Plant Product Quality Research Articles

Image Processing Based Detection of Fungal Diseases in Plants

This paper presents a study on the image processing techniques used to identify and classify fungal disease symptoms affected on different agriculture/horticulture crops. Computers have been used to mechanization, automation, and to develop decision support system for taking strategic decision on the agricultural production and protection research. The plant disease diagnosis is limited by the human visual capabilities because most of the first symptoms are microscopic. As plant health monitoring is still carried out by humans due to the visual nature of the plant monitoring task, computer vision techniques seem to be well adapted. One of the areas considered here is the processing of images of disease affected agriculture/horticulture crops. The quantity and quality of plant products gets reduced by plant diseases. The goal is to detect, to identify, and to accurately quantify the first symptoms of diseases. Plant diseases are caused by bacteria, fungi, virus, nematodes, etc., of which fungi is the main disease causing organism. Focus has been done on the early detection of fungal disease based on the symptoms.

Iron nutrition, biomass production, and plant product quality.

One of the grand challenges in modern agriculture is increasing biomass production, while improving plant product quality, in a sustainable way. Of the minerals, iron (Fe) plays a major role in this process because it is essential both for plant productivity and for the quality of their products. Fe homeostasis is an important determinant of photosynthetic efficiency in algae and higher plants, and we review here the impact of Fe limitation or excess on the structure and function of the photosynthetic apparatus. We also discuss the agronomic, plant breeding, and transgenic approaches that are used to remediate Fe deficiency of plants on calcareous soils, and suggest ways to increase the Fe content and bioavailability of the edible parts of crops to improve human diet.

Biochar and biochar-compost as soil amendments to a vineyard soil: Influences on plant growth, nutrient uptake, plant health and grape quality

Most European vineyard soils exhibit low soil fertility. They are highly vulnerable to erosion, low in soil organic matter content and, therefore, in water holding capacity and nitrate retention. The applications of biochar and biochar-compost are said to address some of these issues. We tested the ability of these amendments to improve soil quality and plant production quality in a 30-year-old vineyard in Valais, Switzerland. The amendments of biochar alone (8tha−1, produced from wood at 500°C), aerobic compost (55tha−1) and biochar-compost (8tha−1+55tha−1, mixed before the composting process) were compared to an un-amended control soil. During the years 2011, 2012 and 2013 various vine and green cover growth, vine health and grape quality parameters were monitored. Biochar and biochar-compost treatments induced only small, economically irrelevant and mostly non-significant effects over the three years. We concluded that topsoil application of higher amounts of biochar has no immediate economic value for vine growing in poor fertility, alkaline, temperate soil.

Granivory reduces biomass and lignin concentrations of plant tissue during grassland assembly

Small mammals can influence grassland assembly by selecting against palatable plants – the community can become dominated by the plants they avoid. This predation-based selection could have indirect effects on community biomass and tissue quality, especially given how untasty plants may have higher concentrations of recalcitrant carbon compounds including lignin. We tested small mammal effects on biomass and tissue quality of roots and shoots in a two-year-old 18ha restored tallgrass prairie with established zones of high and low plant predation. We focused on the three dominant herbaceous functional groups of tallgrass prairie (perennial forbs, C3 and C4 grasses), and targeted the early stages of assembly given that plant predation by small animals can unfold quickly and is difficult to subsequently quantify. We predicted rodent predation to create communities with reduced biomass but an increased abundance of lignin-rich plants; we only observed the former. Rodents reduced aboveground biomass by 46% but preferentially targeted lignin-rich plants, with the latter result explained by the predominance of granivory over herbivory – there was no opportunity for selection based on tissue palatability. Based strictly on aboveground biomass, we estimated small mammals reduced standing stocks of recalcitrant carbon by 65kgha−1, with reductions in belowground stocks almost certainly higher given that root:shoot ratios averaged 21:1. Given that the quantity and quality of plant production can affect ecosystem functions including decomposition and the regulation of soil carbon stocks, our work suggests that non-random plant predation may substantially affect rates of soil carbon accumulation in the early stages of grassland development.

