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- Variation of carbon and isotope natural abundances (δ15N and δ13C) of whole-plant sweet potato (Ipomoea batatas L.) subjected to prolonged water stressPublication . Gouveia, Carla S.S.; Ganança, José F.T.; Slaski, Jan; Lebot, Vincent; Carvalho, Miguel Â. A.Sweet potato (Ipomoea batatas L.) is an important crop in the world, cultivated in temperate climates under low inputs. Drought changes the plant biomass allocation, together with the carbon and nitrogen isotopic composition (δ13C and δ15N), whose changes are faintly known in sweet potato crops. Here, we show the biomass allocation of eight sweet potato accessions submitted to drought during 3 months, using the δ13C, δ15N, carbon isotope discrimination (Δ13C), total carbon (TC) and water use efficiency (WUE) traits. The tolerant accessions had improved WUE, with higher TPB and TC. Storage roots and shoots had a heavier δ13C content under drought stress, with greater 13C fixation in roots. The Δ13C did not show a significant association with WUE. The δ15N values indicated a generalised N reallocation between whole-plant organs under drought, as a physiological integrator of response to environmental stress. This information can aid the selection of traits to be used in sweet potato breeding programs, to adapt this crop to climate change.
- Review of sewage sludge as a soil amendment in relation to current international guidelines: a heavy metal perspectivePublication . Nunes, Nuno; Ragonezi, Carla; Gouveia, Carla S. S.; Carvalho, Miguel Â. A. Pinheiro deOverexploitation of resources makes the reutilization of waste a focal topic of modern society, and the question of the kind of wastes that can be used is continuously raised. Sewage sludge (SS) is derived from the wastewater treatment plants, considered important underused biomass, and can be used as a biofertilizer when properly stabilized due to the high content of inorganic matter, nitrate, and phosphorus. However, a wide range of pollutants can be present in these biosolids, limiting or prohibiting their use as biofertilizer, depending on the type and origin of industrial waste and household products. Long-term applications of these biosolids could substantially increase the concentration of contaminants, causing detrimental effects on the environment and induce hyper accumulation or phytotoxicity in the produced crops. In this work, some critical parameters for soils and SS agronomic use, such as organic matter, nitrogen, phosphorous, and potassium (NPK), and heavy metals concentration have been reviewed. Several cases of food crop production and the accumulation of heavy metals after SS application are also discussed. SS production, usage, and legis lation in EU are assessed to determine the possibility of sustainable management of this bioresource. Additionally, the World Health Organization (WHO) and Food and Agriculture Organization (FAO) guidelines are addressed. The opportunity to produce bioenergy crops, employing sewage sludge to enhance degraded land, is also considered, due to energy security. Although there are numerous advantages of sewage sludge, proper screening for heavy metals in all the variants (biosolids, soil, food products) is a must. SS application requires appropriate strict guidelines with appropriate regulatory oversight to control contamination of agricultural soils.
- Abscisic acid phytohormone estimation in tubers and shoots of Ipomoea batatas subjected to long drought stress using competitive immunological assayPublication . Gouveia, Carla S. S.; Ganança, José F. T.; Slaski, Jan J.; Lebot, Vincent; Carvalho, Miguel Â. A. Pinheiro deSweet potato (Ipomoea batatas L.), typically cultivated in temperate climates under low inputs, is one of the most important crops worldwide. Abscisic acid (ABA) is an important plant stress-induced phytohormone. Hitherto, few works analyzed the ABA function in sweet potato tissue growth. Very scarce information is available concerning the ABA role in sweet potato response to water scarcity conditions. Here, we show the ABA content var iation in shoots and tubers of eight sweet potato accessions subjected to drought stress. ABA was also related to other resistance traits, such as chlo rophyll content index (CCI), carbon isotopic discrimination (Δ13C), oxalic acid (OA) and water use efficiency (WUE), to assess stress response mecha nisms to water deficit between their organs. The most resilient drought stressed sweet potato plants accumulated ABA-shoot, and significantly decreased the ABA-tuber content. ABA signaling was related to Δ13C and CCI decrease and WUE increment, as an attempt to cope with water stress by partially closing the stomata. The partial closure of stomata could be in part due to the presence of OA-shoots, known to affect the intensity of the ABA-shoot signal in stomatal closure. Higher CCI content and minimal Δ13C-shoot differences indicated good carboxylation fractionation, with higher Δ13C-tuber content as an indicator of efficient tuber 13C fixation and growth. Our work demonstrated that ABA could be used in conjunction with the other traits studied for the assessment of sweet potato whole-plant responses to environmental stresses, and thus aid the selection of the best drought tolerant genotypes for breeding programs.
