田间条件下不同园龄茶树氮、磷、钾养分需求规律的研究

本文通过分析大田条件下1、2、3、5和10龄龙井43茶园头年秋天整株茶树、第二年采摘新稍、修剪物和落叶的生物量以及氮、磷、钾养分量,研究不同园龄茶树氮、磷、钾养分需求规律。1龄茶园到5龄茶园,茶树地上部生物量、氮、磷、钾养分量分别增加约32倍、21倍、25倍、29倍,到10龄茶园,与5龄茶园相比,仅分别增加约71%、17%、13%、14%。从1龄到2龄茶园,茶树氮、磷、钾的年养分需求量分别为90.01、5.71、31.11kg/hm2,从2龄到3龄茶园,茶树氮、磷、钾的年养分需求量分别为122.74、9.63、45.14kg/hm2,从3龄到4龄茶园,茶树氮、磷、钾的年养分需求量分别为144.03、10.33、47.99kg/hm2。幼龄茶树经过定型修剪后,吸收的养分有一部分通过修剪物和落叶回归土壤,因茶树生长(不包括修剪物和落叶等)并留存在茶树上的养分量占总量的43.9%、48.7%、61.3%左右。进入青年期,如5龄茶园,茶树氮、磷、钾的年养分需求量分别约为164.4、12.68、71.29kg/hm2。进入采摘后,茶树所需的养分主要用于新稍生长,一部分分配到修剪物和落叶之中,因茶树生长(不包括修剪物和落叶等)并留存在茶树上的氮、磷、钾养分量比较稳定且只占较少份额(氮、磷、钾养分量分别仅约为7.54、0.53、5.44kg/hm2)。本试验对田间条件下不同生育期的茶树氮、磷、钾养分需求量的研究建立了试验分析方法,为进一步研究茶树养分需求规律提供了一条新的思路。     

西双版纳不同森林类型凋落叶与土壤碳氮变化研究

通过对西双版纳原始林、次生林和橡胶林土壤和凋落叶碳氮含量及碳氮比值间的变化特征研究,探讨林型变化下生态系统中生物化学计量比值的分异规律。研究结果表明:样品中土壤和凋落物氮对C/N值的影响要高于碳。西双版纳土地利用类型决定了土壤和凋落叶的碳氮含量,原始林SOC含量最高,橡胶林初产期(10 a)最低,而STN含量总体上橡胶林要高于原始林和次生林,不同树龄橡胶林土壤氮含量随林龄增加和割胶的进行发生了流失。不同林型间土壤有机碳(SOC)、全氮(STN)和凋落物碳氮比(C/N)的差异性显著,而土壤碳氮比、凋落物碳氮含量与林型相关性较弱。SOC、STN含量与凋落叶碳氮含量具有一定的负相关关系,说明土壤碳氮主要来自凋落物分解后养分的循环过程。     

云南澳洲坚果园土壤和叶片养分评价

通过对云南省西双版纳、普洱、临沧、保山、德宏等5个具有地域代表性的澳洲坚果种植区中的土壤和叶片养分分析,发现澳洲坚果种植区土壤与叶片养分具有较大的地域差异。47个澳洲坚果园的土壤pH、有机质和碱解氮、有效磷、速效钾、交换性钙、交换性镁、有效硼、有效铜、有效锌平均含量分别为：4.94、29.17g/kg和109.23、36.64、200.05、352.78、85.65、0.60、2.03、2.14 mg/kg;叶片氮、磷、钾、钙、镁和硼、铜、锌平均含量分别为：16.36、0.73、8.39、6.05、0.80 g/kg和17.74、3.46、9.86 mg/kg。土壤pH值低于5.0的样品比例占60%,土壤有机质、碱解氮、有效磷、速效钾、有效铜和有效锌含量达到丰富程度的样品比例依次分别占40%、31%、47%、56%、38%和18%,土壤交换性钙、交换性镁和有效硼达到缺乏程度的样品比例依次为71%、67%和84%。叶片氮、磷、钾、钙、镁和锌养分达到适宜和丰富的样品比例为97%、67%、100%、49%、51%和100%,磷、钙、镁、硼和铜养分达到缺乏程度的样品比例依次为33%、51%、49%、87%和88%。因此,云南澳洲坚果园土壤肥力调控的重点是增施有机肥,减施磷钾肥,补施钙镁中量元素及铜硼等微量元素。     

