RESUMEN

In vivo and micro chemical analytical methods have the potential to improve our understanding of plant metabolism and development. Benchtop microprobe X-ray fluorescence spectroscopy (µ-XRF) presents a huge potential for facing this challenge. Excitation beams of 30 µm and 1 mm in diameter were employed to address questions in seed technology, phytopathology, plant physiology, and bioremediation. Different elements were analyzed in several situations of agronomic interest: (i) Examples of µ-XRF yielding quantitative maps that reveal the spatial distribution of zinc in common beans (Phaseolus vulgaris) primed seeds. (ii) Chemical images daily recorded at a soybean leaf (Glycine max) infected by anthracnose showed that phosphorus, sulfur, and calcium trended to concentrate in the disease spot. (iii) In vivo measurements at the stem of P. vulgaris showed that under root exposure, manganese is absorbed and transported nearly 10-fold faster than iron. (iv) Quantitative maps showed that the lead distribution in a leaf of Eucalyptus hybrid was not homogenous, this element accumulated mainly in the leaf border and midrib, the lead hotspots reached up to 13,400 mg lead kg-1 fresh tissue weight. These case studies highlight the ability of µ-XRF in performing qualitative and quantitative elemental analysis of fresh and living plant tissues. Thus, it can probe dynamic biological phenomena non-destructively and in real time.

RESUMEN

The fruit quality of 6 citrus cultivars growing in the same orchard was determined at ripening stage in both 2014 and 2015. We further measured the components of sugar (sucrose, fructose and glucose), organic acid (citric, malate and quinic acid), enzymes related to Glycolysis and Krebs cycle and mineral elements at 5 stages of fruit development in the second year. The results showed that at ripening stage of both years, 'Newhall' cultivar had higher TSS concentration and the TSS/TA ratio but lower TA concentration, while 'Flame' cultivar was exactly opposite. Sucrose and citric acid were the most accumulated compounds in fruit during the fruit development of 6 citrus cultivars. Fruit sucrose concentration increased from 9.26 mg·kg-1 at 60 DAFB to 50.92 mg·kg-1 at 180 DAFB, and the citric acid concentration increased from 1.41 mg·kg-1 at 60 DAFB to 29.87 mg·kg-1 at 90 DAFB or 29.02 mg·kg-1 at 120 DAFB then decreased till ripening (5.47 mg·kg-1). We found ACO was the key enzyme resulting in the difference of citric acid accumulation, but not quite clear in sucrose metabolism. The fruit mineral nutrient concentrations of 6 cultivars during the fruit development were 0.94-1.92% of N, 0.11-0.23% of P, 1.03-1.37% of K, 0.31-1.15% of Ca, 0.11-0.29% of Mg, 3.97-72.34 mg·Fe kg-1, 1.93-10.64 mg·Mn kg-1, 1.56-10.73 mg·Cu kg-1, and 0.90-16.80 mg·Zn kg-1. We also analyzed the relationship among each sugar, organic acid component and mineral nutrient in this study by curve estimation and PCA analysis. The results indicated that only Mg was significantly correlated with both sugar and organic acid component, negative and positive respectively. It suggested that the accumulation of sugar and organic acid might be related to the dynamic changes of fruit Mg concentrations of 6 citrus cultivars.

Asunto(s)

Ácidos Carboxílicos/análisis , Citrus/metabolismo , Magnesio/análisis , Azúcares/metabolismo , Cromatografía de Gases , Ácido Cítrico/análisis , Citrus/química , Citrus/crecimiento & desarrollo , Fructosa/metabolismo , Frutas/química , Frutas/metabolismo , Glucosa/metabolismo , Malatos/análisis , Ácido Quínico/análisis , Sacarosa/metabolismo

RESUMEN

Pfaffia glomerata (Spreng.) Pedersen, known as brazilian ginseng, is an extensively used plant in folk medicine due to its phytotherapic characteristics. This work aimed to determine the best combination of sucrose (30, 45 and 60 g L-1) and nitrogen (50, 75, 100 and 125% of the strength of MS medium) on micropropagation of P. glomerata. In 30 days of cultivation, sucrose ranging from 40 to 45g L-1 and nitrogen at 50% increased the height and the number of nodes. The number of shoots was greater at concentration of 55g L-1 sucrose combined with 70% N. The dry matter of roots, aerial parts, and of the whole seedling was increased on 50% N and 45g L-1 sucrose. Altogether the halved concentration of nitrogen and the increased concentration of sucrose to 45g L-1 increase the height, the number of nodes and the shoots as well as biomass production improved due to an enhancemednt of carbon use.

