨水生菜总体品质略好于自来水生菜;自来水、自然雨水、屋顶雨水和路面雨水栽培生菜含As量分别为5.83、4.10、4.53和4.60μg/kg,含Cd量分别为0.76、0.78、2.59和1.37μg/kg,含Pb量分别为102.37、118.63、151.53和123.37μg/kg,远小于国家限量值,满足食品安全要求。总之,利用城市雨水作为都市农业灌溉用水,作物长势弱,产量低,但营养品质略好,食品安全,将城市雨水作为都市农业灌溉用水是可行的。     

营养液浓度对水培生菜生长和硝酸盐积累的影响

该文研究了4种营养液浓度处理(山崎生菜配方的1/4(1/4s)、1/2(1/2s)、1(1s)和2(2s)单位)对水培生菜(品种为“弘农”和“绿领”)生长、硝酸盐积累和品质的影响。结果表明，1/2单位营养液浓度处理下生菜地上部和根的鲜重、叶长和叶宽最大，而2个单位营养液浓度处理下上述指标最小。不同营养液浓度处理下叶片硝酸盐积累的高低顺序为2s>1s>1/2s>1/4s，2个单位营养液浓度处理下生菜生长发育后期叶片中的SOD活性和MDA含量最高。对采收时生菜品质的分析表明，生菜体内的硝酸盐含量随着营养液浓度的增加而迅速上升，2个单位营养液浓度处理下生菜叶片中硝酸盐、可溶性糖和可溶性蛋白质R 含量最高。综合考虑产量和品质，采用1/2单位的山崎生菜配方是适合生菜水培的营养液配方。     

基质添加菌糠对几种蔬菜硝酸盐含量的影响

试验研究在栽培基质中添加不同比例的菌糠对蔬菜硝酸盐积累的影响,结果初步表明:(1)施用菌糠可以显著提高紫叶生菜、菠菜和菜心的产量,尤其是菜心,但过量施用会阻碍植株的生长。(2)施用菌糠可显著降低紫叶生菜、菜心和菠菜的硝酸盐含量,但过量施用反而使这些蔬菜更易在可食部分积累硝酸盐。(3)施用菌糠可显著降低紫叶生菜、菜心和菠菜的亚硝酸盐含量,但过量施用会导致可食部分亚硝酸盐含量的增加。(4)珍珠岩、草炭土、菌糠之比为4∶2∶4的混合基质配方是提高紫叶生菜、菜心和菠菜产量,降低可食部分硝酸盐含量的最佳栽培基质配方。     

NFT栽培槽槽底形状对生菜生产效果的影响

以生菜为试材，研究了NFT栽培槽不同槽底形状对生菜生产效果的影响。试验结果表明：NFT栽培槽不同波纹式槽底形状对生菜的生物积累量有显著影响，但对生菜的品质无显著影响，其中，以纵剖面是不等边三角形的波纹式槽底形状对生菜的植株开展度和产量的影响最为显著。在NFT栽培方式中，栽培槽底铺不铺无纺布对生菜产量有显著影响。综合生菜产量因子与商品性状，以［(6+14)×4］的纵剖面不等边波纹式栽培槽槽底形状最优。     

多功能水耕栽培装置营养液自控系统的研制及应用效果(简报)

多功能水耕栽培系统由栽培床、封闭式循环供液系统、液温调控、增氧设施以及营养液自动检测与控制系统组成。经过半年运行试验结果表明:该系统可提高水耕栽培床的封闭性能,实现了对溶解氧的自动检测与控制和营养液数据的自动采集和自动控制功能。该系统解决了传统开放式水耕栽培装置营养液利用率低、控制水平差、污染严重、水资源浪费大等缺点,可有效提高产品的产量和品质。     

Einfluß der NO3- bzw. NH4-Ernährung auf Ertrag und Nitratgehalt von Spinat und Kopfsalat

Influence of NO₃ and NH₄-nutrition on yield and nitrate content of spinach and lettuce Field and pot experiments were conducted in order to study the effect of N-supply (N_min + N-fertilization) and partial and complete NH₄-nutrition on yield and nitrate content of spinach and lettuce. The highest yields were obtained when the N-supply of spring spinach was 250 kg N/ha, autumn spinach 200 kg N/ha and lettuce 120 kg N/ha. Nitrate content of plants could be diminished by reducing N-supply. However, if N-supply is below the optimum value yield depressions are inevitable. NH₄-nutrition reduced in both species nitrate content. But, spinach yield was reduced heavily. Very low nitrate content of plants occured, when N-nutrition of plants cultivated in nutrient solution, was changed from NO₃ to NH₄ during the last days before harvest. Herewith similar weights and head quality were obtained as with permanent NO₃-nutrition.     

间作对气雾培生菜生长和硝酸盐积累的影响

该文对生菜与樱桃萝卜间作和生菜单作模式下气雾培生菜相关指标进行了对比研究,并结合营养液中矿质元素含量的变化规律进一步分析了生菜与樱桃萝卜间作模式下生菜地上部分硝酸盐积累的主因素。结果表明：生菜与樱桃萝卜间作有利于提高生菜地上部分鲜质量,促进生菜叶片的展开以及生菜植株根总长度、根系表面积和根系体积等植株根系形态学参数的增大;生菜与樱桃萝卜间作增加了生菜SPAD值、净光合速率、气孔导度和蒸腾速率等光合指标,而对胞间CO2浓度无明显规律性影响;生菜与樱桃萝卜间作不同程度地降低了生菜硝酸盐含量,随着气雾培时间的推进,总体呈先降低后增加的趋势,而硝酸还原酶活性的变化趋势与硝酸盐含量的变化趋势相反;进行相关性分析得出,生菜与樱桃萝卜间作模式下生菜硝酸盐含量降低主要是由于硝酸还原酶活性的增加导致的,并且营养液中硝态氮消耗量、铵硝比和锰消耗量对硝酸还原酶活性影响较大,相关系数分别为0.882、0.762和0.851。研究结果揭示了生菜与樱桃萝卜间作模式对气雾培生菜生长和硝酸盐积累的影响,并探究了该模式下生菜硝酸盐积累的主因素,为生菜与樱桃萝卜间作模式的作用机理研究提供一定的理论基础。     