秸秆还田条件下不同有机肥对土壤养分和冬小麦养分积累的影响

为了解秸秆还田条件下不同类型有机肥在麦田的施用效果,采用田间试验,设置T1(6 000kg·hm~(-2)玉米秸秆粉碎深翻还田)、T2(6 000kg·hm~(-2)玉米秸秆粉碎+有机肥A 1 500kg·hm~(-2)深翻还田)、T3(6 000kg·hm~(-2)玉米秸秆粉碎+有机肥B 1 500kg·hm~(-2)深翻还田)3个处理,研究了秸秆还田条件下不同类型有机肥对冬小麦越冬期、孕穗期和成熟期土壤微生物量碳(MBC)、氮(MBN)、土壤速效养分含量、冬小麦植株养分积累量以及冬小麦产量和当季经济效益的影响。结果表明,与T1处理相比,T2处理冬小麦各生育时期土壤微生物量碳、氮、土壤矿质态氮和土壤速效钾含量、植株氮和钾的积累量、冬小麦孕穗期和成熟期土壤速效磷含量、植株磷的积累量均显著提高;冬小麦实际产量和当季相对净收益亦均显著增加,分别提高了17.5%和22.0%。T3处理冬小麦越冬期土壤微生物量碳、越冬期和孕穗期土壤微生物量氮、各生育期土壤矿质态氮和越冬期土壤速效钾、各生育期植株氮和钾的积累量、孕穗期和成熟期植株磷的积累量亦均显著提高;冬小麦实际产量提高10.3%,达显著水平,但其当季经济效益并未显著提高。本试验条件下,综合施用两种有机肥对不同指标的影响,以T2处理效果更佳。     

山西省北部地区玉米化肥施用现状——基于应县大黄巍乡玉米种植户施肥状况调研

通过系统分析山西省朔州市应县玉米种植户化肥投入现状发现,农户的玉米平均产量为10.3 t/hm~2,平均施肥总量为465 kg/hm~2,氮、磷、钾肥的用量分别为262、123、84 kg/hm~2,氮、磷、钾偏生产力分别为42、69、135 kg/kg。基于土壤养分测试,该地区推荐的氮、磷、钾施肥量分别为225、90、45 kg/hm~2。与推荐施肥量相比,氮、磷、钾肥施用过量农户的比例分别为75%、81%和93%。过量的养分投入并没有显著增加玉米产量。     

控释肥用量对花生田土壤养分含量及产量品质的影响

为探究控释肥用量对花生田土壤养分含量及产量品质的影响,本试验以大花生品种"青花7号"为材料,选用金正大控释肥(N-P_2O_5-K_2O:28-6-7),设置了0、450、600、750、900kg/hm~2 5个施肥水平,在大田条件下研究了控释肥用量对花生产量、品质及耕层土壤碱解氮、速效磷、速效钾含量的影响。结果表明,花生整个生育期,土壤碱解氮、速效磷、速效钾含量均先升高后降低,且随着控释肥用量的增加呈递增趋势。花生整个生育期,土壤碱解氮、速效磷、速效钾含量均大于对照,后期差异显著。在0~750kg/hm~2用量范围内,控释肥用量与荚果产量之间呈显著正相关关系,控释肥用量为750kg/hm~2时,花生产量达到最高为8602kg/hm~2。此外,施用控释肥还可提高花生籽仁中脂肪、蛋白质、可溶性糖和O/L值,改善花生品质,在控释肥用量为750kg/hm~2时,花生品质改善效果较好。     

间作对咖啡和澳洲坚果根系形态、分布及养分累积的影响

为探明澳洲坚果与咖啡间作对地上部生长及地下部互作效应,为生产推广复合高效栽培模式提供理论依据,布置了咖啡和澳洲坚果间作盆栽实验,以二者分别单作为对照,分析植株的生长量、生物量、养分含量、根系形态以及土壤养分的差异。结果表明：（1）间作咖啡和间作澳洲坚果根干重、茎干重、单株总干重分别为40.86、50.38、148.34 g,22.38、33.19、111.97 g,间作咖啡显著大于间作澳洲坚果,叶干重二者差异不显著;幼龄期间作条件下,咖啡生长速率快于澳洲坚果。间作咖啡、间作澳洲坚果与各自单作根、茎、叶、单株干物质累积量差异均不显著。（2）间作澳洲坚果叶氮累积量2135.27 mg显著大于间作咖啡的1957.60 mg,除此之外,间作咖啡根氮、磷、钾,茎氮、磷、钾,叶磷、钾,单株总氮、磷、钾累积量均显著大于间作澳洲坚果,表明幼龄期间作条件下,咖啡养分累积量占优势;间作澳洲坚果根氮、钾累积量742.80、103.22 mg显著大于单作的535.00、37.77 mg,可见,间作根系竞争促进澳洲坚果增加根部氮的分配,提高根钾的吸收累积。（3）间作咖啡和间作澳洲坚果根长、根表面积、根体积在本株侧面根系生态位分布量占总取样量的62.63%~65.67%,其次是在株间根系生态位分布量占总取样量的16.01%~27.53%,在对应本株近侧和对应本株远侧面2个根系生态位分布较少,可见间作后二者根系主要分布于自身根系生态位,在株间位置根系交叉重叠,未在土壤深度和广度空间形成差异分布,属于间作竞争型根系统。咖啡与澳洲坚果均属于浅根系,侧根直径小,成龄澳洲坚果是高大乔木,随着时间的推移,与咖啡间作将处于地上、地下部竞争优势。     

