高有机质土壤条件下施氮对强筋小麦产量及品质的影响

为研究高有机质含量土壤条件下施用氮肥对强筋小麦产量及品质的影响，选择土壤有机质含量为3．09％的地块，通过播前底施和拔节期追施等量氮肥（225kg／ha），对两个强筋小麦品种（8901-11和济麦20）的产量和部分生理及品质指标进行了研究。结果表明，增施氮肥有利于提高叶片叶绿素含量、氮素含量以及旗叶硝酸还原酶活性；施用氮肥可显著提高籽粒产量、籽粒蛋白质含量、蛋白质产量、沉淀值、谷蛋白大聚合体及谷蛋白含量，且追施效果优于底施；追施氮肥可以更好地调节籽粒蛋白的组成及含量，从而改善籽粒营养及加工品质。对于清蛋白、球蛋白和醇溶蛋白等三种蛋白质组分的含量，不同小麦品种的施氮反应不尽相同。本试验中，施氮处理对8901-11的影响大于对济麦20的影响。     

氮肥施用量对超高产玉米光合性能及产量的影响

在田间栽培条件下,研究不同施氮量对玉米植株光合性能及产量的影响。结果表明,增施氮肥能够增加玉米叶片的叶绿素含量、叶面积指数,提高光合速率、蒸腾速率和气孔导度。施用过量的氮肥会造成植株贪青徒长,使生育后期的光合速率、蒸腾速率和气孔导度下降,影响产量。施氮量300 kg/hm2为试验区最适施氮量。     

施氮对花后遮光条件下小麦产量与蛋白质含量的影响

为探讨施氮对花后弱光逆境下小麦籽粒产量和蛋白质含量的影响,选用2个对弱光敏感性不同的小麦品种（济麦22和济核916）,设置3个施氮水平（0、120和240 kg·hm^-2）,在花后遮去60%的自然光条件下研究了施氮量对小麦籽粒产量与蛋白质含量的调控效应。结果表明,增施氮肥可延缓花后遮光条件下两个小麦品种旗叶叶绿素下降,使PSⅡ实际光化学效率和净光合速率维持较高水平,促进旗叶可溶性糖含量合成,提高籽粒灌浆速率,增加穗数、穗粒数和籽粒产量。增施氮肥提高了遮光条件下两个小麦品种旗叶硝酸还原酶活性、籽粒谷氨酰胺合成酶活性和籽粒游离氨基酸含量,增加籽粒蛋白质含量。济麦22的籽粒产量以240 kg·hm^-2施氮处理最高,籽粒蛋白质含量在120 kg·hm^-2和240 kg·hm^-2施氮处理间无显著差异;济核916的籽粒产量和蛋白质含量均以120 kg·hm^-2施氮处理最高。由此可见,在花后遮光条件下适量施氮可提高小麦光合能力和促进碳氮代谢,最终增加籽粒产量和蛋白质含量。     

施氮和大气CO2浓度升高对春小麦拔节期光合作用的影响

为明确高大气CO2浓度下小麦叶片光合作用的适应机制及氮素的调控作用,利用开顶式气室,通过盆栽试验,测定和分析了不同大气CO2浓度和施氮量下小麦拔节期叶片的光合参数、叶绿素含量等指标.结果表明,高大气CO2浓度(760 μmol·mol-1)处理的小麦叶片的叶绿素含量、光合速率(Pn)、气孔导度(G5)和蒸腾速率(Tr)均随着施氮水平的升高而升高,平均增幅分别为31.6%、69.6%和57.6%,而胞间CO2浓度(Ci)和水分利用效率(WUE)随施氮水平的升高而呈先下降后上升的趋势.高大气CO2浓度下小麦叶片Pn、Ci和WUE显著高于正常CO2浓度(400 μmol·mol-1)处理,平均增幅分别为36.8%、74.O%和102.7%.在400 μmol·mol-1 CO2浓度下测定时,与正常大气CO2浓度下生长的小麦相比,高大气CO2浓度下生长的小麦拔节期叶片Pn在高施氮水平(0.2 g N·kg-1土)下未发生下调,而在低、中施氮水平(0和0.1 g N·kg-1土)下叶片Pn明显降低.因此,高大气CO2浓度下施氮可显著提高小麦叶片的Pn和WUE,且充分供氮可使叶片不发生光合适应现象,这可能与较高的施氮水平提高了高大气CO2浓度下小麦叶片的叶绿素含量有关.     

