施肥对蔬菜硝酸盐积累的影响

就施肥对蔬菜硝酸盐积累的研究状况和展望进行了综述。内容包括施用氮肥，配方施肥，施用微肥对蔬菜硝酸盐积累的影响。针对控制蔬菜硝酸盐含量，提高产量的途径及今后研究的方向提出了建议。     

施肥对蔬菜中硝酸盐含量的影响

蔬菜极易累积硝酸盐，美国学者White曾指出，人体摄人的硝酸盐81．2％来自蔬菜。蔬菜硝酸盐的积累，一方面与蔬菜种类、品种、器官组织等作物品种特性有关，另一方面与施肥、光照、土壤水分等环境条件密切相关，其中施肥是影响蔬菜硝酸盐积累的主要因素。为了研究不同肥料配比、不同氮肥用量以及施用生物肥、叶面肥对蔬菜中硝酸盐含量的影响，我们进行了本试验。     

蔬菜硝酸盐积累机制研究的现状与展望

概述了蔬菜积累硝酸盐的机制及影响因素，并就今后蔬菜积累硝酸盐的调控及研究方向问题提出了建议。     

菠菜不同品种硝酸盐含量的分析

近年来，国内外学者对蔬菜体内硝酸盐含量进行了大量研究，结果表明：不同种类的蔬菜硝酸盐含量存在差异，一般叶菜类(如菠菜、芹菜)硝酸盐含量较高(1000-2500mg／kg或以上)。但同时也应注意到，同种蔬菜不同品种间硝酸盐积累也存在较大差异。造成蔬菜种类间、品种间硝酸盐积累差异的     

蔬菜中硝酸盐积累的遗传特性

蔬菜中硝酸盐的过量积累给人类的健康带来了危害。本文探讨了不同蔬菜中硝酸盐积累的差异性以及蔬菜中硝酸盐积累的遗传行为规律,为降低蔬菜中硝酸盐含量的育种工作提供参考。     

科学施肥控制蔬菜硝酸盐

近年来 ,由于蔬菜栽培施用化学氮肥偏多 ,蔬菜可食部分硝酸盐的累积问题已为人们所关注。蔬菜易于富集硝酸盐 ,人体摄入的硝酸盐有81 .2 %来自蔬菜。目前我国蔬菜 (尤其是叶菜 )中硝酸盐含量超标现象突出。食用高硝酸盐蔬菜 ,易患高铁血红蛋白变性症 ,会感到缺氧 ,甚至危及生命 ;另一方面 ,硝酸盐在动物体内易还原为亚硝酸盐 ,进而与仲胺结合 ,成为一种致癌物质 ,是人体胃肠道癌变的原因之一。因此 ,在生产上应严格控制蔬菜硝酸盐含量 ,以保证人体健康。科学施肥是减少蔬菜硝酸盐积累的最有效措施。1　硝酸盐积累的原理　　旱作蔬菜对氮素的…     

防治蔬菜中污染物残留的技术途径

蔬菜污染物的积累受到环境(水、土、气)质量状况的影响,也受到人为农业技术措施的影响。因此,控制蔬菜中污染物的残留是一项综合性的措施。当前,对蔬菜污染影响的主要污染物是重金属、农药、硝酸盐和氟化物等。除硝酸盐外,国家颁布     

如何在蔬菜施肥技术中控制硝酸盐含量

<正>蔬菜是人们日常生活中不可缺少的重要副食品,能为人们提供各种维生素、矿物质,但又容易富集对人体有害的硝酸盐。减少蔬菜中的硝酸盐积累,施肥技术是关键,其中包括合理的肥料品     

不同施肥方式对蔬菜硝酸盐含量的影响

蔬菜是一类极易富集硝酸盐的食品,研究证明,随食品摄入人体的硝酸盐中有80%以上来自蔬菜。蔬菜硝酸盐积累的影响因素很多,施肥是非常重要的因素之一。因此通过合理施肥,减少硝酸盐在蔬菜体内的积累,是当前蔬菜生产中急待解决的问题。     

