喷硒时期与浓度对红富士苹果果实品质及各部位全硒和有机态硒含量的影响

本试验通过叶面喷施外源硒肥、原子荧光法测定样品硒含量,研究不同硒喷施浓度对果树各部位无机硒含量、硒有机化程度及果实品质的影响,筛选红富士苹果的最佳施硒方案。结果表明, 1）在花期和幼果期叶面施硒效果较为稳定,叶片和果实中硒的有机化程度高。在接近果实着色期或采收期叶面施硒,虽然果实中总硒量较高,但硒的有机化程度较低。2）相同喷施浓度下,树体各器官硒含量顺序依次为叶＞枝＞果＞根,果树地上部分配的硒占较大比例。3）叶面喷施硒可增加果实中可溶性固形物、可溶性糖和Vc 含量,从而改善了果实风味,但降低了果实硬度,影响其贮藏运输品质。4）红富士苹果以在5、6、7月中旬喷施 3 次100 mg/L 亚硒酸钠效果最佳,此时叶片中总硒含量为2728.30 g/kg, FW,有机化程度达85.71%。各项果实品质指标佳,平均单果重达256.8 g。果实总硒含量为10.10 g/kg, FW,有机化程度为87.72%。     

叶面喷施硒肥对灰枣果实硒含量的影响

以喀什灰枣为对象,于枣树开花期、坐果期叶面喷施硒肥,研究不同时期、不同硒肥及不同浓度处理下, 叶面喷施硒肥对枣果中硒含量的影响,分析硒含量在枣果发育期的变化过程,筛选出硒肥喷施的适宜浓度和时期, 明确富硒灰枣生产的适宜施肥管理措施。结果表明,叶面喷施硒肥可显著提高灰枣果实硒含量,达到富硒效果, 且随着施硒量的增加呈一直增加的趋势;果实硒含量在果实膨大期达到最大值,之后在完熟期有所降低;在枣果 完熟后期,坐果期施用无机硒肥处理果实硒含量均高于开花期,从果实对硒的吸收来看,说明灰枣无论喷施无机 硒肥还是有机硒肥,施用硒肥的关键时期均为坐果期。在枣果完熟后期,坐果期喷施无机硒肥 40 mg/L 处理下对 果实硒含量增加效果显著,硒含量达到 0.2698 mg/kg;坐果期喷施有机硒肥 32 mg/L 处理下对果实硒含量增加效果 显著,硒含量达到 0.2226 mg/L,两种硒肥处理下果实硒含量均达到了富硒农产品国家标准。综上所述,坐果期喷 施 40 mg/L 无机硒肥或 32 mg/L 有机硒肥最符合当地生产需求。     

喷施不同叶面肥对冬枣品质的影响

[目的]利用"沾化冬枣",在陕西省科学院大荔现代农业科技示范基地露地栽培条件下,研究叶面喷施SOD,富硒肥和噻苯隆对冬枣品质的影响。[方法]利用钼蓝比色法、氢氧化钠滴定法和紫外分光光度法等方法测定不同处理之下果实品质指标。[结果](1)叶面喷SOD肥可显著提高冬枣可溶性糖、可溶性固形物含量,降低Vc和有机酸含量,降低采摘后15和30d的果实密度;显著提高了采摘期和采后24d的果实红色度,提早果实转色,促使冬枣提前上市,降低烂果率。(2)喷富硒叶面肥可显著提高果实中硒含量,提高果实可溶性糖含量,降低Vc和有机酸含量。(3)叶面喷施噻苯隆混合叶面肥,可提高冬枣可溶性糖、可溶性固形物和有机酸含量,降低采摘后15d的果实密度,但采摘后30d果实密度大于对照;推迟果实转色,促使冬枣延后上市,延长了冬枣市场供应期,降低烂果率,提高经济效益。[结论]叶面喷施SOD,富硒肥和噻苯隆对冬枣品质产生了重要影响,它们在一定程度上提高了果实品质,其中喷施富硒肥可以提高果实的营养品质和保健功能,喷施SOD和噻苯隆则分别利于果实的提前和延后上市,延长冬枣货架期,提高经济效益。     