施氮对灌浆期冬小麦不同叶片SPAD值及光合速率的影响

为了解不同施氮水平下小麦叶片叶绿素含量和光舍速率的变化，以冬小麦小偃22为供试材料进行小区试验，测定和分析了施氮后冬小麦灌浆期不同叶片的SPAD值及光舍速率。结果表明，在同一施氮水平下，小麦植株不同叶片SPAD值及光舍速率均为：旗叶〉倒二叶〉倒三叶〉倒四叶，说明小麦叶片叶绿素含量及光舍速率在植株上的分布特征相对固定，受施氮水平的影响较小。在施氮量小于90kg／ha时，小麦各叶片SPAD值随施氮水平的增加而增大；当施氮量超过90kg／ha时，小麦各叶片SPAD值变化趋势不明显。随施氮水平的提高，小麦叶片的光合速率呈现出先增加后下降的趋势，施氮量为135kg／ha时光合速率最高。     

高产小麦花后植株氮素累积、转运和产量的水氮调控效应

为给高产小麦合理灌溉和氮肥施用提供科学依据,以小麦品种豫麦49-198为材料,在豫北高产麦田研究了不同水、氮处理对小麦花后植株氮素吸收、累积和转运的影响。试验采取灌水与施氮量两因子裂区设计,其中灌水为主区,设全生育期不灌水(W0)、拔节期灌1水(W1)和拔节水+开花水灌2水(W2)3个水平;施氮量为副区,设置4个水平,即每公顷施纯氮量0kg(N0)、180kg(N1)、240kg(N2)和300kg(N3)。结果表明,W1和W2下小麦籽粒产量较W0分别提高16.6%和25.6%,蛋白质产量分别提高14.2%和19.2%。籽粒产量和蛋白质产量的提高与氮素积累和转运有关。灌水增加了茎鞘、叶片和颖轴的氮素累积量,提高了茎鞘氮素转运效率和贡献率,但减小了叶片氮素转运量、转运效率和贡献率。施氮可显著增加小麦花后植株氮素累积量及氮素转运量,进而提高小麦籽粒氮素累积量和蛋白质产量。与N0相比,成熟期N1、N2和N3籽粒氮素累积量分别增加44.9%、59.3%和60.2%,叶片贡献率分别增加60.2%、40.9%和61.5%,籽粒产量分别提高75.3%、73.5%和79.8%。水氮互作显著影响叶片氮素累积量和氮素转运效率,但对籽粒产量和蛋白质产量影响不显著。综合来看,在豫北高产条件下,不灌水或灌1水时小麦适宜施氮量为180~240kg·hm-2,灌2水时适宜施氮量为240kg·hm-2。     

施氮量对茶树生长及叶片光合特性的影响

采用水泥池培育的方法,研究了不同氮肥施用量对茶树生长和叶片光合特性的影响。试验设置4个施氮水平,分别为0kg N/hm2（CK）、112.5 kg N/hm2（N1）、225 kg N/hm2（N2）和450 kg N/hm2（N3）。结果表明：施氮显著促进茶树生长,施氮处理茶叶产量比CK显著提高116.98%～141.51%（P〈0.05）,但施氮处理间差异不显著（P〉0.05）;施氮处理茶树叶片叶绿素总量提高30.56%～72.67%,类胡萝卜素含量降低13.37%～29.74%,并与CK差异显著（P〈0.05）;施氮处理茶树叶片净光合速率比CK显著提高14.88%～17.26%（P〈0.05）,但施氮处理间差异不显著（P〉0.05）;氮肥施用提高茶树叶片气孔导度、蒸腾速率和水分利用效率。适量的施氮可提高茶树叶片叶绿素含量、提高光合速率,促进茶树生长和茶叶产量提高;但随着氮肥施用量的增加,单位氮肥对茶树生长的促进效应降低。     

