Biotic interactions affecting potato production

Pest/pathogen interactions affecting potato production are reviewed. Many reported interactions in potatoes and other crops are best termed associations or interrelationships. True synergistics interactions can be expressed as Y = b₁ x₁ + b₂ x₂ + b₃ (x₁ x₂) + - b_n x_n + e in which Y is a measure of plant growth, b₁, b₂, b_n are constants, x₁, x₂, x_n are independent variables and e is the error term. Examples of interactions including pathogen vectors, and various interactions involving different viruses and biotic taxa and among biotic taxa (e.g., virus-virus, virus-fungus, fungusbacteria, and nematode-fungus) in potatoes are cited. It is included that important interactions do occur in potato production systems and that additional research is needed to identify unknown interacting factors and to elucidate mechanisms of those previously described. Particular needs exist for holistic or synoptic studies to identify the role of interacting factors in total crop management.     

Preparation and photocatalytic activity of bismuth tungstate coated polyester fabric

Bi₂WO₆ particles were prepared and then coated on the polyester fabric. Surface morphology, crystal structure, and chemical structure of the Bi₂WO₆ particle coated polyester fabric were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Photocatalytic activity was evaluated by the degradation of methylene blue (MB) under ultraviolet light irradiation. Influences of the different concentrations of Bi₂WO₆ on the deposit weight and the photocatalytic activity of the Bi₂WO₆ particle coated polyester fabric were investigated. In addition, UV protection of the Bi₂WO₆ particle coated polyester fabric was examined. The results show that Bi₂WO₆ particles are uniformly coated on the surface of the polyester fabric. The Bi₂WO₆ particles coated on the polyester fabric are irregular and are orthorhombic. In addition, the Bi₂WO₆ particle coated polyester fabric exhibits excellent photocatalytic activity and UV protection. The average degradation efficiency of MB in the presence of the Bi₂WO₆ particle on the polyester fabric coated with 10 g/l Bi₂WO₆ reaches 98.6 % after being illuminated for 7 h. Therefore, the Bi₂WO₆ particle coated polyester fabric shows excellent photocatalytic stability for dyes degradation.     

Variability in grass forage quality and quantity in response to elevated CO2 and water limitation

Global climate change is expected to alter carbon dioxide concentration ([CO₂]) and water availability, with uncertain impacts on agriculture. Forage quality and quantity in grazing systems are of particular concern because C₃ and C₄ plants respond differently to altered environmental conditions. In a growth chamber, we compared crude protein content, biomass recovery and total crude protein across a set of perennial C₃ and C₄ grasses from the northern U.S. Great Plains under elevated [CO₂] and simulated drought. Simulated 95% confidence intervals indicate both C₃ and C₄ grasses increased forage quality and quantity under elevated [CO₂]. C₄ grasses were generally resistant to water limitation while forage quality and quantity of C₃ grasses declined under simulated drought. Our results are consistent with literature on forage quantity responses to elevated [CO₂] and drought, but forage quality responses contradict expectations. We suggest measuring plant functional traits might better elucidate response mechanisms and ameliorate methodological differences even if traits are not directly applicable to grazing management.     

Structural characterization of stalk lignin from banana plant

Dioxane lignins from two fractions of banana plant ‘Dwarf Cavendish’ stalk (floral stalk (DL_FS) and rachis (DL_R)) were structurally characterized by a set of spectroscopic (Ultraviolet (UV), FTIR, solid- and liquid-state NMR) and chemical degradation (permanganate (PO) and nitrobenzene oxidation (NO)) techniques. Despite both lignins are of HGS-type, strong structural differences were observed between them. Thus, DL_FS showed almost twice the abundance of H and G units and almost half of the abundance of S units when compared to DL_R. DL_R possessed significantly higher amount of β-O-4′ structures (0.32/C₆ against 0.12/C₆) and the molecular weight (5400 Da against 3750 Da) than those of DL_FS. About 72% of the condensed structures in DL_FS are of β-5 and 5–5′ types, whereas 4-O-5′-diaryl ether structures were the most abundant condensed structures in DL_R. Most of H units in both lignins are terminal phenolic coumarates linked to lignin substructures by ester bonds. Both lignins are structurally associated with suberin-like components in cell wall tissues. Structural features of stalk lignin were discussed in terms of possible restrictions for the kraft pulping of integral stem material.     