Plant growth promotion by 18:0-lyso-phosphatidylethanolamine involves senescence delay

Lyso-phosphatidylethanolamine (LPE) is a minor membrane glycerolipid and egg-derived 18:0-LPE is used commercially as a plant bio-regulator to improve plant product quality. Physiological responses initiated by LPE treatment included delayed senescence in leaves and fruits, improved shelf-life of products post harvest, and mitigation of ethylene-induced process. However, the biochemical and molecular mechanisms underlying LPE-induced responses in plants and harvested plant parts remain unclear. In this paper, commentary is presented on the effects of LPE at the biochemical level in an effort to develop a mode of action. Implications, although tentative, are that LPE exerts its effect via lipid-protein interaction to attenuate ethylene (ETH)-mediated responses and impact pathogenesis-related proteins which together delay senescence progression.

Lorenz Hiltner, a pioneer in rhizosphere microbial ecology and soil bacteriology research

Lorenz Hiltner is recognized as the first scientist to coin the term “rhizosphere” in 1904. His scientific career and achievements are summarized in this essay. Most of his research he performed in the Bavarian Agriculture–Botanical Institute (later named the “Bavarian Institute of Plant Growth and Plant Protection”) in Munich, where he was the director from 1902 to 1923. Beginning with intensive and thorough investigations on the germination and growth of different crop plants (legumes and non-legumes) Hiltner became convinced, that root exudates of different plants support the development of different bacterial communities. His definition of the “rhizosphere” in the year 1904 centered on the idea, that plant nutrition is considerably influenced by the microbial composition of the rhizosphere. Hiltner observed bacterial cells even inside the rhizodermis of healthy roots. In analogy with fungal root symbionts, Hiltner named the bacterial community that is closely associated with roots “bacteriorhiza.” In his rhizosphere concept, Hiltner also envisioned, that beneficial bacteria are not only attracted by the root exudates but that there are also “uninvited guests,” that adjust to the specific root exudates. Based on his observations he hypothesized that “the resistance of plants towards pathogenesis is dependent on the composition of the rhizosphere microflora.” He even had the idea, that the quality of plant products may be dependent on the composition of the root microflora. In addition to his scientific achievements, Hiltner was very dedicated to applied work. Together with F. Nobbe he had the first patent on Rhizobium inoculants (Nitragin). He continuously improved formulations and the effectivity of the Rhizobium preparations and he also initiated seed dressing with sublimate for plant protection of seedlings. Thus, Hiltner tightly linked breakthroughs in basic research to improved rhizosphere management practices. In addition, he wrote a pioneering monograph on plant protection for everybody’s practical use. His emphasis on understanding microbes in the context of their micro-habitat, the rhizosphere, made him a pioneer in microbial ecology. Even now, in the era of genome and postgenome analysis with our better understanding of plant nutrition and soil bacteriology, his ideas and contributions are as fresh as they were more than 100 years ago.

Polyphenols as Potential Indicators for Drought Tolerance in Tea (Camellia sinensisL.)

Plant polyphenols have gained prominence in quality of plant products and in human health. An experiment was conducted to determine the association of tea polyphenols with water stress and their suitability as indicators for drought tolerance. The experiment was conducted in a 'rain-out' shelter, and consisted of six tea clones (BBK 35, TRFK 6/8, TRFK 76/1, TRFK 395/2, TRFK 31/30, and TRFK 311/287) and four levels of soil water contents (38, 30, 22, and 14% v/v), which were maintained for a period of 12 weeks. The treatments were arranged in a completely randomized design and replicated three times. Plant growth was monitored over 6 weeks, and a water stress index was calculated to determine water-stress tolerant clones. Total polyphenols in tea shoots was analyzed and a regression analysis done. The results indicate that declining soil water content (SWC) reduced both growth and content of polyphenols in tea. Tolerant clones maintained a high polyphenol content at low SWC, and also showed less fluctuation in phenolics when subjected to changes in SWC. There was significant (P<0.001) correlation of total polyphenol content with shoot growth and WSI of tea, and a linear relationship (r2=0.97) between SWC for tea and both, water stress index and shoot polyphenol content. We report that there is a potential to use polyphenols as indicators for selection of drought-tolerant tea cultivars.