- Screening for drought tolerance in thirty three Taro cultivarsPublication . Ganança, José F. T.; Freitas, José G. R.; Nóbrega, Humberto G.M.; Rodrigues, Vanessa; Antunes, Gonçalo; Gouveia, Carla S. S.; Rodrigues, Miguel; Chair, Hana; Carvalho, Miguel A. A. Pinheiro de; Lebot, VincentTaro [Colocasia esculenta (L.) Schott] is a root crop which is an important staple food in many regions of the world, producing 10.5 million tonnes on 1.4 million hectares a year. The crop is cultivated in wet (rain fed) or irrigated conditions, requiring on average 2,500 mm water per year, and in many countries it is cultivated in flooded plots. It is estimated that taro production could decrease by 40% as a result of the increase in drought and other severe events. In this work, thirty three accessions, including local cultivars, selected and hybrid lines were submitted to long duration drought stress and screened for tolerance. Twelve physiological, morphological and agronomic traits were measured at harvest, and subject to multivariate analysis. Stress indices, Water Use Efficiency and Factorial Analysis were useful for discriminating accessions regarding drought tolerance and yield stability, and drought tolerant and susceptible cultivars were identified. Our results confirm that different taro cultivars have different drought avoidance and tolerance strategies to cope with water scarcity. Better yield performers minimised biomass and canopy loss, while tolerance was observed in cultivars that presented low potential yield, but efficiently transferred resources to enhance corm formation. Among the 33 accessions, two local cultivars showed high yield stability and could be considered as suitable parents for breeding programs, while two others are well adapted to drought, but with overall low yield potential.
- Phenotyping the ideotypes of two maize landraces from Madeira archipelago using morpho-agronomic traits and zein patternPublication . Carvalho, Miguel Â. A. Pinheiro de; Sardinha, Carmen M. S.; Gouveia, Carla S.S.; Silva, Emanuel M. da; Nóbrega, Humberto G. M.; Ganança, José F. T.; Nóbrega, Sónia R.; Santos, Teresa M. M. dosMadeira Archipelago holds specific maize genetic resources whose populations, representing field diversity, were previously classified into four main landrace groups. The ISOPs 0061 and 0070, with common names of “Milho Sequeiro” and “Milho Branco” yellow and white maize, respectively, represent the ideotypes of two of these landraces. These ideotypes have now been analyzed using morpho-agronomic and biochemical traits, to phenotype these landraces. The variation of nine of the ten morpho-agronomic traits was used to separate the landraces ideotypes. However, the seven traits of seed biochemical composition did not allow to segregate the landraces ideotypes. This is not the case of zein pattern, which polymorphism shows to be specific for each ideotype. The original ideotypes populations were regenerated twice under low input conditions. Zein patterns of the original and regenerated accessions were compared, using two electrophoresis techniques. The lab-on-a-chip electrophoresis showed that the standard SDS-PAGE zein pattern with six fractions could be separated into eighteen (ISOP 0061) and twenty (ISOP 0070) protein bands. In contrast, no significant changes were detected in the zein pattern structure of the initial and regenerated accessions of both landraces ideotypes. The chip electrophoresis showed to be a suitable technique to screen and characterize a large number of individuals and accessions of the germplasm collections, due to its reproducibility. In particular, the zein patterns can be used to phenotype ideotypes and establish a formula representing their structure, allowing to detect changes in landrace structure, occurring as a result of gene bank management actions.
