咖啡光合速率生理生态的研究

（１）不同荫蔽度下，大田咖啡叶片的各生理参数值具明显差异：光合速率、蒸腾速率、气孔密度和干湿重比都比无荫蔽的为最大，９５％荫蔽度的最小，４０％荫蔽度的居中；气孔张开率和水势则以无荫蔽的为最小，９５％荫蔽度的最大，４０％荫蔽度居中。（２）无荫蔽和４０％荫蔽地咖啡光合速率的日变化呈不对称的双峰曲线，１４：００强光下出现“午休”，而９５％荫蔽地咖啡的光合速率日变化呈单峰曲线，没有“午休”现象，峰顶位于１     

不同玉米自交系光合特性的研究

通过对20个玉米自交系单叶光合速率的研究表明：(1)玉米自交系间单叶光合速率存在极显著的差异。(2)玉米自交系的光合速率随生育时期的推延而呈单峰曲线变化，以抽雄吐丝期为最大。自交系间的差异则随着生育时期的推延而逐渐增大。(3)在生态条件差异较大的海南和北京，不同自交系光合速率值高低的稳定性变差。(4)聚光分析的结果表明，自交系在光合性能两个主要性状—净光合速率和叶面积方面表现出多种类型。     

花生群体光合速率发展动态和日变化

花生叶面积系数（ＬＡＩ）、群体净光合速率和群体呼吸速率分别在播后８２、９０和９０９５天达到高峰。ＬＡＩ与群体净光合速率的关系可分为播后８２天前的相关和其后的非相关阶段。ＬＡＩ与群体呼吸速率在播后５０天前同步增长；５０—８２天ＬＡＩ增加快，群体呼吸速率增加慢；８２９０天ＬＡＩ逐渐下降．群体呼吸速率迅速增加；９８天后同步下降四个阶段。群体净光合速率与群体呼吸速率的关系可分为播后５０天期间同步增长；５０—８０天关系不明显和９８天后同步下降的三个阶段。在不同生育时期，群体呼吸速率一天中均呈单峰曲线变化。群体净光合速率因品种而异，在苗期，海花１号一天中呈双峰曲线变化，并有严重午休现象，鲁花１１号则呈偏峰型。播种３０天后，两品种的群体净光合速率一天中均呈单峰曲线变化，１２∶００时达到高峰，早上６∶００７∶００时前、晚１７∶３０－１９∶００时后为负值。     

鼓粒期芸豆净光合速率日变化研究

运用CB-1102型光合蒸腾作用测定系统,研究了芸豆鼓粒期的净光合速率（Pn）日变化。结果表明：芸豆叶片净光合速率（Pn）日变化呈单峰型曲线,无光合午睡现象。上午10：00光合速率最大;11：00蒸腾速率最快;气孔导度的变化趋势与光合速率一致,10：00出现最大值;胞间CO2浓度呈现“早晚高,中间低”的变化规律。     

灌水量与夏玉米光合性能及产量的关系

利用大型防雨设施池栽,研究灌水量与夏玉米光合性能及产量的关系。结果表明,灌水量与夏玉米光合性能及产量呈高度正相关,不同灌水量对群体光合速率、单叶光合速率、光合速率日变化、叶面积发展动态、干物质积累量及干物质生产率产生显著差异,并随生育进展而加剧。根据产量与耗水量的关系,夏玉米13 500 kg/hm²产量水平的耗水量在630 mm左右,9 000 kg/hm²产量水平的耗水量在490 mm左右,200 mm左右为夏玉米经济产量形成的耗水临界值。穗期、花粒期土壤水分状况不同是导致产量及光合性能差异增大的重要原因之一,保证夏玉米中、后期水分适宜是提高光合性能及产量的重要条件之一。     

复合群体中玉米光合特性日变化研究

通过对小麦/玉米复合群体中玉米的光合速率、光合有效辐射、蒸腾系数、水分利用率、相对湿度、叶室温度、叶片温度和二氧化碳浓度等生态生理指标在一日内的变化进行测定、分析。结果表明:Pn、PAR、Ct、Lt和Tr的日变化均“为单峰型”曲线,其变化趋势一致。CO2浓度和RH%的日变化不明显,Sr的日变化也“为单峰型”曲线,但与Pn的相反。相关分析表明,光合速率(Pn)与PAR呈极显著正相关,与Tr的相关性达显著水平,Pn与Sr呈显著负相关,PAR与Ct、Lt、Tr呈显著相关。在水肥满足的条件下,影响群体Pn的主要生态因子是PAR,要提高复合群体中玉米的经济产量主要靠调整群体结构来完成,即选择株型紧凑的玉米品种不仅能保证光合面积,而且还可改善群体内部的光照条件,从而提高群体的光合能力和经济产量。     

苦碟子光合作用日变化及其与环境因子关系的研究

本文对苦碟子叶片净光合速率日变化及其与环境因子的相互关系进行了研究,为苦碟子栽培提供参考。结果表明：苦碟子净光合速率日变化呈明显的双峰曲线,峰值出现在上午10时和下午14时,分别为16．82,14．33μmol／m2／s,有轻微的光合“午休”现象。经相关性分析,净光合速率与光合有效辐射、蒸腾速率、气孔导度之间呈正相关,与胞间CO2浓度呈负相关,与空气相对湿度的相关性不显著。     

盘锦地区稻米品质与灌浆期光合速率相关性研究

以2010年辽宁省盐碱地研究所试验点省区试中晚熟组部分水稻品种为试材,测定稻米品质及水稻群体光合速率,结果表明：水稻品种间稻米品质及群体光合速率均存在差异,齐穗后14 d左右时水稻群体光合速率与稻米的垩白粒率、垩白度呈显著或极显著正相关。     

高产冬小麦不同分蘖成穗类型品种群体光合能力的研究

用Ｌｉ－６２００光合测定仪对高产冬小麦两种不同分蘖成类型穗类型的６个品种群体光合速率进行了测定,结果表明,两类型小麦群体光速速率变化基本 全生育期内各体光速速率变化呈单峰型曲线,至挑旗达最大值。小麦生长前、中期群体大小是决定光合能力的关键因素,开花期以后群体大小的影响逐渐变小,灌浆后期落黄好的品种群体光速率高,反之则较低,小麦各体光合速率与叶面积系数、地上部干物质积累量和籽粒产量呈正相关。证明建立     

夏大豆群体光合特性的研究

本文研究了夏大豆的群体光合特性。结果表明，夏大豆群体内光强自上而下逐渐减弱，群体光合随光减弱而明显下降。开花结荚期一天中，１３时群体光合速率达最大值。在一定范围内，密度大的光合速率在上午上升得快，峰值持续的时间长，对早，晚的弱光利用率较高。音以前和１９时以后，各群体的光合速率均为负值。分枝期的群体光合速率主要决定于种植密度。开花结荚期的群体光合速率与种植密度呈抛物线关系，与百粒重，生物产量和籽粒产     

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.