How do plants respond to nutrient shortage by biomass allocation?

Plants constantly sense the changes in their environment; when mineral elements are scarce, they often allocate a greater proportion of their biomass to the root system. This acclimatory response is a consequence of metabolic changes in the shoot and an adjustment of carbohydrate transport to the root. It has long been known that deficiencies of essential macronutrients (nitrogen, phosphorus, potassium and magnesium) result in an accumulation of carbohydrates in leaves and roots, and modify the shoot-to-root biomass ratio. Here, we present an update on the effects of mineral deficiencies on the expression of genes involved in primary metabolism in the shoot, the evidence for increased carbohydrate concentrations and altered biomass allocation between shoot and root, and the consequences of these changes on the growth and morphology of the plant root system.

Matching roots to their environment

Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilisers. ● Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future.

Atributos químicos de um latossolo vermelho sob diferentes sistemas de preparo, adubações e plantas de cobertura

Os sistemas de preparo do solo e tipos de adubações levam à disposição diferenciada dos elementos minerais no perfil do solo, influenciando os seus atributos químicos. O objetivo deste trabalho foi verificar as alterações de alguns atributos químicos de um Latossolo Vermelho de cerrado, sob as adubações orgânica e mineral e plantas de cobertura, estabelecidas nos sistemas de semeadura direta e preparo convencional, sendo cultivado com feijão de inverno e algodão. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdivididas. Nas parcelas foram instalados dois tratamentos (semeadura direta e preparo convencional) e, nas subparcelas, seis (esterco de galinha, esterco de galinha + metade da adubação mineral recomendada, adubação mineral, crotalária, milheto e testemunha). Foram avaliados P, MO, pH, K+, Ca2+, Mg2+, H + Al, Al3+, SB, CTCe e V nas camadas de solo de 0,00-0,10 e 0,10-0,20 m. O uso do adubo orgânico isolado ou associado com adubação mineral contribuiu para os melhores resultados dos atributos químicos do solo avaliados; as plantas de cobertura apresentaram-se semelhantes quanto aos efeitos nas propriedades químicas do solo; e a distribuição dos elementos minerais na camada superficial do solo (0,00-0,20 m) teve comportamento semelhante entre a semeadura direta e o preparo convencional.

Exportação de nutrientes minerais por frutos de aceroleira colhidos em diferentes épocas do ano

A aceroleira produz, no Nordeste brasileiro, de quatro a seis safras por ano e é de se esperar que as exportações de elementos minerais variem em função das diferentes épocas de colheita e das progênies, entre outros fatores. Nesse contexto, este trabalho foi conduzido no Campo Experimental da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Agroindústria Tropical, em Pacajus-CE (4º10' S; 38º27' W), no ano agrícola de 1999/2000, com o objetivo de determinar a exportação de N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn por tonelada de fruta fresca, em diferentes progênies e épocas de colheita. Avaliaram-se os frutos de seis progênies (plantas com 2,5 anos de idade e produção média de 18,16 a 27,62 kg/planta/ano, cultivadas em sistema de sequeiro), em seis épocas de colheita. Adotou-se o delineamento em blocos casualizados, em esquema de parcelas subdivididas no tempo (considerando as progênies como parcelas e as épocas de avaliação as subparcelas), com 4 repetições. Verificou-se que a maior exportação de nutrientes ocorreu nos meses de maior precipitação (fevereiro a abril); as progênies não diferiram entre si quanto à exportação de macronutrientes; as progênies P-52, P- 93 e P-97 exportaram maior quantidade de Cu e Zn; a seqüência de exportação de nutrientes por tonelada de frutos frescos de aceroleira foi: K>N>P>Mg>Ca>S>Fe>Zn>Mn>Cu.

Macronutrients transference by litter production in the Morro do diabo forest (Pontal do Paranapanema region, state of Sao Paulo)

The quantities of macronutrients transfer to soil was estimated by the monthly concentrations of mineral elements in the litter produced, over a period of 2 years in the semideciduous forest of Morro do Diabo (Pontal do Paranapanema), in the State of São Paulo (appr. 22-degrees-31'S, 52-degrees-10'W). The transfer of macronutrients to the soil, through litter, was estimated in 426,95 kg.ha-1.yr-1. Nitrogen was the element with the greatest mobilization, with 183,85 kg.ha-1.yr-1 transferred. The sequence of the quantities of macronutrients transferred was: N > Ca > K > Mg > S > P.