- Drought avoidance and phenotypic flexibility of sweet potato (Ipomoea batatas (L.) Lam.) under water scarcity conditionsPublication . Gouveia, Carla S. S.; Ganança, José F. T.; Nóbrega, Humberto G. M.; Freitas, José G. R.; Lebot, Vincent; Carvalho, Miguel Â. A. Pinheiro deSweet potato (Ipomoea batatas (L.) Lam.) is an important staple food in several regions of the world. Water scarcity is the most devastating abiotic stress, with a great impact on crop productivity, food security, and subsistence. Drought restricts the nutrient intake and transport into the plant. Tolerant crops have morphological mechanisms of drought avoidance and/or phenotypic flexibility, showing also good water and nutrient efficiency. However, that information is scarce for sweet potato, which is usually based on physiological traits of plant productivity. Here, we show the physiological responses of eight sweet potato accessions subjected to a 3 months’ drought period, by recording their differences for nutrient and leaf chlorophyll content, biomass and stress level. Our results showed that the differences in water use efficiency (WUE, +68.1%), chlorophyll content index (CCI, -5.3%), total plant biomass (TPB, -55.4%), nutrient efficiency (NER, +38.1%) and nutrient harvest index (NHI, +2.9%) where significantly correlated with the water regime. The water shortage led to a drought avoidance response, with TPB loss in all accessions. Distinct phenotypic flexibility responses were also recorded and explained by the root:shoot ratio (R:S) and stress index (SI) variation of the storage root and shoot growth. This information could be relevant for the development of sweet potato breeding programs, adapting this crop to climate change.
- Ecology and diversity of Solanum trisectum Dunal from Madeira Island: implications for Its conservationPublication . Alves, Sónia Ferraz; Reis, Fábio; Henriques, Dina; Freitas, Gregório; Gouveia, Carla S.S.; Fernandes, Francisco Manuel; Carvalho, Miguel A. A. Pinheiro deSolanum trisectum Dunal is an endemic Solanaceae of Madeira Island (Portugal), considered critically endangered due to its extreme rarity. Since its discovery this species has shown a narrow distributional range mainly on the northern side of the island, with scattered and small populations and large time gaps between sightings. The present work aimed to understand the underlying ecological underpinnings for this species rarity towards an effort to increase the success of conservation actions. Data on historical locations, environmental conditions field surveys, reinforcement in situ and ex situ germination trials were obtained. The species was found to currently occur only in two wild populations and two reinforcement sites, amounting to twenty-four plants in total. Statistical analysis of these data related wild populations and successful reinforcement sites, separating them from other sites where the reinforcement did not succeed. This suggests that the successful reinforcement sites showed conditions more similar to wild population sites compared to non-successful ones. The data obtained supports the hypothesis that S. trisectum distribution and rarity is determined by species specific habitat needs, i.e., abiotic conditions, which have been for the first time assessed during the present work. Further, this study also reinforces the classification of S. trisectum as a top priority species for conservation.
- Nutritional and mineral variability in 52 accessions of common bean varieties (Phaseolus vulgaris L.) from Madeira IslandPublication . Gouveia, Carla S.S.; Freitas, Gregório; Brito, José H. de; Slaski, Jan J.; Carvalho, Miguel Â. A. Pinheiro deThe Phaseolus vulgaris L. is one of the traditional and most important leguminous crops in the Island of Madeira. The island’s bioclimatic tiers, agro-ecological environment and traditional farming practices had a great influence on the evolution of regional bean landraces. The variabili ty of the nutritional and mineral seeds composition of 59 accessions of the Madeiran landraces, standard and commercial varieties was evaluated. Wide ranges of variability in biochemical pa rameters were reported among the Madeiran landraces, being the best sources of protein and mineral nutrition, according to the statistical results and literature comparative evaluation. Spe cifically, the content (g per 100 g DW) of ash ranged from 3.64 - 5.67, lipids from 0.57 - 2.86, pro tein from 18.55 - 29.69, starch from 23.40 - 52.65, soluble sugars from 2.97 - 6.84, while content of dry matter was from 83.35 - 93.55. The seeds also contained (per 100 g DW) between 2.55 - 4.83 g N, 0.30 - 7.50 g P, 1.30 - 2.49 g K, 0.10 - 0.18 g Mg, 4.10 - 10.00 mg Fe, 50.0 - 1.40 mg Cu, 2.20 - 5.00 mg Zn, 0.90 - 3.80 µg Mn and 0.20 - 2.40 µg B. This variability implies that the screened germplasm could serve as a source for breeding new varieties with improved biochemical and nutritional traits or could be highly recommended to meet specific dietary requirements. The cultivar Vagin ha Grossa (ISOP 713) revealed low carbohydrate content that could be a good food choice for di abetics, while cultivar Vermelho (ISOP 724) bean should be offered as a valuable alternative source of protein and minerals in the local diet.