蔬菜硝酸盐积累的控制措施

1硝酸盐对人体的危害硝酸盐对人体的危害早已受到人们的普遍关注。研究证明,硝酸盐在人体内经微生物作用可被还原成有毒的亚硝酸盐,它可与人体血红蛋白反应,使之失去携氧功能,造成高铁血红蛋白症,长期摄入亚硝酸盐会造成智力迟钝。据报道,亚硝酸盐还可间接与次级胺结合形成强致癌物质亚硝胺,进而诱导消化系统癌变,如胃癌和肝癌。人体摄入的硝酸盐有81.2%来自蔬菜。因此,控制蔬菜中硝酸盐含量的过多积累,是减少对人体危害的一个重要途径。2降低硝酸盐积累的措施2.1大量使用有机肥有机肥料是一项降低蔬菜硝酸盐的有益的农业措施,它具有保持地…     

不同有机肥种类对生菜硝酸盐含量的影响

在露地和大棚条件下研究了5种不同有机肥对生菜硝酸盐积累的影响,结果表明:无论露地和大棚,不同有机肥对生菜单球质量和硝酸盐积累的影响都达极显著水平,施用牛粪和生物发酵鸡粪种植的生菜硝酸盐含量较低,豆粕、猪粪则使生菜硝酸盐含量显著升高。同一种有机肥前处理方法不同,对生菜硝酸盐含量的影响也不同,生物发酵鸡粪的处理硝酸盐含量低于膨化消毒鸡粪的处理。露地和大棚试验中均以处理1(牛粪)最好,能显著提高生菜单球质量和降低生菜硝酸盐含量。     

双氰胺对无土栽培菜薹硝酸盐积累的影响

 研究了双氰胺对甘蔗渣基质培菜薹硝酸盐积累的影响。结果显示, 采收前20 d施用双氰胺的处理, 其基质中的NO ₃^-_-N含量比不施双氰胺处理的低, 而NH₄⁺-N含量较高; 双氰胺显著降低菜心硝酸盐含量, 而对产量无明显影响。     

Nitrogen accumulation and nitrate reductase activity in MM. 106 apple trees as affected by nitrate supply

The effect of nitrate supply in the nutrient solution on N accumulation was investigated in various organs of MM.106 apple trees (Malus domestica Borkh.). Increasing nitrate supply increased the concentration and amount of total N in leaves and stems, but there was a saturation point of total N accumulation in response to the nitrate supply. The increased accumulation of total N in leaves and stems with increasing nitrate supply were due to increases in reduced N, since nitrate N remained relatively constant. Reduced N contents of trunk bark and trunk wood were significantly decreased when low nitrate was supplied, whereas that of roots was changed insignificantly. Most organs contained only a small portion of their total N as nitrate. The activities of nitrate reductase (NR) were measured using an in vivo assay either with or without nitrate for estimating reduced N accumulation. The in vivo —N03^- NR assay may be a better way to estimate the accumulation of reduced N than the in vivo +N03^- NR assay since the in vivo +N03^- nitrate reductase activity (NRA) was not related to the changes in the reduced N concentration with the differential nitrate supplies. Increasing nitrate supply significant increased in vivo —N03^- NRA of all organs. The rate of increase of the in vivo —N03^- leaf NRA was greater than those of stems and roots with increasing nitrate supply. Consequently, the proportion of leaf NRA to the total activity increased as the nitrate supply increased. The roots exhibited higher NRA than leaves and stems. The stem also contributed considerably to the total NRA. It can therefore be concluded that the reduction of nitrate can occur in various organs of MM. 106 apple trees as long as nitrate is available.     

白菜不同品种对硝酸盐吸收积累差异原因初探

 用两组积累硝酸盐不同的白菜品种作试材，测定其吸收硝酸盐的速率、动力学常数Km与V一、硝酸还原代谢库内硝酸根浓度(MPS)和硝酸还原酶活性(NRA)，结果表明，不同白菜品种吸收硝酸根的速率、Km与V 、MPS、NRA存在较大的差异；硝酸盐积累的差异主要是由于吸收硝酸根的速率不同，与硝酸根在其体内的运转、代谢并无显著直接相关。     

Studies on the accumulation of nitrate in tomato fruit for canning

This study was carried out to investigate the factors concerning the accumulation of nitrate in tomato fruit and to find the preventive measures against heavy tin-dissolving in canned tomato juice caused by nitrate.The factors determining the accumulation of nitrate in the plant were as follows: the levels of nitrate, potassium, and calcium in the soil, the application of plant growth regulators, the tomato cultivar, and the light intensity. For obtaining fruits containing less than 3 ppm of nitrate-nitrogen, low nitrate cultivars should be grown in a sunny place on weak acid soil with split application of slow-acting nitrogen fertilizer, and a high calcium level. By proper treatment with plant growth regulators, nitrate-nitrogen content in the fruit can be decreased still more. It is also important that any particular growing-conditions in every tomato-growing district should be taken in consideration in the cultivation management for preventing the accumulation of nitrate-nitrogen.     