Características fenotípicas de 44 progênies de espinheira-santa (Maytenus ilicifolia Mart. ex Reiss) cultivadas no município de Ponta Grossa, PR

Due to the confirmation of its medicinal properties, the demand and the area planted with 'espinheira-santa' have been increasing. However, there are no sources of propagation material with known characteristics. Progenies of Maytenus ilicifolia Martius ex Reiss (espinheira-santa), originating from Southern Brazil have been analyzed, and currently comprise a germplasm inventory for the species. Studies included the assessment of in natura growth features (height and production of biomass canopy) and plant chemistry (lignin, phenols and mineral element contents), and targeted the creation of a data base, characterizing populations/progenies to be used in future selection and breeding programs of the species. Among the features assessed, were considered desirable the ones related to productivity (high foliar mass to branch mass ratio) and also the absence of thorns on the leaves. High total phenol and tannin content were observed in all the progenies assessed and these features is desirable as long the absence of toxic effects and preservation of the therapeutic quality of the plant medicinal elements produced can be proved.

Filter cake and vinasse as fertilizers contributing to conservation agriculture

Utilising organic residues in agriculture contributes to the conservation of natural resources by recycling carbon and mineral elements. Organic residues produced by the sugar and alcohol agroindustries have great potential for use in conservation agriculture. The production of sugar and alcohol generates large quantities of byproducts, such as filter cake and vinasse, which can be used as soil improvers and substitutes for inorganic phosphorus and potassium fertilizers. However, the use of these residues in agriculture requires specific recommendations for each pedoclimatic condition to prevent environmental damage. © 2013 Renato de Mello Prado et al.

Composição química e atividade antioxidante da polpa e resíduos de abacate 'Hass'

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo da compatibilidade de atemoia ((Annona cherimola Mill. X Annona squamosa L. CV. 'THOMOSON') enxertada em araticum-de-terra-fria [Annona emarginata (Schltdl.) H. Rainer variedade terra-fria] e biribá [[Annona mucosa (Bai.) H. Rainer]

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Agua de reuso e seu efeito sobre parâmetros fisiológicos em manjericão (Ocimum basilicum L.)

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Agua de reuso e seu efeito sobre parâmetros fisiológicos em manjericão (Ocimum basilicum L.)

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Vegetables biofortified with iodine: chemical, agronomic and qualitative aspects of raw and fried potatoes

Iodine is an essential microelement for human health because it is a constituent of the thyroid hormones that regulate growth and development of the organism. Iodine Deficiency Disorders (IDDs) are believed to be one of the commonest preventable human health problems in the world today, according to the World Health Organization: that diseases include endemic goiter, cretinism and fetal abnormalities, among others, and they are caused by lack of iodine in the diet, that is the main source of iodine. Since iodine intake from food is not enough respect to human needs, this can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentration and/or bioavailability of mineral elements in the edible portions of crops through agricultural intervention or genetic selection (biofortification). The introduction of iodized salt is a strategy widely used and accepted to eradicate iodine deficiency, because it is an inexpensive source of stable iodine. Since the intake of salt, though iodized, must still be limited according to the risk of cardiovascular disease, so the increase of iodine content in plants for the production of functional foods is representing a field of study of particular interest and a potential market. In Italy potatoes enriched with iodine are produced by a patented procedure of agronomic biofortification for the fresh market since several years, furthermore they are recently accepted and recommended by Italian Thyroid Association, as an alternative source of iodine. Researches performed during the PhD course intended to characterize this innovative vegetables products, focusing the attention on different aspects, such as chemistry, agriculture, and quality of fresh and fried potatoes. For this purpose, lipid fraction of raw material was firstly investigated, in order to assess whether the presence of iodine in plant metabolism can affect fatty acid or sterol biosynthesis, according to the hypothesis that iodine can be bounded to polyunsaturated fatty acids of cell membranes, protecting them from peroxydation; phytosterols of plant sterol are also studied because their importance in reducing serum cholesterol, especially in potato plant sterols are also involved in synthesis of glycoalkaloid, a family of steroidal toxic secondary metabolites present in plants of the Solanaceae family. To achieve this goal chromatographic analytical techniques were employed to identify and quantify fatty acids and sterols profile of common and iodine enriched row potatoes. Another aim of the project was to evaluate the effects of frying on the quality of iodine-enriched and common potatoes. Since iodine-enriched potatoes are nowadays produced only for the fresh market, preliminary trials of cultivation under controlled environment were carried out to verify if potato varieties suitable for processing were able to absorb and accumulate iodine in the tuber. In a successive phase, these varieties were grown in the field, to evaluate their potential productivity and quality at harvest and after storage. The best potato variety to be destined for processing purposes, was finally subjected to repeated frying cycles; the effects of lipid oxidation on the composition and quality of both potatoes and frying oil bath were evaluated by chromatographic and spectrophotometric analytical techniques. Special attention were paid on volatile compounds of fried potatoes.