Gas Separation Polysulfone Membranes Modified by Cadmium-based Nanoparticles

This paper presents new mixed-matrix membranes (MMMs) synthesized via incorporating hexamethylenetetramine dicyanamide cadmium nanoparticles, a metal organic framework (MOF), into the polysulfone (PSF) matrix. The MMMs are characterized using FTIR and SEM analyses, and their gas permeation properties are evaluated at different MOF loadings and various pressures. The results show that the nanoparticle is compatible with the polymer and distributes homogenously in the matrix. Compared to the pristine PSF membrane, the MMM with 2.5 wt. % of the MOF nanoparticles has lower CO₂, CH₄, N₂ and O₂ permeabilities but significantly higher CO₂/CH₄, CO₂/N₂ and O₂/N₂ gas pair selectivities (i.e., 41.66, 20.08 and 5.09, respectively, which are 42.6, 61.6 and 60.02 % higher). As the total pressure increases, the gas permeabilities of the pristine PSF membrane and the MMMs decrease, but their sieving abilities increase. These results suggest that gas selectivities of high free-volume polymers with poor sieving abilities can be improved by incorporating the MOF into the polymer.     

More lightweight and isodiametric seeds for C4 than for C3 grasses are associated with preference for open habitats of C4 grasses in a temperate flora

Seed mass and shape of grasses were analysed in a temperate flora containing 178 and 26 species belonging to C₃ and C₄ photosynthetic types respectively. The weedy character and the annual or perennial status were also considered. On the basis of the seed traits studied, three groups were distinguished: C₄ grasses, annual C₃ grasses of weedy character and perennial non‐weedy C₃ grasses. The C₄ group had more isodiametric (same diameter in all directions) seed shape and lower average seed mass than the C₃ group. To our knowledge, this has not yet been described for temperate C₄ grasses and is certainly associated with their preference for open habitats where competition for light is small. Weedy annual C₃ grasses had heavier and less isodiametric seeds than C₄ grasses did. These species are mostly specialized to establish in the dense cover of perennial vegetation, and this ability distinguishes them from the C₄ group. Non‐weedy perennial C₃ species possessed less isodiametric seeds than did C₄ grasses, but did not differ from weedy annual C₃ grasses. As most alien C₄ grasses naturalized in Hungary are annuals with small, isodiametric seeds, these traits are good candidates to be included in screening for potential future invasives in open habitats.     

Potato Stolon and Tuber Growth Influenced by Nitrogen Form

Abstract

Potato tuber initiation and its growth are key processes determining tuber yield, which are closely related to stolon growth, and are influenced by many factors including N nutrition. We investigated the influences of different forms of nitrogen (N) on stolon and tuber growth in sand culture with a nitrification inhibitor during 2010 – 2011, and using two potato cultivars. Plants supplied with NO₃-N (N as nitrate, NO₃^-) produced more and thicker stolons than those supplied with NH₄-N (N as ammonium, NH₄⁺) at tuber initiation stage. In the plants fed NO₃-N, the stolon tips swelled or formed tubers earlier and produced more tubers than in those fed with NH₄-N. However, no significant difference was observed among N forms in terms of tuber yield at harvest, this may have been because of the shoot growth rate at tuber initiation stage was lower in the plants fed NO₃-N. During the tuber bulking stage, the difference in shoot DWs among N forms began to decrease, and the shoot DW of plants fed NO₃-N was even heavier than those fed NH₄-N in some cases. The influence of N form on potato plant growth may therefore vary with the potato growth stage.     

Effect of Freezing Technology and Storage Conditions on Folate Content in Selected Vegetables

Folates (B vitamins) are essential for the proper function of many bodily processes. Although a rich natural source are vegetables, the literature lacks data on the effect of the pre-treatment and freezing technologies used in vegetable processing and frozen storage time on the folate content in these materials. Moreover, since folates are very unstable nutrients, the amount available in processed and stored foods can be significantly lower than in raw products. In tested vegetables (green beans, yellow beans, peas, cauliflower, broccoli and spinach), one folate form was identified, 5-methyltetrahydrofolate (5-CH₃-H₄folate). It was observed that pre-treatment and freezing technology significantly (p?<?0.05) decreased 5-CH₃-H₄folate content only in vegetables with the largest degree of fragmentation (cut and briquetted spinach) and the smallest size (peas). In all analyzed samples, the 5-CH₃-H₄folate content decreased with the time of frozen storage. In frozen cauliflower, the 5-CH₃-H₄folate loss exceeded 95 % compared to the fresh product just after the third month of frozen storage. Meanwhile, in green and yellow beans, significant 5-CH₃-H₄folate losses (at the level of 75 % and 95 %, respectively) were observed no earlier than after the 9th month of frozen storage.     