外源硒对芒果硒含量及果实营养品质的影响

探讨叶面喷施和土施外源硒对芒果叶片和果实硒含量、果实矿质元素含量及营养品质的影响，以期为富硒芒果的安全生产提供理论依据和技术支持。以“桂热 82号”芒果为试材，叶面喷施以亚硒酸钠为硒源，设置0.0、25.0、50.0、100.0、150.0和 200.0 mg/L 6个浓度水平，于生理落果结束后，每 15 d喷施一次，连喷 2次。土施设置亚硒酸钠处理和硒酸钠处理，施肥量为 10 g/株，于花期沟施。结果表明，芒果叶片和果实中的硒含量随着叶面喷硒浓度的增加而递增。叶面喷施 50 mg/L亚硒酸钠可显著提高果实 Vc含量，200 mg/L亚硒酸钠可显著提高果实K、可滴定酸含量，100～ 200 mg/L亚硒酸钠可显著降低果实Zn、Ca含量。土施相同量的亚硒酸钠和硒酸钠均可显著提高芒果叶片和果实硒含量。土施硒酸钠叶片和果实硒含量显著高于亚硒酸钠。土施 10 g/株亚硒酸钠显著降低果实 Ca、Mg含量，土施 10 g/株硒酸钠显著提高果实 K、Vc含量，降低果实 Ca含量。叶面喷硒和土壤施硒均可显著提高芒果叶片和果实硒含量，其中叶面喷硒提高幅度远大于土壤施硒提高幅度。土施硒酸钠比亚硒酸钠更容易被芒果吸收。富硒芒果生产上推荐叶面喷施 25.0～ 50.0 mg/L亚硒酸钠，或者土施 10 g/株硒酸钠。     

施用氨基酸硒肥对梨体内硒含量的影响

【目的】以华酥梨为试材,研究了不同施肥方式施用氨基酸硒肥对梨体内硒含量的影响,以期为氨基酸硒肥的合理施用及富硒梨生产提供理论依据。【方法】试验设置叶面喷施和土壤施入两种施肥方式,每种施肥方式设置4个处理,其中土壤施入设每株施入30 m L(900 mg/plant)、60 m L(1800 mg/plant)、90 m L(2700 mg/plant)和120m L(3600 mg/plant),叶面喷施设每株喷施300倍(150.0 mg/plant)、400倍(112.5 mg/plant)、600倍(75.0mg/plant)和1000倍(45.0 mg/plant)。叶面喷施从盛花期开始,每隔15天喷施一次,直至果实成熟前15天左右停止,共喷施7次。土壤施入前将氨基酸硒肥兑清水,均匀浇于施肥坑中,于盛花期一次性施入。分别于花后15 d、30 d、45 d、60 d、75 d、90 d取果实和叶片,并将果实解析为果皮、果肉和果心3个部分,分别测定硒含量。【结果】1)两种施肥方式均可极显著提高梨果实和叶片中的硒含量。2)喷施氨基酸硒肥后梨果实和叶片中硒含量在发育初期最高,不同部位硒含量的变化趋势不同,而土施氨基酸硒肥后梨果实和叶片中硒含量均呈现逐步升高的趋势,并在采收时达到最高。3)施肥后单果硒吸收量呈现上升的趋势,花后30 45 d为果实吸收硒的关键期。4)梨叶片的硒含量高于果肉,而且含量高低顺序不受施肥的影响,但果皮、果肉和果心3个部位硒含量的高低顺序与施肥方式有关,喷施氨基酸硒肥可以改变硒在果实各部位含量的高低顺序,而土施氨基酸硒肥对其没有影响。5)施肥量较小时,果肉和叶片中硒含量与施肥量呈正相关,但当施肥时有效硒含量超过2700 mg/plant时,硒含量反而会下降。【结论】施用氨基酸硒肥影响着梨树体内硒含量。与土施相比,喷施处理后梨对硒的吸收快、吸收和积累效率高、硒利用率高,因此,喷施氨基酸硒肥是富硒梨生产最经济有效的方法,施肥量以有效硒含量不超过2700mg/plant为宜。     