Distribution of calcium phosphate in the exoskeleton of larval Exeretonevra angustifrons Hardy (Diptera : Xylophagidae)

Distribution and organisation of the mineral, amorphous calcium phosphate (ACP), has been investigated in the exoskeleton of the xylophagid fly larva Exeretonevra angustifrons Hardy. While head capsule and anal plate are smooth with a thin epicuticle, the epicuticle of the body is thicker and shows unusual micro-architecture comprised of minute hemispherical (dome-shaped) protrusions. Electron microprobe analysis and energy dispersive spectroscopy revealed heterogeneity of mineral elements across body cuticle and a concentration of ACP in the epicuticle, especially associated with the hemispherical structures. Further imaging and analysis showed the bulk of the ACP to be present in nano-sized granules. It is hypothesised that the specific distribution of ACP may enhance cuticular hardness or durability without reducing flexibility. (c) 2004 Elsevier Ltd. All rights reserved.

Maize inbreds from different heterotic groups as favorable sources for increased potential bioavailability of magnesium, iron, manganese and zinc

Malnutrition, as a global problem, is mainly caused by low level of mineral elements in staple food (deficient soil). Biofortification is based on selection of genotypes with enhanced concentration of mineral elements in grain, as well as decreased concentration of substances which interfere bioavailability of mineral elements in gut (like phytic acid), and increased content of substances that increase availability (such as β-carotene). The experiment with 51 maize ( Zea mays L.) inbred lines with different heterotic background was set up in order to evaluate chemical composition of grain and to determine the relations between phytic acid (PA), β-carotene, and mineral elements: Mg, Fe, Mn, and Zn. The highest average phytate, β-carotene, Fe, and Mn content was found in grain of inbreds from Lancaster heterotic group. The highest content of Mg was in grain of Independent source and Zn in grain of BSSS group. Increased level of Fe and Mn in Lancaster lines could be partially affected by higher PA content in grain, while increased β-carotene content could improve Mn and Zn availability from grain of BSSS genotypes and Mg availability from Lancaster inbreds. It is important to underline that PA reduction is followed by Zn content increase in grain of Lancaster heterotic group, as well as that variations in Mg, Fe, and Mn contents are independent on PA status in inbreds from Independent source, indicating that the genotypes with higher Mg, Fe and Mn status from this group could serve as favorable source for improved Mg, Fe, and Mn absorption.

The use of wild fruits of Fragaria vesca L. in preparations with bioactive properties: chemical characterization, antioxidant, antibacterial and antibiofilm activities

Wild strawberry, Fragaria vesca L., belongs to Rosaceae family and is commonly found in roadsides and slopes [1]. The most consumed parts of this plant are its sweet small fruits, which constitute a source of vitamins and phenolic compounds, being also used in infusions due to their organoleptic properties and for the treatment of some intestinal disorders [2, 3]. In the present work, F. vesca fruits were evaluated for their nutritional value and further used in the preparation of infusions. The chemical composition of the fruits and corresponding infusions was determined in terms of soluble sugars, organic acids, tocopherols, folates (by HPLC coupled to different detectors), phenolic compounds (by HPLC-DAD/ESI-MS) and mineral elements (atomic absorption spectroscopy). Some of these bioactive compounds were correlated with antioxidant and antibacterial properties evaluated either in infusions as also in hydromethanolic extracts. Carbohydrates were the main macronutrients in the fruits, followed by fat and proteins. Regarding the fatty acids, polyunsaturated fatty acids showed higher prevalence, mainly due to the presence of D-linolenic (Cl8:3n3) and y-linolenic (Cl8:3n6) acids. Sucrose and citric acid were, respectively, the main sugar and organic acid found in the fruits and in its infusions. The microelement found in higher amounts in both samples was manganese, while potassium and calcium were the macroelements present in higher levels in the fruits and infusions, respectively. Both samples presented folates and tocopherols, being ytocopherol the main isoform detected in the fruits, while a-tocopherol was the only isoform quantified in the infusion. The hydromethanolic extract prepared from the fruits gave higher antioxidant and antibacterial activities, namely against Escherichia coli and Pseudomonas aeruginosa, than the infusion; it also showed capacity to inhibit the formation of bacterial biofilm. Both bioactivities are highly correlated with the presence of phenolic compounds, in which the major are ellagic acid derivatives (sanguiin hlO) followed by tlavan 3-ols ((+)catechin) and anthocyanin compounds (pelargonidin-3-glucoside). Although fruits of wild F. vesca are mainly consumed in fresh, this study also proves the potentiality of their infusions as a source of bioactive molecules and properties.