氮肥运筹对稻茬小麦干物质、氮素转运及氮素平衡的影响

为给稻茬小麦高产、优质栽培中合理施氮提供依据,以低蛋白小麦品种宁麦9号和高蛋白小麦品种豫麦34号为材料,设置不同施氮水平(0、150、225和300 kg·hm-2)及基追比(基肥∶追肥为1∶9、3∶7、5∶5和7∶3),研究氮肥运筹对小麦植株C-N积累与转运规律、产量、蛋白质含量及氮素利用的影响。结果表明,适当增加施氮量及追肥比例可同步提高两小麦品种籽粒产量和蛋白质含量。随施氮量和追肥比例的增加,两品种干物质转运量均呈先增后降的趋势,而干物质转运效率及其对籽粒产量的贡献率则显著降低。营养器官氮素转运量随施氮量增加而增加,随追肥比例增加先增后降;氮素转运率及其对籽粒氮素贡献率则随施氮量和追肥比例增加而下降。相关分析表明,提高花后干物质积累是提高小麦产量的重要途径,而促进花前营养器官贮存氮素向籽粒的转运是提高小麦蛋白质含量的重要措施。增加施氮量和基肥比例显著增加了两品种氮素的表观损失量并降低了氮素利用效率。本试验条件下,增施氮肥至225 kg·hm-2,追肥比例宁麦9号≤50%、豫麦34号为50%～70%可同步提高两品种籽粒产量、品质和氮素利用效率,降低氮素损失。     

茶树氮磷钾营养的品种间差异 Ⅰ.氮肥在茶树品种间的生长和生理效应

采用大田和盆栽试验相结合的方法,研究了氮素对茶树不同品种在产量、品质及生长、生理上的效应。结果表明,适量的施氮对各品种的产量和品质均有较好的促进作用,而过量施氮则对品质不利,肥料增产率也下降。过量的氮肥还会使茶树产生肥害,其中苹云、碧峰等大叶品种尤为敏感,而肥害又只能经过茶树自身的生长稀释才能解除。施氮后,新梢叶片中的硝酸还原酶活性、叶绿素含量和含氮化合物含量在小叶品种中增加的幅度较大,而淀粉和蛋白质含量的增加在品种间并未表现出明显的规律,可溶性糖的含量反而下降。此外,还对茶树氮素营养品种间差异的原因以及提高氮素利用率等问题进行了讨论。     

锌钼营养对苦瓜产量、品质及叶片氮素代谢的影响

采用田间试验、植株生理生化测定方法，研究了锌钼营养对苦瓜(品种株洲长白)产量、品质及叶片氮素代谢的影响。结果表明：在土壤缺锌、钼的条件下，叶面喷施一定范围质量浓度配比的硫酸锌和钼酸钠均可显提高苦瓜产量，并可提高苦瓜蛋白质、可溶性糖、维生素C(Vc)和17种氨基酸，尤其是人体必需氨基酸含量，降低NO3^-含量，改善苦瓜品质；锌钼营养还可提高叶片蛋白质、核酸含量以及硝酸还原酶(NR)活性，并降低游离氨基酸、NO3^-含量和核糖核酸酶(RNase)活性。在对叶片氮素代谢的影响程度上，锌和钼的作用存在一定的差异，且锌和钼呈现相互促进作用。苦瓜产量与叶片NR活性，叶片蛋白质与硝酸还原酶活性、核酸含量呈极显正相关，而苦瓜产量与叶片RNase活性、叶片蛋白质与游离氨基酸、叶片核酸与RNase活性、叶片NO3^-含量与硝酸还原酶活性等两两相互间则呈极显负相关。讨论了锌钼对苦瓜品质和氮代谢的影响机理。     

In vitro reproduction in the annual pasture legumes subterranean clover (Trifolium subterraneum L.) and French serradella (Ornithopus sativus Brot.)