不同时期叶面喷硒对冬枣含硒量与品质的影响

为了筛选冬枣(Zizyphus jujuba Mill. var. Dongzao)的最佳施硒方案,通过在展叶期、幼果期、果实膨大期、白熟期分别进行一次性叶面喷施亚硒酸钠溶液(含硒量为45 mg·L~(-1),施硒量为27 mg·株~(-1)),研究不同时期施硒对冬枣叶片和果实的硒含量、硒有机化程度以及果实品质的影响。结果表明:在果实膨大期或白熟期叶面喷施硒溶液后,叶片和果实的总硒含量均得到显著提高,其中果实膨大期喷硒使总硒和有机硒含量增幅最大,冬枣果实含硒量由25μg·kg~(-1)提高到76μg·kg~(-1)。不同时期叶面喷硒对冬枣果实品质的作用效果不尽相同,果实膨大期施硒对冬枣品质的改善效果最佳,此时冬枣果实中的可溶性固形物、可溶性糖、维生素C、总黄酮含量和糖酸比均达到最高值,分别较对照显著提高了13.30%、17.17%、16.33%、29.17%和28.89%。综合研究结果表明,生产富硒冬枣以在果实膨大期一次叶面喷硒的效果最佳。     

氨基酸硒液体肥在设施桃上的应用效果

以设施栽培的4年生中油4号油桃和春雪毛桃为试材,对氨基酸硒的应用效果进行了研究。结果表明:施用氨基酸硒液体肥显著增加栅栏组织厚度和叶片厚度及比叶重,改善桃树的叶片质量;显著促进叶绿素和类胡萝卜素等光合色素的合成,提高净光合速率,施用氨基酸硒液体肥处理净光合速率是对照的1.22～1.50倍;显著增加产量,施用氨基酸硒液体肥处理比对照高2.836～8.145 t/hm2;显著增加果实可溶性固形物和可溶性糖含量及糖酸比,改善果实品质;显著提高果实的Vc含量、超氧化物歧化酶(SOD)活性和果实硒含量,提高果实的营养与保健品质。与土施相比,叶面喷施效果更佳且经济。     

叶面喷施纳米硒肥对金丝小枣产量和品质的影响

硒是人体所必需的微量元素,随着人们对硒产品认识程度逐渐加深,富硒食品在市场上出现的越来越多。以乐陵金丝小枣为对象,于枣果幼果期、果实膨大期、转色期叶面喷施纳米硒肥,探究不同浓度梯度(0、4.8、9.6、14.4 mL/L)纳米硒肥对枣产量和品质的影响。结果表明,叶面喷施纳米硒肥可显著增加金丝小枣的产量和品质,随着喷施硒浓度的增加,金丝小枣枣果中硒含量逐渐增加,但产量出现先增加后降低的趋势,叶面喷施硒肥可显著增加可溶性固形物含量、维C含量以及枣果中和叶片中矿质元素含量,以9.6 mL/L浓度处理下效果最佳,产量增加33.0%,可溶性固形物显著增加8.4%,维C含量显著增加53.5%,且枣果中硒含量达0.28 mg/kg,较空白对照显著增加171.8%,矿质元素磷、钾、钙、镁、硼、铁的含量增加最为显著。综合分析,叶面喷施纳米硒肥浓度为9.6 mL/L时增产提质效果最佳。     

镁肥对葡萄叶片糖、淀粉和蛋白质及果实品质的影响

探讨大田条件下,施镁对缺镁葡萄叶片糖、淀粉和蛋白质及果实品质的影响,为葡萄科学施肥提供理论依据。采用裂区试验,主区设4个土施硫酸镁梯度,为0、112.5、150、187.5 kg/hm~2,副区设3个叶面喷施硫酸镁浓度,分别是0%、0.2%、0.4%。结果发现:土施和叶面喷施镁肥能够显著提高叶片镁含量,提升硝酸还原酶活性,增加可溶性蛋白和可溶性糖含量,并促进淀粉转运,减少其在叶片中的积累,最终增加果皮花色素含量,使果皮显著变红,并提高果实可溶性固形物含量,降低可滴定酸含量,提升了果实外在和内在品质。土施150 kg/hm~2同时叶面喷施0.4%硫酸镁肥时,叶片镁含量处于适量标准,硝酸还原酶活性高,叶片可溶性蛋白和糖含量高,果皮红,果实糖高酸低,施镁效果最好。     