钼锌与不同肥料配施对大白菜硝酸盐积累及品质的影响

采用小区试验方法,研究了钼锌与不同肥料配施对大白菜硝酸盐积累及品质的影响。结果表明:添加了钼肥能明显降低大白菜中硝酸盐的含量,单施钼肥对降低硝酸盐的积累最有利;钼锌与不同肥料配施还可以促进白菜生长发育、改善品质及提高产量;钼锌与复合生物肥配施对VC、铁、蛋白质、可溶性糖及叶绿素含量的提高显著;在大白菜种植中最好是施用复合生物肥并根外追施钼锌等微肥。     

Differential utilization of nitrates by solanaceous species,crops (tomato and pepper) and weeds (black nightshade and thorn apple)

Summary

The capacity of nitrate absorption, accumulation and reduction was studied in four species of the Solanaceae. Two were cultivated species, tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.), and two weed species, black nightshade (Solanum nigrum L.) and thorn apple (Datura ferox L.), which often infest these crops. Black nightshade and thorn apple absorbed nitrates most rapidly. Maximum nitrate accumulation was observed earlier in tomato than in the other species, and as in pepper coincided with the flower bud stage. Maximum nitrate accumulation in black nightshade and thorn apple took place during flowering. Only in tomato and thorn apple did maximum nitrate reductase activity occur at the time of maximum nitrate accumulation. Growth and soil nitrate absorption was slowest in pepper, but nitrate accumulation by the plant and nitrate reductase activity was more sustained than in the other species. It was concluded that if these weeds emerge simultaneously with the crops, competition for nitrates by thorn apple, and especially black nightshade, would be greater than for the tomato crop and even more so for the pepper crop.     

氮素营养对菜薹生长和硝酸盐累积的影响

在水培试验条件下,研究了15个菜薹品种的氮素营养条件和硝酸盐积累的差异。结果表明,12个菜薹品种适宜在纯硝态氮源或硝态氮配合少量铵态氮的氮源条件下生长;有14个品种在纯硝态氮源或硝态氮配合少量铵态氮源条件下植株硝酸盐含量最高;在适宜氮源条件下,品种间生长量和硝酸盐含量以及氮素利用效率有显著差异。     

氮肥用量与黄瓜产量和硝酸盐积累的关系

氮肥达到一定施肥量后，黄瓜产量并不随施肥量的增加再增加，而果实中硝酸盐含量随施肥量增加几乎成正比例增加，高氮处理为低氮处理的２５６．４％，氮肥的合理使用应引起人们的注意；最大叶叶面积和叶片数的增长速度、叶绿素含量、净光合速率都以中氮处理为高，这是造成中氮处理产量高的物质基础     

外源水杨酸对韭菜硝酸盐累积及还原同化的影响

 针对韭菜生产中硝酸盐累积问题，研究了叶面喷施水杨酸(SA)对韭菜硝酸盐累积及还原同化的影响。在不同氮素水平下，叶面喷施3.0 mmol·L^-1SA后6～9 d可明显降低韭菜叶片硝酸盐含量15.9％～21.6％，而当SA水平达到10.0 mmol·L^-1时会加重硝酸盐的积累。叶面喷施3.0 mmol·L^-1SA后9 d，韭菜叶片硝酸还原酶(NR)和谷胺酰氨合成酶(GS)活性分别比对照增加了48.9%和40.3％、净光合速率(Pn)和可溶性蛋白含量分别提高了43.4%和21.3％；同时，韭菜叶片谷氨酸草酰乙酸转氨酶(GOT)活性和谷氨酸丙酮酸转氨酶(GPT)活性也均有增加。因此，叶面喷施的外源水杨酸显著提高了氮还原动力泵NR活性以及氮同化动力泵GS活性，同时调动光合作用和转氨作用的积极协同配合，促进了硝态氮转化为游离氨基酸和可溶性蛋白，减少了硝酸盐进入液泡贮积。