Pasture legumes are important components of both mixed farming rotations and permanent pastures in temperate climates. Breeding of two widely sown pasture legumes, subterranean clover (Trifolium subterraneum L.) and French serradella (Ornithopus sativus Brot.), is constrained by the long generation cycle, typically enabling only one generation per year. We hypothesized manipulation of culture medium and conditions would enable the development of a laboratory‐based protocol for in vitro reproduction in subterranean clover and French serradella. In vitro flowering and viable seed set was induced from both species. For subterranean clover, the most effective treatment was culturing on modified MS medium with 1 μm kinetin and 0·1 m sucrose under a 100 μmol m^?2 s^?1 light intensity and continuous photoperiod. For French serradella, culture on a hormone‐free B5 medium with 5 mm NH₄Cl and 0·1 m sucrose under a 100 μmol m^?2 s^?1 light intensity and 20 h photoperiod was optimum. It is expected this technique will have application in accelerating generation turnover within breeding programs, for the study of factors influencing flowering in pasture legumes, and for the propagation of valuable yet enfeebled plants such as embryo‐rescued hybrids.     

Estimation of lucerne yield stability for enabling effective cultivar selection under rainfed conditions

Evaluation of crop and forage yield stability is of increasing relevance in the context of current and recent environmental changes but, in contrast to other field crops, there are no published systematic analyses among forage crops in Europe. A study of stability performance was conducted with 13 Czech cultivars of lucerne at four locations over a 2‐year period with the following aims: (a) to evaluate yield stability of varieties across different environments and (b) to calculate measurable benefits of variety selection in relation to the specific environment. The cultivar Vlasta was identified as the highest yielding cultivar (annual yield 16.0 t DM/ha), whereas the lowest yielding cv. Magda, Tereza and Oslava averaged around 14.9 t DM/ha. Effect of genotype × environment interaction (G × E) was two times higher than for genotype alone. Additive main effects and the multiplicative interaction (AMMI) model showed that the highest yielding cultivars may not be stable across environments. This study demonstrated further that significant yield improvement could be detected, even among a relatively homogenous group of domestic cultivars, and this was driven mainly by site productivity: the improvement was +10% in low‐yielding sites, compared with +3% in high‐yielding sites. Results highlight that advanced agronomy should also consider stability parameters such as AMMI stability value or superiority measures for forage crops in response to the challenges associated with climate change.     

稻文化的再思考3:稻与社稷——印度、泰国等东南亚、南亚主要国家

东南亚、南亚地区是世界上重要的稻米产区,稻米在民众饮食生活和国家社会政治中占有重要地位,民众生活中也保存了非常悠久和丰富的稻作文化习俗及稻谷起源神话传说。本文分析了水稻在东南亚、南亚主要国家印度、印度尼西亚、泰国、越南、菲律宾、孟加拉国、缅甸的作用、地位、生产、消费、文化等情况,并指出了印度、印度尼西亚稻文化的主要标志。     

Model of wheat yield response to application of diclofop-methyl to control ryegrass (Lolium rigidum)

A general model of crop yield response to herbicide application is proposed. The model includes three components: the effect of herbicide dosage on weed density, the effect of surviving weed density on crop yield and the effect of herbicide directly on the crop. The model is used to estimate the response of wheat yield to application of diclofop-methyl to control ryegrass (Lolium rigidum) in Australia. It is found that the competitiveness of ryegrass plants surviving treatment is reduced by the treatment and that the proportion of yield loss at a given ryegrass density is not independent of the absolute weed-free yield. The response function is used to calculate economic thresholds and optimal herbicide dosages.     

大豆对钼与氮、磷、钾的吸收分配动态及相互关系的初步研究

大豆植株中其叶片的钼、氮、磷含量均高于茎杆、叶柄、繁殖器官高于营养器官。钾在整个生育期中都保持较高的水平,只是叶片中的含量低于其它器官。种子中的钼、氮、磷、钾含量都较高。大豆吸收钼及氮、磷、钾的数量因品种及各生育阶段而有差异,吸收量以结荚至鼓粒期为最多,鼓粒期以后,安农75—59的植株中氮、磷、钾吸收量明显下降,唯有钼还在继续吸收,而安激一号对钼及氮、磷、钾仍在吸收。大豆对钼与氮、磷、钾的吸收呈极显著的直线相关,尤其是钼与氮相关最明显。安农75—59亩产189.5kg,需要N素16.05kg,P_2O_54.25kg,K_2O8.43kg,微量元素Mo357.32mg。安激一号亩产214.5kg.需要N素18.00kg、P_2O_55.01kg、K_2O8.85kg、微量元素Mo449.57mg。安激一号的种子除糖、脂肪含量较低外,而氮、磷、钾、钼、维生素C的含量均高于安农75 59。     