叶面喷施硒肥对猕猴桃富硒和产量的影响

以红阳、东红猕猴桃为材料,在扬花坐果期和果实膨大期使用5种不同用量的叶面喷施用含硒肥料,对红阳和东红猕猴桃进行叶面喷施,观察叶面喷施对这2种猕猴桃含硒量及产量的影响。结果表明,叶面喷施各用量均能增加猕猴桃可食部位总硒含量,达到水果富硒标准要求,且平均增产5%～10%,而对照组的硒主要来源于土壤硒供给,多数集中于叶片,进入可食部位的少。     

Nitrogen Assimilatory Enzymes and Amino Acid Content in Inoculated Foliar Fertilized Pea Plants Grown at Reduced Molybdenum Concentration

ABSTRACT

A possibility to improve nitrogen assimilation in nitrogen fixing Molybdenum (Mo) deficient pea plants was shown. The influence of foliar supplied nutrients in addition to root nutrition resulted in reducing the unfavorable effects of inorganic nitrogen on nodule function and Mo deficiency on the nitrogen assimilatory enzymes. Inoculated pea plants were grown on liquid nutrient solution both with and without Mo. The following variants were tested: Mo supplied plants with root nutrition (F1 + Mo); Mo supplied plants with root and foliar nutrition (F2 + Mo); Mo deficient plants with root nutrition (F1 ? Mo); and Mo deficient plants with root and foliar nutrition (F2 ? Mo). Foliar application of nutrients had a positive effect on the glutamine synthetase and glutamate synthase enzyme activities in the roots and nodules of Mo deficient plants. It was found that the foliar fertilization reduced the inhibitory effect of Mo shortage on the aspartate/asparagine content in the pea shoots.     

生物炭与叶面硒肥联合施用对生菜吸收镉及土壤镉形态的影响

  目的  为探明生菜吸收富集镉的能力对生物炭与叶面硒肥的响应程度,抑制有毒有害元素镉的吸收。  方法  通过盆栽试验,以生菜为研究对象,在镉污染土壤中添加生物炭,并在生菜叶片上喷硒处理,探索了生物炭与叶面喷硒的联合施用对镉污染土壤理化指标（pH和有机碳）和土壤不同形态镉含量以及对生菜镉吸收累积的影响。  结果  ① 土壤中添加生物炭与叶面硒肥都可以有效降低生菜可食部镉含量,其中喷施低浓度硒的效果更好。当生物炭添加量为30 g kg?1,叶面喷硒浓度为1 mg L?1时,生菜地上部镉含量由0.314 mg kg?1降至0.049 mg kg?1,低于国家食品安全标准（GB 2762—2017）中规定的叶菜类镉限量值0.20 mg kg?1。② 镉胁迫下,添加生物炭与叶面硒肥的交互作用对生菜镉含量和镉富集与转运能力均产生了显著性的影响,相对于生菜根部镉含量,添加生物炭的效应高于叶面硒肥的效应,而对于地上部镉含量,叶面硒肥的效应高于添加生物炭的效应。③ 生物炭添加可通过改善土壤pH和有机碳含量降低酸可提取态、可还原态、可氧化态镉的比例,增加残渣态镉的比例,从而有效地降低生菜对土壤中镉的吸收累积,减少生菜中镉含量。  结论  综合来看,生物炭与叶面硒肥联合施用可以降低生菜镉含量,其效果明显高于两者单独施用的效果,为无公害蔬菜的种植提供理论指导。     

土壤改良剂与叶面喷硒联合阻控对小白菜吸收镉的影响

为探究改良剂与叶面喷硒（Se）联合阻控减轻农产品受镉（Cd）毒害的效果,采用土壤培养及盆栽试验的方法,筛选不同用量的牛粪（7.5、15 g kg?1）与石灰（1、2、3、4、5 g kg?1）配施钝化土壤Cd有效性的最优处理,并探讨改良剂与叶面喷Se（1、2、4、8 mg L?1）联合阻控对不同程度Cd污染土壤（0.5、3、6 mg kg?1）中小白菜吸收Cd的影响。结果表明:（1）与未施改良剂处理相比,7.5 g kg?1牛粪与 5 g kg?1石灰配施对土壤Cd的钝化效果最显著,土壤有效Cd含量降低了37.9%。（2）与单施改良剂相比,施用改良剂与叶面喷Se显著抑制了小白菜对Cd的吸收,其中在中轻度污染土壤中（0.5 和 3 mg kg?1 Cd）叶面喷施 4 mg L?1 Se使小白菜Cd含量分别降低了 12.9% 和 78.7%,丙二醛含量分别降低了29.9% 和 60.6%;在重度污染土壤中（6 mg kg?1 Cd）叶面喷施 8 mg L?1 Se使小白菜Cd含量降低了 81.4%,丙二醛含量降低了71.9%;叶面喷Se使小白菜的抗氧化酶活性和谷胱甘肽含量均有不同程度的增加。     

