烟叶背靠式分风板散叶密集烘烤技术研究

研究了背靠式分风板散叶密集烘烤技术在烤烟上的应用效果,结果表明：应用背靠式分风板散叶密集烘烤技术,可增加密集烤房装烟容量61.51%,每千克干烟叶减少烘烤成本0.62元,单炉经济效益增加8 559.06元;烤后烟叶上等烟比例、均价、单叶重、产值均高于对照,烟叶感官评吸质量有所提高。     

移栽期对烤烟农艺性状及经济性状与上部烟叶可用性的影响

在凤凰县千工坪烟区,以K 326为试验材料,研究了移栽期对烤烟病害程度、农艺性状、经济性状及上部烟叶可用性的影响,结果表明:适当推迟移栽烤烟,可显著降低上部烟叶赤星病与病毒病危害,减少上部烟叶的病斑,增加烟株株高、有效留叶数、烟叶长度与宽度,提高烟叶产量。与4月22日移栽相比,5月11日移栽的烟叶产量、产值、均价及上等烟比例分别增加489 kg/hm2,9 702元/hm2,1.4元/kg和16.7%。在湘西凤凰县或气象条件类似的植烟区,适当推迟烤烟移栽,可显著降低上部烟叶的比例,上部烟叶开片情况显著改善,提高了上部烟叶的可用性,并显著增加了产值与上等烟比例。     

氨基寡糖素和钾营养调节剂对烟草普通花叶病毒病的防治效果

为探索防治烟草普通花叶病的农艺措施,采用田间试验,研究了氨基寡糖素和钾营养调节剂配施防治烟草普通花叶病毒病的效果及对烟叶产量、质量的影响。结果表明,氨基寡糖素和钾营养调节剂配合施用能有效降低烟株普通花叶病毒病的发病率和病情指数,平均防效达到56.31%,两者配施还明显提高了烟叶的产量、产值、均价、上等烟比例等经济指标,分别较对照(喷施清水)提高27.60%、44.26%、13.02%、42.48%,并能提高烟叶的外观质量和评吸质量。     

烟叶外观质量与化学成分及评吸质量的相关性探析

[目的]研究烟叶外观等级质量与烟叶内在品质间的关系,为烟叶分级提供一个量化的指标。[方法]以K326为材料,研究初烤烟叶的外观质量和经济性状、常规化学成分及感官评吸质量的关系。[结果]结果表明,烟叶外观质量好的烟叶在经济性状上表现为中上等烟叶比例、均价高;烟叶外观质量与常规化学成分含量之间呈负相关关系,与烟叶的感官评吸质量呈正相关关系。[结论]研究结果为烟叶生产提供了借鉴。     

高海拔地区移栽期对烤烟生长及产量的影响

2010年在湖南龙山县研究了高海拔地区移栽期对烤烟生长及产量、产值的影响。结果表明：烤烟在5月10左右移栽,烟株产量、上等烟比例、均价及产值较高,而发病率较低。推迟或提前移栽,烟叶的发病率上升,产量、上等烟比例、均价及产值均下降。     

小麦秸秆覆盖量对烤烟生长及烟叶产质量的影响

采用田间小区试验,研究了不同小麦秸秆覆盖量对地烟和田烟农艺性状及烟叶产质量的影响。结果表明:秸秆覆盖对前期烟株生长作用不大,到后期覆盖量为500 kg/(667 m2)处理的烟株农艺性状显著优于其他处理,烟叶化学成分协调性较好、经济性状较佳,可提高上部烟叶总糖、还原糖的含量,降低中、上部烟叶氯的含量,提高中、上部烟叶的钾/氯比值,使中、上部烟叶的糖/碱比值较接近10,下部烟叶的氮/碱比值较接近1;地烟和田烟的烟叶产量、产值、均价、上等烟率和中上等烟率分别比无覆盖的对照高16.39%、31.81%、13.29%、37.72%、12.69%和15.75%、34.11%、15.88%、12.18%、8.80%。覆盖量为750 kg/(667 m2)的处理促进了下部烟烟叶品质的提高,使下部烟叶糖/碱比值较接近10。综合来看,覆盖量为500 kg/(667m2)的处理促进烟株生长、提高烟叶产质量的效果更明显。     

四个烤烟新品种的产量性状与抗病性比较

为筛选出普洱地区适宜性较强的烤烟品种,发展特色优质烟叶,2009年于普洱市景东县烤烟产区比较了KRK 26,KRK 22,KRK 23,T 27四个烤烟新品种的生育期、农艺性状、经济性状(产量、产值和上等烟比例)、抗逆性和烟叶品质的差异性。结果显示:KRK 26大田生育期最短,具有较强的耐肥性和耐熟性,烟叶外观质量较好,产量可达1 772.50 kg/hm2,产值可达25 808.18元/hm2,上等烟比例可达52.46%,均表现最好。各参试品种均对黑胫病、青枯病、角斑病、根结线虫病、CM V、PVY表现出抗性,除此之外,KRK 26还对TM V表现出抗性。因此,KRK 26在当地具有较强的推广潜力。     

散叶烘烤和挂杆烘烤的烟叶质量和经济效益分析

为探索烤烟生产减工降本、提质增效的技术措施,研究了散叶烘烤和挂杆烘烤对烟叶质量和产量的影响,并对其经济效益进行了综合分析。结果表明：（1）每50 kg鲜烟叶散叶烘烤可产生干烟10.14 kg,较挂杆烘烤增加1.70 kg,散叶烘烤的不列级干烟较挂杆烘烤减少0.81 kg,产值增加59.34元,均价提高3.02元／kg;上等烟率、桔黄烟率分别提高13.60％、9.60％。（2）散叶烘烤较挂杆烘烤产值增加3628.61元／炕,但降低能耗的效果不显著。     

不同植烟土壤改良模式对烤烟产质量的影响

为探索湘西州烟区植烟土壤改良方法,研究了玉米秸秆、绿肥、玉米秸秆与绿肥结合还田对烤烟产质量的影响。结果表明:玉米秸秆、绿肥、玉米秸秆与绿肥结合还田均能提高烟叶上等烟比例、产量和产值,提高烟叶开片率、平衡含水率和钾含量,以玉米秸秆与绿肥结合模式的土壤改良效果最好。     

延迟采收时间对稻茬烤烟上部烟叶产质量的影响

为明确浙江中烟主导的稻茬烤烟上部烟叶适宜采收成熟度,采用云烟87,在湖南江华烟区开展上部烟叶延迟采收试验.结果表明:随上部烟叶采收延迟,鲜烟叶的SPAD值下降;烤后烟叶的单叶重、叶质重降低,总糖、还原糖、氯含量下降,烟碱、总氮、钾含量增加;烟叶的上等烟比例、均价、产量和产值降低.湖南江华烟区上部烟叶适宜采收成熟度要求叶...     

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.     

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.     

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.     

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.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.