Quantitative estimation of accumulation of protein fractions in unripe and ripe maize grain

The changes in amounts per grain of six protein fractions isolated by selective extraction, which had been determined during the development of INRA 260 and opaque 2 maize grains, were again studied by taking as development variable the mount of total protein per grain (N_p), defined as the difference between total and non protein nitrogen content. The accumulation of each protein fraction in grain is depicted with one straight line or aseries of linear segments whose slopes represent the relative rates of accumulation of each fraction with reference to that of total protein. According to changes in the slopes, four phases of accumulation can be distinguished for the INRA 260 variety. Phase I is characterized by the presence of basic proteins (salt-soluble proteins, G₃ glutclins and residue) alone. During phase II, which begins with the synthesis of endosperm specific proteins (zeins, G₁ and G₂ glutelins), all protein fractions are accumulated. Phases III and IV are concerned with the changes in accumulation of fractions belonging to basic proteins. With opaque 2 variety, phases II, III and IV cannot be differentiated. For a given variety v and from the second phase, the amount N_i,v of basic proteins, zeins, G₁ and G₂ glutelins is related to N_p by the equation N_i,v=a_p,i,v+b_p,i,vN_p where a_p,i,v and b_p,i,v remain constant throughout development and are independent on cultural pratices. This equation also represents the phenotypic of fraction i as function of total protein of mature grain. Similar equations for expressing the intra- and intervarietal changes of protein fractions as function of total nitrogen content of ripe grain can be found.     

Perspective on the relative insignificance of increasing atmospheric CO2 concentration to crop yield

Average yield of most crops in many countries increased significantly during the past 50 to 100 years. Although atmospheric CO₂ concentration, [CO₂]_a, also increased during that time period, and although crop growth and yield can respond positively to [CO₂]_a increase, yield increases were due mainly to factors other than increasing [CO₂]_a. Similarly, some yield increases prior to 1900 were also associated primarily with factors other than changes in [CO₂]_a. In particular, past national average yield increases were the result chiefly of technological advances such as nitrogen fertilization; selection of genotypes with increased harvest index and disease resistance; mechanization of planting, cultivation, and harvesting; and chemical weed and pest control. If technology continues to increase average yields at recent rates, near-future increases in [CO₂]_a will have only small impacts on yield in comparison to technology in many countries. Conversely, if future increases in [CO₂]_a are the main drivers of future yield increases, those yield increases will be small. These points are demonstrated through a comparison of (i) long-term records of yield, (ii) data from key controlled-[CO₂] experiments, and (iii) records of past [CO₂]_a. Finally, it is noted that continued [CO₂]_a increase may bring with it climatic changes that could have negative or positive impacts on future yield.     

A molecular dynamics simulation on the self-assembly of ABC triblock copolymers. 2. Effects of block sequence

The effect of block sequence on the self-assembly of ABC-type triblock copolymers in the ordered state is investigated using an isothermal-isobaric molecular dynamics simulation. The block sequence has an important effect on the morphology of ABC triblock copolymers. Different morphologies are observed depending on the block sequence as well as the block composition. The triblock copolymers with the volume fraction of 1:1:1 (f _A=f _B=f _C=0.33) show the three phase and four layered lamellar structures irrespective of the block sequence. The A₃₂B₁₆C₃₂ triblock copolymer withf _B=0.2 shows a morphology in which cylinders of midblock B are formed at the interface between A and C lamellae, whereas the morphology of triblock copolymer B₁₆C₃₂A₃₂ and C₃₂A₃₂B₁₆ show a cylindrical core-shell structure and a lamellar type morphology, respectively. The A₂₀B₄₀C₂₀ triblock copolymer with the block B as a major component shows a tricontinuous structure, whereas both B₄₀C₂₀A₂₀ and C₂₀A₂₀B₄₀ triblock copolymers exhibit the lamellar structures. When the block B has larger volume fraction withf _B=0.75, the matrix is composed of block B, and other two blocks A and C form spherical domains.     