我国水稻土壤有效磷和速效钾丰缺指标与适宜磷钾施用量研究

系统总结了我国开展的水稻土壤有效磷和速效钾丰缺指标与适宜养分施用量研究。结果表明,近30年来我国水稻土壤有效磷丰缺指标出现了明显上升趋势,速效钾丰缺指标出现了下降趋势;土壤有效磷和速效钾丰缺指标不同区域之间差异较大,以缺素处理相对产量90%指标为例,土壤Olsen-P和NH4OAc-K含量变幅为2.5~46mg/kg和21~202 mg/kg;除辽宁、福建、广东和云南等省外,我国水稻土壤有效磷和速效钾丰缺指标研究尚存在很多空白区域;水稻土壤缺磷缺钾较为普遍,第2~4级为土壤有效磷和速效钾集中分布的丰缺级别,缺素处理相对产量大多处在70%~100%;土壤养分丰缺指标研究的试验点数不宜过少,丰缺指标高端和低端采用外推数据需谨慎,并应予以注明;适宜养分施用量与土壤养分丰缺级别呈线性负相关,与水稻目标产量呈线性正相关,与养分当季利用率呈线性负相关;当磷素当季利用率20%、目标产量4.5~15.0 t/hm~2时,土壤有效磷丰缺级别第1~7级的水稻适宜施磷量范围依次为0、20~68、41~135、61~203、81~270、101~338和122~405 kg/hm~2;当钾素当季利用率50%、目标产量4.5~15.0 t/hm~2时,土壤速效钾丰缺级别第1~7级的水稻适宜施钾量范围依次为0、22~72、43~144、65~216、86~288、108~360和130~432 kg/hm~2。     

秸秆还田量对免耕黑土速效养分和玉米产量的影响

研究了不同秸秆还田量对免耕黑土速效养分含量和玉米产量的影响.结果表明:秸秆还田可以增加土壤表层(0～10 cm)碱解氮、速效磷和速效钾含量,以5000 kg/hm~2秸秆还田处理效果最为明显.研究同时发现,玉米产量与碱解氮含量呈显著的相关性(P<0.05).     

花垣植烟土壤养分含量及丰缺状况分析

为探明花垣县植烟土壤养分状况,2015年在花垣县共采集160个土壤样本,对其养分状况进行综合分析。结果表明:花垣县植烟土壤p H值平均为5.45,碱解氮163.78 mg/kg,有效磷38.64 mg/kg,速效钾244.07 mg/kg,全氮2.36 g/kg,全磷0.80 g/kg,全钾22.90 g/kg,有机质32.58 g/kg。花垣烟区土壤养分含量总体上较丰富,土壤有机质、氮素和磷素含量偏高,少数乡镇速效钾含量偏低,一半以上的乡镇植烟土壤为酸性和极酸性。不同植烟乡镇土壤养分特征有明显差异,如补抽土壤的碱解氮含量较高,有效磷和速效钾含量则较低;排碧土壤的碱解氮含量较高,有效磷和速效钾含量极高;道二土壤的碱解氮和速效钾含量适宜,有效磷含量偏高。针对花垣烟区植烟土壤养分丰缺状况,应当合理控制氮和磷的施肥量,采用有机无机肥配施的办法提高钾肥利用率,并适当调节烟区土壤p H值。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.     

La pourriture fongique des tubercules de pomme de terre en atmosphère contrôlée

Résumé Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.

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Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.

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Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.

     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Marine Pharmacology in 2016–2017: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems,and Other Miscellaneous Mechanisms of Action

The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.     

Effects of Micronutrient Deficiencies on Human Health: Its Status in South Asia

SUMMARY

Vitamin A, iodine, and iron deficiencies affect large numbers of people worldwide. A deficiency of one or more of these micronutrients adversely affects the physical and mental abilities of humans. South Asia contains a high percentage of these individuals, not just because of its large population, but also the prevalence of deficiency is higher there than in many other parts of the world. The reasons for the high rates of deficiency in South Asia are many, but they include inadequate availability of micronutrient-rich foods, sub-optimal dietary habits, and high rates of infection. Across the region, national plans vary from (a) increasing availability of appropriate foods, (b) introducing new dietary behaviors, (c) improving health status, and (d) directly addressing deficiency through intervention programs. The extent to which each of the countries is making progress toward the goals of these plans can help in understanding the priorities for future efforts to address micronutrient malnutrition. This article discusses the adverse effects of micronutrient deficiencies in humans with special reference to South Asia.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.