Quality of plant products from organic agriculture

AbstractDuring the last decade, consumers' trust in food quality has decreased drastically, mainly because of growing ecological awareness and several food scandals (e.g. BSE, dioxins, bacterial contamination). It has been found that intensive conventional agriculture can introduce contaminants into the food chain. Consumers have started to look for safer and better controlled foods produced in more environmentally friendly, authentic and local systems. Organically produced foods are widely believed to satisfy the above demands, leading to lower environmental impacts and higher nutritive values. So far, studies have partly confirmed this opinion. Organic crops contain fewer nitrates, nitrites and pesticide residues but, as a rule, more dry matter, vitamin C, phenolic compounds, essential amino acids and total sugars than conventional crops. Organic crops also contain statistically more mineral compounds and usually have better sensory and long‐term storage qualities. However, there are also some negatives: plants cultivated in organic systems generally have 20% lower yields than conventionally produced crops. Several important problems need to be addressed in the coming years: environmental, bacterial and fungal contamination of organic crops and, the most essential issue, the impact of organic food consumption on animal and human health. Copyright © 2007 Society of Chemical Industry

Coal preparation plant optimization: A critical review of the existing methods

A coal preparation plant typically operates with multiple cleaning circuits to clean individual size fractions of run-of-mine coal. Coal preparation plants are traditionally optimized using the equalization of incremental product quality approach. Individual cleaning circuits are operated at the same specific incremental product quality so that the targeted overall plant product quality is achieved. Over the years, it has been well established that equal incremental product quality approach maximizes plant-yield for a given product quality constraint. However, while dealing with multiple quality constraints, the incremental quality approach may not provide a complete solution to the optimization problem. It may be intuitive to realize that the dirtiest particle(s) in a coal product, with respect to ash content, may not be the same particle(s) with respect to sulfur content. Therefore, with increasing number of product quality constraints, which may include (but not limited to) limiting ash, sulfur and trace element contents, the plant has to be optimized based on each incremental product quality. Understandably, the operating points selected for each circuit to maximize plant-yield based on incremental ash content, may not be suitable for obtaining maximum plant yield based on incremental sulfur content. These limitations of the equalization of incremental product quality approach to satisfy multiple product quality constraints have been reviewed in detail in this publication with an example of ash and sulfur data collected from an operating coal preparation plant.

Unraveling the role of mitochondria during oxidative stress in plants.

The sedentary habit of plants means that they must stand and fight environmental stresses that their mobile animal cousins can avoid. A range of these abiotic stresses initiate the production in plant cells of reactive oxygen and nitrogen species that ultimately lead to oxidative damage affecting the yield and quality of plant products. A complex network of enzyme systems, producing and quenching these reactive species operate in different organelles. It is the integration of these compartmented defense systems that coordinates an effective response to the various stresses. Future attempts to improve plant growth or yield must consider the complexity of inter-organelle signaling and protein targeting if they are to be successful in producing plants with resistance to a broad range of stresses. Here we highlight the role of pre-oxidant, antioxidant, and post-oxidant defense systems in plant mitochondria and the potential role of proteins targeted to both mitochondria and chloroplasts, in an integrated defense against oxidative damage in plants.

Genotypic variation in response of quaking aspen (Populus tremuloides) to atmospheric CO2 enrichment.