铜基叶面肥及控释肥对辣椒生长发育和叶片保护酶等生理特性的影响

【目的】针对辣椒喜肥、耐肥、对水分要求严格的特点,采用铜基叶面肥、控释肥两种新技术,研究了叶面喷施铜基叶面肥和土施控释肥对辣椒产量、矿质养分在植株体内的分布、保护性酶活性以及果实品质的影响,为提高果蔬产量和改善品质提供理论依据。【方法】分别于2011年4~11月和2012年3~9月,在山东农业大学南校区土肥资源高效利用国家工程实验室新型肥料中试基地, 以赤峰牛角王为供试辣椒品种设置肥料盆栽试验,试验设8个处理: 1）喷清水土壤不施肥对照（CKW- NF）;2）喷清水+土施普通肥（CKW+CCF）; 3）喷清水+土施控释肥（CKW+CRF）; 4）喷清水+土施控释肥+保水剂（CKW+CRF+W）; 5）喷铜基叶面肥土壤不施肥（CBFF-NF）; 6）喷铜基叶面肥+土施普通肥（CBFF+CCF）; 7）喷铜基叶面肥+土施控释肥（CBFF+CRF）;8）喷铜基叶面肥+土施控释肥+保水剂（CBFF+CRF+W）。采用称重法测定辣椒产量,于收获期取果实及叶片鲜样用于果实品质和生理生化指标测定,植株各部位干样用于微量元素测定。【结果】1）两年内喷施铜基叶面肥和土施控释肥均能提高辣椒产量,其中叶面喷施铜基叶面肥+土施控释肥+保水剂（CBFF+CRF+W）组合对辣椒产量的提高幅度最大,与CKW+CRF+W相比2011年增产24.1%,2012年增产29.0%。2）相同的土壤施肥条件下,与喷清水相比,喷施铜基叶面肥能够显著提高辣椒植株体内的铜浓度。其中,土施控释肥加保水剂基础上喷施铜基叶面肥处理的辣椒果实中铜浓度比叶面喷清水显著提高了103.9%;土施控释肥条件下,叶面喷施铜基叶面肥较喷清水处理下的果实铜浓度增加了41.5%。3）喷施铜基叶面肥后,辣椒叶片的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性升高,而过氧化氢酶（CAT）活性下降。CBFF+CRF+W处理下的辣椒叶片SOD活性较CKW+CRF+W处理显著提高了26.6%,CBFF+CRF+W组合的叶片的POD活性和CAT活性与CKW+CRF差异显著。4）与喷清水处理相比,无论在土壤施用控释肥还是土壤施用控释肥+保水剂的条件下,叶面喷施铜基叶面肥均使辣椒果实可溶性蛋白和维生素C的含量显著提高,其增加幅度在12.8%~178.4%。【结论】综合考虑几种肥料组合,叶面喷施铜基叶面肥和土施控释肥可在一定程度上调控植株微量元素的积累,改善辣椒营养品质,提高辣椒产量。     