基于颜色和形状的茶叶计算机识别研究

综合利用计算机视觉、图像处理技术,增加茶叶的形状参数,改进神经网络算法,实现了茶叶品质识别的自动化。研究中通过数码相机等直接得到茶叶图像,经过对图像格式进行转换和预处理,然后基于HSI模型提取的茶叶颜色特征参数和二值化后图像提取的茶叶形状特征参数,通过遗传神经网络,最后完成对茶叶的自动识别。实验结果表明此方法能取得更好的识别效果,计算机的检测结果与人工检测结果高度吻合。     

Blackgram fiber (Phaseolus mungo): Mechanism of hypoglycemic action

The effect of the administration of blackgram fiber (Phaseolusmungo) on the metabolism of carbohydrates was studied in rats fed 30%NDF (neutral detergent fiber) diet. The experimental group showed a significant increase in liverglycogen level and a significant decrease in blood glucose. Significantincreases in the activities of glycogen phosphorylase, hexokinase, fructose-1,6-diphosphatase, glucose-6-phosphate dehydrogenase and isocitratedehydrogenase were observed in the experimental group. The activities ofphosphoglucomutase and glucose-6-phosphatase were significantly lower inrats fed the fiber diet. The study showed that blackgram fiber exhibitssignificant hypoglycemic action in experimental animals.     

Carbohydrase systems of Saccharophagus degradans degrading marine complex polysaccharides

Saccharophagus degradans 2-40 is a γ-subgroup proteobacterium capable of using many of the complex polysaccharides found in the marine environment for growth. To utilize these complex polysaccharides, this bacterium produces a plethora of carbohydrases dedicated to the processing of a carbohydrate class. Aiding in the identification of the contributing genes and enzymes is the known genome sequence for this bacterium. This review catalogs the genes and enzymes of the S. degradans genome that are likely to function in the systems for the utilization of agar, alginate, α- and β-glucans, chitin, mannans, pectins, and xylans and discusses the cell biology and genetics of each system as it functions to transfer carbon back to the bacterium.     

Grain number dominates grain weight in temperate cereal yield determination: Evidence based on 30 years of multi-location trials

Multi-location data collected over 30 years in Finland on major cereal crops (spring barley, oat and wheat, and winter wheat and rye) provide an opportunity to characterise variation, interrelation and relative importance of the grain yield determining components, grain number per square meter (GNO) and single grain weight (SGW). In addition to evaluating differences among cereal crops in yield determination, changes among different age groups (AG) were compared. Field experiments were carried out in 1970–2001 at 25 locations in Finland. Grain yield was recorded (at 15% moisture) and SGW (mg) and GNO (number m⁻²) determined. Frequencies of different GNO and SGW combinations were analysed for all crops and component means in different yield groups as well as among four AGs. In most cases GNO dominated SGW, representing the major yield component determining grain yield. GNO was highly responsive to favourable growth conditions. The change in GNO was especially high when recurrent, relatively low yield groups were compared, while at higher yields the role of SGW became increasingly important, but did not exceed that of GNO. The degree of GNO domination varied according to crop. Increased grain yield in spring oat and winter rye was associated with higher numbers of set grain, while spring barley and winter wheat responded to yield favouring conditions also through higher SGW. Despite GNO dominated SGW due to its responsiveness to growing conditions, its role in yield improvement was not obvious when the entries (n ≥ 30) were classified into four AGs. Improvements in grain yield derived from AG were associated with crop-specific GNO and/or SGW changes.     

The Challenge of Ecophysiological Biodiversity for Biotechnological Applications of Marine Microalgae

In this review, we aim to explore the potential of microalgal biodiversity and ecology for biotechnological use. A deeper exploration of the biodiversity richness and ecophysiological properties of microalgae is crucial for enhancing their use for applicative purposes. After describing the actual biotechnological use of microalgae, we consider the multiple faces of taxonomical, morphological, functional and ecophysiological biodiversity of these organisms, and investigate how these properties could better serve the biotechnological field. Lastly, we propose new approaches to enhancing microalgal growth, photosynthesis, and synthesis of valuable products used in biotechnological fields, mainly focusing on culture conditions, especially light manipulations and genetic modifications.