Enriched atmospheric CO2 alters the quantity and quality of plant production, but how such effects vary among plant genotypes is poorly known. We evaluated the independent and interactive effects of CO2 and nutrient availability on growth, allocation and phytochemistry of six aspen (Populus tremuloides Michx.) genotypes. One-year-old trees, propagated from root cuttings, were grown in CO2-controlled glasshouses for 64days, then harvested. Foliage was analyzed for levels of water, nitrogen, starch, phenolic glycosides and condensed tannins. Of seven plant growth/allocation variables measured, four (biomass production, stem growth, relative growth rate and root:shoot ratio) exhibited marginally to highly significant CO2 × genotype interactions. CO2 enrichment stimulated growth of some genotypes more than others, and this interaction was itself influenced by soil nutrient availability. In addition, enriched CO2 increased the magnitude of the among-genotype variance for four of the growth/allocation variables. Of six foliar chemical constituents analyzed, CO2-mediated responses of two (the phenolic glycoside tremulacin and condensed tannins) varied among genotypes. Moreover, enriched CO2 increased the magnitude of among-genotype variance for four of the chemical variables. Given the importance of these growth and chemical characteristics to the biological fitness of aspen, this research suggests that projected atmospheric CO2 increases are likely to alter the genetic structures and evolutionary trajectories of aspen populations.

Improving plant product quality

Improving plant product quality

Propionibacteria in fermented vegetables

This paper presents the results of the application of propionibacteria (PAB) to the pro- duction of fermented vegetables: sauerkraut, red beet juice and vegetable salads. The addition of PAB to the lactic acid bacteria (LAB) used in the fermentation led to increases in folacin, vitamin BI2, propionic and acetic acid contents, inhibition of harmful and pathogenic microorganisms and the extension of the shelf-life of the products. Products made with PAB usually had better organoleptic characteristics than products made only with LAB. In long fermentations, such as for sauerkraut, substantial amounts of metabolites from PAB were produced during processing and storage. On the other hand, in short fermentations, such as for red beet juice, the concentration of metabolites in the final product depended predominantly on their concentration in the inoculum of PAB used. © lnra/Elsevier, Paris. Propionibacterium / foIacin / vitamin B12 / plant product quality / pathogen

From Healthy Soil to Healthy Food: An Analysis of the Quality of Food Produced under Contrasting Agricultural Systems

Studies under controlled experimental conditions show a clear advantage for staple food grown under biological/ecological farming conditions as compared to those from conventional farming methods. This is especially true for the vegetative parts of plant products, where lower undesirable (e.g. nitrates) and higher desirable (e.g. vit. C, trace elements) components are present. A better storage quality of plant products (e.g. cabbage, carrots) is also frequently the consequence of biological/ecological farming practices. An overall significantly lower level of residues of agrochemicals has been demonstrated in such products. It is increasingly noticeable, that especially in Central Western Europe, consumers are not exclusively interested in "healthier" food for themselves but also in an healthy environment. This is one of the important reasons, why they are interested in buying food from biological/ecological farming systems and why they are prepared to pay higher prices for such products.

Determination of Plant Phenols by Gel Filtration

ABSTRACTA new method for chromatographic separation and UV spectrophotometric determination of O‐diphenol active principles of plants has been developed. The method is based on a technique of gel filtration on Sephadex LH 20. This technique offers selectivity, resolution, and sensibility; minimum detectable 5 μg/ml. Interactions between the gel and substances examined, which control chromatographic separation, were studied. The method is useful for objectively assessing the quality of plant products and suitable for automation in the case of routine analysis.

The contribution of phenolic substances to quality in plant products

The phenolic constituents of plants are concerned in the quality of plant products, especially in respect of appearance and texture. Many such constituents are concerned in appearance by virtue of their properties as pigments, and many can act as substrates for enzymic browning. Certain phenolic substances are astringent. Lignin is another phenolic constituent which, even in small quantities, markedly increases the toughness of plant cell wall. The chemical nature of the phenolic constituents, and current views as to the pathway of their synthesis in plants, are discussed.