土壤性质对土壤–水稻系统中硒迁移的影响

采集浙江省北部水稻种植区成熟期水稻和对应的土壤样品,分析土壤中硒(Se)总量和7种形态Se的含量以及水稻根、茎、叶、谷各部位的Se含量。结果表明:研究区土壤Se平均含量0.344 mg/kg,达到中Se土壤水平,并且与土壤有机质含量呈显著正相关。7种Se形态中,强有机结合态和腐植酸结合态是主要的两种形态,占Se全量的75.92%;离子交换态、水溶态的含量在1.7%左右;碳酸盐结合态为3.2%。水稻根部富集了大部分的Se(73%),其各部位中Se含量随根、叶、茎、谷的顺序依次减少。将土壤按有机质和p H的大小进行分区分析后发现,当有机质含量小于25 g/kg时,土壤铁锰氧化物结合态Se与水稻根部Se呈显著正相关;当有机质含量大于35 g/kg时,土壤铁锰氧化物结合态Se与谷Se呈显著正相关;当p H7时,碳酸盐态Se与谷Se呈显著负相关。水溶态Se和离子交换态Se与水稻各部位Se含量之间并未呈现明显的相关性。水稻各器官Se含量受土壤p H、有机质含量、各形态Se含量等土壤性质的交互作用影响。     

Effect of foliar fertilization of potassium on yield,quality, and nutrient uptake of groundnut

Abstract

Groundnut (Arachis hypogae L.) is the most important oilseed crop of India and it is abundantly grown under rainfed conditions in vertisols of Western India. The objective of this work was to study the effect of potassium (K) basal and foliar fertilization on yield, nutrient concentration in tissue and quality parameters of groundnut. Two varieties, GAUG‐1 (bunch type) and GAUG‐10 (spreading type) were grown during Kharif (rainfed) and Rabi (irrigated) seasons at Junagadh, Gujarat. The experiment compared two foliarapplied K fertilizers (KCl and K₂SO₄) at two different doses (0.5 and 1.0%) with basal KCl application (0 and 50 kg K₂O ha^?1). Field soil was highly calcareous (pH 8.2, NH₄OAc extractable K 188 kg ha^?1 with 40% lime reserve) Vertic ustochrept. The results showed a significant response in pod yield with foliar and soil‐applied potassium as compared to the control treatment. Pod yields were significantly higher when basal and foliar applications were combined. The best results were achieved with foliar application of 1% KCl together with a basal fertilization with 50 kg K₂O ha^?1. Response to foliar‐applied K was higher in rainfed kharif crop than in irrigated rabi crop. Groundnut variety GAUG‐10 out yielded GAUG‐1. Foliar K application increased plant tissue concentration of K. Foliar fertilization with KCl and K₂SO₄ did not cause leaf burn. Potassium application improved the crop harvest index and grain quality parameters of boldness, protein and oil contents. Response to K in quality parameters of protein and oil contents of seed was more consistent with foliar applied K₂SO₄ . The results confirmed that the practice of foliar K nutrition when used as a supplement and not a substitute for standard soil fertilization, is beneficial for groundnut crop in Western India.     

Response of Mature Phosphorus-Deficient Apple Trees to Phosphorus Fertilization and Liming

ABSTRACT

The aim of the study was to examine response of mature phosphorus (P) deficient apple (Malus domestica Borkh.) trees to phosphorus fertilization and liming. The experiment was carried out during 2003–2005 in a commercial orchard in Central Poland on ‘Jonagold’ apple trees/M.26 planted in 1996 on a coarse-textured soil with low both pH (4.6) and organic matter (1.2%). Calcium-lactate soluble phosphorus concentration in the soil was within an optimal range despite appearance of leaf phosphorus deficiency symptoms. Soil and foliar applications of phosphorus, and soil liming were applied. Soil phosphorus fertilization was made in the first year of the experimental at a rate of 100 kg P per ha as triple superphosphate. Foliar sprays of a soluble compound containing organic phosphorus were performed 5 times per season at 2-week intervals, starting 4 weeks after full bloom. Soil liming was applied in the fall 2002 at a rate of 1100 kg Ca ha^?1 as hydrated lime. Additional combination as soil phosphorus fertilization plus liming was also applied. Plots unsupplied with phosphorus and lime served as a control. The results showed that liming and liming plus soil P application increased soil pH, and phosphatase activity in the soil, and improved phosphorus nutrition, tree vigor, yield, fruit color, and firmness after storage; effect of these treatments was not found only in the first year of the study. In all years foliar phosphorus sprays improved phosphorus nutrition of apple trees, and fruit color and firmness after storage. In 2 out of 3 years foliar phosphorus application increased yield. The vegetative and reproductive responses of ‘Jonagold’ apple trees did not depend on soil phosphorus fertilization. It was concluded that maintaining an optimal pH of soils for apple trees limits the incidence of orchard phosphorus deficiency and that foliar phosphorus sprays should be applied in phosphorus-deficient apple orchards to improve yield, and fruit appearance and storability.     