- Avaliação de recursos genéticos agrícolas: análise nutricional e anti-nutricional de variedades regionais de feijão (Phaseolus vulgaris L.)Publication . Gouveia, Carla Susana Silva; Carvalho, Miguel Ângelo Almeida Pinheiro deO presente trabalho teve como objectivo proceder à avaliação da qualidade nutricional de 20 variedades regionais de Phaseolus vulgaris L. e à análise comparativa dos parâmetros bioquímicos (nutricionais e anti-nutricionais) obtidos recorrendo às técnicas analíticas convencionais por química molhada e de NIRS (Near Infra-Red Spectroscopy). Uma tipificação das variedades regionais de feijão foi realizada recorrendo a sete parâmetros ou caracteres (traits) nutricionais compreendidos em humidade, proteína bruta, lípidos totais, açúcares solúveis, amido, cinzas e minerais. A faseolamina foi incluída na tipificação do feijão como parâmetro anti-nutricional enquanto inibidor de enzimas digestivas. A variedade que apresentou uma melhor qualidade nutricional foi o feijão vermelho (ISOP 00724), enquanto que o feijão Filipe (ISOP 00478) apresentou uma maior actividade inibitória da PPA (amilase do pâncreas suíno), contribuindo de igual forma como uma característica de qualidade deste feijão. A aplicação de técnicas de quimiometria na quantificação dos vários parâmetros de qualidade nutricional, através da técnica de NIRS, permitiu o desenvolvimento dos modelos PLS globais após a colecção dos valores de referência e obtenção dos respectivos espectros de cada ISOP em análise. A análise comparativa dos parâmetros nutricionais, recorrendo às técnicas analíticas convencionais por química molhada e de NIRS, permitiu relacionar os parâmetros cinzas e proteína bruta como os principais critérios nutricionais para distinção das variedades regionais quanto à sua qualidade, ao diferirem significativamente relativamente aos parâmetros restantes. A partir destas duas técnicas, conclui-se que a espectroscopia NIR associada a técnicas de análise multivariada consegue quantificar os parâmetros em estudo, permitindo distinguir amostras das variedades regionais, quanto às suas características nutricionais, exigindo uma preparação reduzida da amostra, com consequente custo de análise muito reduzido. Este trabalho representou o início de uma base de fenotipagem a partir de caracteres nutricionais, estabelecendo-se um perfil das variedades regionais de feijão e avaliação da importância dos caracteres na sua distinção e tipagem.
- Study of drought tolerance responses in root and tuber crops using NIRS technology and biochemical markers model assessmentPublication . Gouveia, Carla Susana Silva; Carvalho, Miguel Ângelo Almeida Pinheiro de; Lebot, VincentBatata-doce (Ipomoea batatas L.) e inhame (Colocasia esculenta L.) representam a segunda fonte alimentar mais importante do mundo. Atualmente, as alterações climáticas ameaçam a produtividade agrícola, principalmente devido à escassez de água, cujo efeito não é ainda suficientemente compreendido. As principais lacunas são a perceção do efeito da seca, através da eficiência no uso da água (WUE), bases bioquímicas e fisiológicas de produtividade e qualidade. Aqui, apresentamos os modelos das respostas de sete acessos de inhame e oito de batata-doce às condições de insuficiência hídrica, seguindo-se a avaliação da tolerância à seca, através da criação de modelos de previsão rápidos e precisos baseados na espectroscopia próxima do infravermelho (NIRS). Os resultados forneceram informações relevantes sobre o desenvolvimento destas culturas em ambiente de stress. A escassez de água conduziu a mecanismos de redução da perda de água, com diminuição da biomassa total (TPB) em todos os acessos. Respostas distintas na flexibilidade fenotípica foram explicadas pela razão parte tuberosa/parte vegetativa e variação do índice de stress no crescimento dos órgãos. Acessos com resposta mais favorável à seca melhoraram a WUE, com menor redução de TPB. Os parâmetros de composição isotópica de carbono (δ13C) e azoto (δ15N) atuaram como integradores fisiológicos de resposta ao stress ambiental. Maior teor de δ13C representou maior fixação de carbono, e maior variação de δ15N indicou realocação generalizada de azoto entre os órgãos sob stress. O teor de oxalatos relacionou-se significativamente com o amido, índice de clorofila e proteína. O desenvolvimento da técnica NIRS demonstrou ser uma excelente ferramenta para detetar as respostas destas culturas à seca, através de parâmetros de qualidade e fisiológicos, que poderá ser aplicada na investigação, pelos agricultores e empresas. Esta informação também auxiliará na seleção de características a serem utilizadas nos programas de melhoramento de inhame e batata-doce, para adaptação às mudanças climáticas.