INTERACTION BETWEEN WATER ALKALINITY AND NUTRIENT SOLUTION PH ON THE VEGETATIVE GROWTH,CHLOROPHYLL FLUORESCENCE AND LEAF MAGNESIUM,IRON, MANGANESE,AND ZINC CONCENTRATIONS IN LETTUCE

Alkalinity of water is considered critical for plant growth. Interactions between water alkalinity and solution pH on lettuce were investigated. Seeds of romaine type lettuce were sown in pots containing perlite and irrigated with a high alkaline nutrient solution at four pH values (5, 6, 7, and 8). Considering the high amount of Fv/Fm at pH 5; higher shoot growth (at pH 5) could be due to the improvement of the efficiency of the photosynthesis apparatus of plants and consequently higher photochemical quantum yield. Although, magnesium (Mg) concentration in leaves increased with elevating pH up to 7 and then decreased at 8, but iron (Fe), manganese (Mn), and zinc (Zn) concentrations decreased at higher solution pH levels, constantly. In commercial lettuce production in which water with high pH and carbonate species is normally used, it is better to use safe acids to reduce the pH in nutrient solutions to 5.     

INCIDENCE OF LETTUCE TIPBURN AS RELATED TO HYDROPONIC SYSTEM AND CULTIVAR

The incidence of tipburn was studied by growing late winter and spring lettuce cultivars in two consecutive experiments, in hydroponics, either with Deep Flow Technique (DFT) or on solid growth substrates, in Messinia, NW, Greece. Both experiments showed that the fresh marketable yield of lettuce in DFT was approximately twice as great compared to that of plants grown on solid substrates. Tipburn injury was not observed in the late winter experiment whereas it was severe in the spring one. In particular, lettuce grown with DFT in the spring presented significantly greater level of injury whereas when grown on perlite the least. Their shoot calcium concentration was significantly lowest whereas when grown on perlite the highest. Between the two spring cultivars included, ‘Merlin’, which presented the greatest injury, also had significantly higher shoot fresh weight, lower root/shoot ratio, higher tissue water content, and lower nitrogen, potassium, calcium, and magnesium concentrations compared to ‘Gramsi’.     

营养液供液高度对水培生菜生长及矿质元素吸收的影响

在密闭植物工厂条件内,设置5种营养液高度（2、3、4、5、6cm）水培种植生菜,以探究霍格兰（Hoagland）配方营养液不同供液高度对生菜十种矿质元素（K、P、Ca、Mg、Na、Fe、Mn、Zn、Cu、S）吸收及积累的影响。结果表明：生菜地上部生物量以及光合色素含量均在4cm供液高度处理下最大,而地下部生物量以及根长均随着营养液供液高度的增加而升高;生菜地上部十种矿质元素的含量均在供液高度6cm处理下最大,而矿质元素在生菜中的单株累积量则表现为Fe、Mn元素在6cm供液高度下最大,Ca、Mg、Na、Zn、Cu、S元素在4cm供液高度下最大,K、P元素在5cm供液高度下最大。因此,实际生产中可以通过调节水培生菜营养液的供液高度,以达到提高生菜产量或生产功能性蔬菜的目的。     

Effect of NO3 and NH4 concentrations in nutrient solution on yield and nitrate concentration in seasonally grown leaf lettuce

The effect of suboptimal supply of nitrogen (N) and of replacing nitrate in the nutrient solution with ammonia on growth, yield, and nitrate concentration in green and red leaf lettuce was evaluated over two seasons (autumn and spring) using multiple regression analysis. The plants were grown in a greenhouse on a Nutrient Film Technique (NFT) system. Nitrogen concentrations in the nutrient solution were either 3?mM or 12?mM, and the form of N was varied as follows: 100% NO₃, 50% NO₃?+?50% NH₄, and 100% NH₄. In both seasons, the biomass (fresh weight) of lettuce heads increased with increasing NO₃ concentrations and in autumn, NO₃ even at 1.5?mM was sufficient for high yield. However, head dry weight was affected neither by the season nor by changes in the composition of the nutrient solution. The concentration of NO₃ had no effect on root dry weight, but it decreased at higher concentrations of NH₄. The number of leaves increased as the ratio of NO₃ to NH₄ in the nutrient solution increased and was higher in autumn because of the longer growth period. Increasing the concentration of NO₃ in nutrient solution increased both total N and nitrate concentration in lettuce heads (dry weight) but decreased the concentration of total C. Also, leaf nitrate concentration was lower in spring than in autumn and decreased with increasing NH₄ concentration. Nitrogen utilization efficiency was maximum when NH₄ levels in the nutrient solution were either 0% or 50% irrespective of the season. Our results thus show that suboptimal N supply in autumn will not affect lettuce yield, and that nitrate concentration in leaves is lower when NH₄ concentrations in nutrient solution are higher and also much lower in red lettuce than in green lettuce.