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Pfaffia glomerata (Spreng.) Pedersen, conhecida como ginseng brasileiro, é uma planta extensivamente usada na medicina popular em decorrência de possuir propriedades fitoterápicas. Este trabalho teve como objetivo determinar a melhor combinação de concentração da sacarose (30, 45 e 60g L-1) e do nitrogênio (50, 75, 100 e 125% da concentração padrão do meio MS) para a multiplicação in vitro de P. glomerata. Aos 30 dias de cultivo, verificou-se que concentrações entre 40 e 45g L-1 de sacarose e 50% de N propiciaram maior crescimento em altura e número de segmentos nodais por plântula. O número de brotações foi maior na concentração de 55g L-1 de sacarose combinada com 70% de N. A matéria seca de raízes, da parte aérea e do total da plântula foi maior na concentração de 45g L-1 de sacarose associada com 50% de N. No geral, a redução da concentração de N para 50% daquela padrão do meio MS, associada a um incremento na dose de sacarose para 45g L-1, favorece o crescimento em altura, número de segmentos nodais e brotações, bem como a produção de biomassa de P. glomerata cultivada in vitro, devido ao estímulo ao uso do carbono.

RESUMEN

Pfaffia glomerata (Spreng.) Pedersen, known as brazilian ginseng, is an extensively used plant in folk medicine due to its phytotherapic characteristics. This work aimed to determine the best combination of sucrose (30, 45 and 60 g L-1) and nitrogen (50, 75, 100 and 125% of the strength of MS medium) on micropropagation of P. glomerata. In 30 days of cultivation, sucrose ranging from 40 to 45g L-1 and nitrogen at 50% increased the height and the number of nodes. The number of shoots was greater at concentration of 55g L-1 sucrose combined with 70% N. The dry matter of roots, aerial parts, and of the whole seedling was increased on 50% N and 45g L-1 sucrose. Altogether the halved concentration of nitrogen and the increased concentration of sucrose to 45g L-1 increase the height, the number of nodes and the shoots as well as biomass production improved due to an enhancemednt of carbon use.

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Pfaffia glomerata (Spreng.) Pedersen, conhecida como ginseng brasileiro, é uma planta extensivamente usada na medicina popular em decorrência de possuir propriedades fitoterápicas. Este trabalho teve como objetivo determinar a melhor combinação de concentração da sacarose (30, 45 e 60g L-1) e do nitrogênio (50, 75, 100 e 125% da concentração padrão do meio MS) para a multiplicação in vitro de P. glomerata. Aos 30 dias de cultivo, verificou-se que concentrações entre 40 e 45g L-1 de sacarose e 50% de N propiciaram maior crescimento em altura e número de segmentos nodais por plântula. O número de brotações foi maior na concentração de 55g L-1 de sacarose combinada com 70% de N. A matéria seca de raízes, da parte aérea e do total da plântula foi maior na concentração de 45g L-1 de sacarose associada com 50% de N. No geral, a redução da concentração de N para 50% daquela padrão do meio MS, associada a um incremento na dose de sacarose para 45g L-1, favorece o crescimento em altura, número de segmentos nodais e brotações, bem como a produção de biomassa de P. glomerata cultivada in vitro, devido ao estímulo ao uso do carbono.

RESUMEN

• Here, we investigated the spatial and temporal abundance of mycelial mats in a tropical rain forest to determine their effects on the concentration of mineral nutrients in soils and fine roots. • Mats were marked and followed over three seasons. Fine-root mass and the concentration of mineral nutrients in both soils and roots were determined for mat-associated soils and for a control group. • Mats were more abundant in the dry season than in the wet season. The concentration of mineral nutrients in soils and fine roots increased from the rainy season to the end of the dry season. Mats appeared to affect the concentration of phosphorus, potassium and calcium, and the carbon : nitrogen and nitrogen : phosphorus ratios in soils and roots during all seasons. • Mats appeared to compete with plants for certain minerals. This could be part of 'bottom up' effects that may influence underground herbivory, as well as the above-ground concentrations of mineral nutrients in plants. Mats are relevant to understanding soil biodiversity and the potential feedback paths between the soil and above-ground subsystems.