Mechanism of High Photosynthetic Capacity in BC2F4 LinesDerived from a Cross between Oryza sativa and Wild Relatives O. rufipogon

Abstract

We found that several BC₂F₄ lines had high leaf photosynthetic rates under light-saturated and ambient CO₂ conditions. These lines are progenies of BC₂F₁ plants with high photosynthetic capacities which were generated by backcrossing between Oryza rufipogon (W630) and O. sativa cv. Nipponbare, as a recurrent parent. Some photosynthetic characteristics of the BC₂F₄ lines were investigated to identify the factors increasing photosynthetic rates. Photosynthetic rates of these lines under light-saturated conditions at 50 to 700 ppm CO₂ concentrations were higher than those in Nipponbare. The estimated-maximum photosynthetic rates under light-saturated and CO₂-saturated conditions in BC₂F₄ lines were also higher than that in Nipponbare. The photosynthetic rate under light-saturated and ambient CO₂ conditions was positively correlated with the carboxylation efficiency as an indicator of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity in vivo rather than stomatal conductance. Initial and total Rubisco activities in vitro tended to be higher in the BC₂F₄ lines than in Nipponbare. The content of active Rubisco calculated from the activation state of Rubisco was also higher in the BC₂F₄ lines than in Nipponbare. These results suggest that high photosynthetic capacities of BC₂F₁ plants can be maintained high in their progenies and high photosynthetic rates under light-saturated and ambient CO₂ conditions in the BC₂F₄ lines are achieved mainly by the high activity of Rubisco due to the high active Rubisco content.     

Homogeneity of the PAN/DMSO/H2O spinning solutions

The homogeneity of PAN/DMSO/H₂O spinning dopes with conventional PAN molecular weight and comparative high PAN concentration have been investigated using rheology method. The rheological results show that G′ and G″ of these solutions increase with increasing oscillation frequency. At lower temperature and higher H₂O content, higher viscous modulus and elastic modulus are observed, too. The homogeneity of PAN/DMSO/H₂O systems is reflected through the logG′-logG″ plots as well as gel point temperatures. The theoretical analysis indicates PAN/DMSO/H₂O spinning solutions with conventional PAN molecular weight are close to homogeneous systems, which are very suitable for gel spinning.     

Improvement of liquid absorption properties of nonwoven polypropylene substrates by low pressure plasma treatment with CH4-O2 mixture gas

The use of nonwoven textile substrates for filtration and absorption purposes is generalized due to the high surface area they can provide. Many of these applications require good wetting properties to increase efficiency. In this work, low pressure plasma treatment with a CH₄-O₂ mixture gas has been used to increase surface wettability and subsequent absorption properties on nonwoven polypropylene substrates. CH₄ plasma treatment leads to a plasma polymerization process which results in hydrophobic surface finishing, but in combination with O₂, it is possible to form a functionalized plasmapolymerized layer thus improving wetting properties. Changes in wetting properties have been studied by contact angle measurements showing that optimum wetting properties are obtained with exposure times to plasma treatment of about 10 min, and no significant changes are obtained for longer exposure times. Absorption efficiency has been followed by determining three different parameters by the guidelines of the UNE-EN-ISO 9073-6 standard: wetting time, liquid absorption capacity (LAC) and liquid propagation rate or absorption speed. All these properties are remarkably improved as the exposure time to CH₄-O₂ plasma increases; this improvement is remarkably high for relatively short exposure times (5?C10 min) and no significant changes are obtained for long exposure times so that, it is possible to conclude that previous plasma treatment with exposure times in the 5?C10 min range is an efficient method to improve overall absorption properties of nonwoven polypropylene substrates.     

Studies on the macromolecular components of nonwood available in Bangladesh

The structural feature of macromolecular component of dhaincha, cotton stalks, jute fiber, rice straw and wheat straw, which are commonly used in paper pulp production in forest deficient countries, was thoroughly studied. Lignin was isolated by classical Bjorkman method and characterized by elemental and methoxyl analysis, alkaline nitrobenzene oxidation, FTIR and ¹H NMR spectroscopy. The C₉ formulas for cotton stalks, jute fiber, dhaincha, rice straw and wheat straw were C₉H_8.95O_3.53(OCH₃)_1.00, C₉H_8.12O_4.03(OCH₃)_1.65, C₉H_8.10O_4.65(OCH₃)_1.32, C₉H_8.58O_3.74(OCH₃)_1.23 and C₉H_8.31O_3.54(OCH₃)_1.23, respectively. The alkaline nitrobenzene oxidation products showed that syringyl to vanilin ratio of these nonwood varied from 1.1 to 2.9. Jute fiber showed the highest syringyl to vanilin ratio that are consistent with C₉ formula. The β-O-4 units in these nonwood lignins had predominately erythro stereochemistry type. The crystalline structure of these nonwood cellulose was also studied using X-ray diffraction and FTIR spectroscopy. The proportions of crystallinity, crystal size were varied from plant to plant. Jute fiber showed the highest proportion of crystallinity (73.4%) and crystal size (4.2 nm). The degree of polymerization of these nonwoods cellulose has also been studied. Degree of polymerization of jute cellulose was also the highest (3875). FTIR spectroscopy showed that these nonwoods cellulose was monoclinic unit cell structure (I_β). Carbohydrate analysis showed that the main sugar component in the hydrolyzates of these nonwoods were xylose apart from glucose.     