叶面施硒对黑豆硒吸收转运特征及籽粒硒形态的影响

为了明确叶面喷施亚硒酸钠对黑豆硒吸收转运特征及籽粒硒形态的影响,采用小区试验在黑豆结荚兴盛期进行一次性叶面喷施亚硒酸钠(施硒量分别为0、6、12、18和24 mg·m^-2)处理,分析比较不同浓度亚硒酸钠处理下黑豆产量、各器官硒含量、籽粒有机硒转化率和品质性状的差异。结果表明,各施硒水平对黑豆各器官总硒含量均有提升作用,在24 mg·m^-2硒处理时各器官总硒含量最大,根、茎、荚和籽粒硒含量分别较对照提高了8.74、8.37、9.85和65.21倍,硒处理后各器官总硒含量呈现籽粒>根≈荚>茎的特点。籽粒中硒以有机硒形态存在,且有机硒转化率随着亚硒酸钠浓度的增加呈下降趋势,在0、6、12、18和24 mg·m^-2施硒处理时,有机硒含量分别为0.071 4、1.101 8、1.510 6、1.811 1和2.093 5 mg·kg^-1,有机硒转化率分别为94.52%、84.81%、70.30%、60.11%和52.43%。叶面喷施亚硒酸钠显著提高了黑豆籽粒蛋白质含量和分离蛋白硒含量,但对脂肪含量的影响较小,在24 mg·m^-2硒处理时蛋白质含量和分离蛋白硒含量分别较对照增加了2.4个百分点和117.35倍,分离蛋白硒含量占有机硒和总硒含量的比例分别为90.29%和47.39%。适宜浓度亚硒酸钠叶面喷施对黑豆产量具有促进作用,但浓度过高导致增产效果减弱。综上,叶面喷施亚硒酸钠可提高黑豆各器官总硒含量,但黑豆籽粒有机硒转化率随喷施浓度的增加呈下降趋势,且黑豆籽粒有机硒主要以蛋白质形式存在。本研究结果为应用外源硒强化技术生产富硒黑豆提供了科学依据。     

Yield and quality of fennel (Foeniculum vulgare Mill.) in relation to basal and foliar application of nitrogen and phosphorus

A split‐plot field trial was conducted to study the effect of foliar application of 0 kg/ha (control), 20 kg N/ha, 2 kg P/ha or 20 kg N + 2 kg P/ha at two basal levels, viz., 90 kg N + 40 kg P/ha (optimal dose) and 60 kg N + 27 kg P/ha (sub‐optimal dose). Each group received 50 kg K/ha, which was applied uniformly on the yield and quality of fennel. Spray was applied at the flowering stage, 120 days after sowing.

The optimal basal dose gave better results than did the sub‐optimal one. Spray of 20 kg N + 2 kg P/ha proved optimum. This spray proved more effective at sub‐optimal than at optimal basal dose. The percentage of anethole (but not of fenchone) in the essential oil was significantly higher in plants grown with the sub‐optimal basal dose. Foliar application of N, P and N + P, on the other hand, decreased the anethole content of oil and increased that of fenchone significantly. Hence, foliar feeding may be recommended if the oil is required for perfumery and confectionary industries.     

Effect of selenium on the yield and quality of green tea leaves harvested in early spring

Foliar applications of a fertilizer of selenite or selenate were carried out to determine the influence of selenium on the yield and quality of green tea leaves harvested in early spring. Numbers of sprouts and the yield were significantly increased by the application of selenium. The sweetness and aroma of green tea leaves were also significantly enhanced, and bitterness was significantly decreased by the application of selenium. However, no significant differences were found in sweetness, bitterness, and aroma between tea leaves fertilized with selenite and selenate. Se concentration was significantly increased by selenium fertilization, and tea enriched by sodium selenate had a significantly higher selenium content than did tea enriched by sodium selenite. Total amino acid and vitamin C contents were significantly enhanced by the application of selenium. Tea polyphenol contents were significantly decreased by fertilization with selenium. The marked difference of tea polyphenols was also found between applications of selenite and selenate.