小麦籽粒性状的遗传效应分析及其育种策略

大粒性状对于小麦高产育种具有重要意义。为明确大粒型小麦新种质籽粒性状的遗传特性,以漯麦76（大粒型）和L529（小粒型）为亲本构建P₁、P₂、F₁、F₂、B₁和B₂共4个世代6个群体,利用SmartGrain软件获得籽粒性状数据,采用主基因+多基因混合遗传分析方法研究大粒性状的遗传规律。结果表明,千粒重的最佳模型为两对加性-显性-上位性主基因+加性-显性-上位性多基因遗传模型（MX2-ADI-ADI）,籽粒面积和粒长的最佳模型均为加性-显性-上位性多基因遗传模型（PG-ADI）,籽粒周长的最佳模型为两对加性-显性-上位性主基因遗传模型（2MG-ADI）,粒宽的最佳模型为两对加性-显性-上位性主基因+加性显性多基因遗传模型（MX2-ADI-AD）。综上,对大粒性状的选择,应采用“高粒重×高粒重”的组合配制方案构建F₂（单交）和B₂（大粒亲本回交）选择群体,多环境鉴定,以低代宽、高代严的选择标准,在高代对大粒性状进行选择。     

Calculation of theoretical nitrogen rate for simple nitrogen recommendations in intensive cropping systems: A case study on the North China Plain

Nitrogen (N) is a crucial nutrient that requires careful management in intensive cropping systems because of its diverse beneficial and detrimental effects. Here we propose the concept of theoretical N rate (TNR) to answer the important question of how much fertilizer N should be applied to intensive systems based on the N fluxes due to transformation processes in the soil-crop-environment continuum. We define TNR as the theoretically calculated fertilizer N rate with the quantitative relationships of the core N fluxes among fertilizer N, soil N and crop uptake N in the crop root zone to obtain high target yield, maintain soil N balance and minimize environmental risk. We deduced one basic mathematical expression (N_fert = N_uptake − N_straw + N_fert3) and two simplified expressions [N_fert = (N_uptake − N_straw)/(1 − Coeff); N_fert ≅ N_uptake] for calculating the TNR. These expressions do not need much field experimentation or elaborate soil and plant testing to obtain information on crop N demand and soil N supply, and are simple to implement in farming practice to provide a very cost-effective approach. We consider this scheme to be a useful contribution to rational fertilizer practice, especially in developing countries where other N recommendation systems are usually not available and agricultural extension services are poorly developed or absent.     

一个玉米无叶舌突变体Y43的遗传分析

在EMS法构建的玉米骨干自交系昌7-2突变体文库中,发现了一个玉米无叶舌突变体,随后通过连续自交,获得了纯合一致、稳定遗传的无叶舌自交系,命名为Y43。该突变体穗上部叶片直冲,表现为无叶舌,其他农艺性状与受体一致。通过对Y43与昌7-2及海9-21的F1、F2、BC1分析,初步确定该突变体无叶舌性状受一对隐性单基因控制。     

Presence of chloroplasts in mestome sheath cells of the C3 Pooid grass Elymus tsukushiensis

ABSTRACT

The successful introduction of the C₄ pathway into C₃ crops would increase photosynthetic rates and crop productivity. However, our poor understanding of how Kranz leaf anatomy develops poses a great obstacle. In particular, the origin, development, and genetics of bundle sheath (BS) cells in C₄ plants are key points to elucidate. Here we report that Elymus tsukushiensis, a common C₃ grass of the subfamily Pooideae, contains chloroplasts in the mestome sheath (MS) cells of the leaf, unlike most MS cells of C₃ grasses. The chloroplasts are smaller than those of mesophyll cells. Immunogold localization showed that the chloroplasts and mitochondria of MS cells, respectively, accumulate ribulose 1,5-bisphosphate carboxylase/oxygenase and a photorespiratory enzyme, glycine decarboxylase, as in mesophyll cells. Thus, we suggest that the MS cells have weak photosynthetic and photorespiratory functions. This finding provides an insight into the development and evolution of C₄-type BS cells in leaves of C₃ grasses.