Marcelle Michelotti Bettoni

Durum wheat quality traits affected by mycorrhizal inoculation, water availability and atmospheric CO2 concentration

Abstract. Predicted reduced precipitation, enhanced evaporative demand and increasing CO2 in the atmosphere will strongly influence wheat production. The association of wheat with arbuscular mycorrhizal fungi (AMF) improves growth under stressful conditions. Our objective was to test the influence of mycorrhizal inoculation on yield, and accumulation of macro- and micro-nutrients and gliadins in grains of durum wheat (Triticum durum Desf.) plants grown under different CO2 concentrations and water regimes. The main factors of the experimental design were mycorrhizal inoculation (inoculated or non-inoculated plants); atmospheric CO2 concentration (ambient, ACO2, or elevated, ECO2); and water regime (optimal or restricted water regime). At ACO2, the simultaneous application of AMF and water deficit decreased the number of seeds per spike without affecting the biomass of grains, and grains accumulated higher contents of copper, iron, manganese, zinc and gliadins. The opposite effect was observed with ECO2 where, regardless of mycorrhizal and water treatment factors, a general depletion of contents of micro- and macro-nutrients and gliadins was detected. Whereas mycorrhizal inoculation together with drought applied to plants cultivated at ACO2 improved wheat grain quality parameters, under ECO2, mycorrhization did not ameliorate grain quality parameters detected in plants that produced the largest grain dry matter values.

The interaction between mycorrhizal inoculation, humic acids supply and elevated atmospheric CO 2 increases energetic and antioxidant properties and sweetness of yellow onion

The combined application of humic substances and mycorrhizal inocula under increased CO2 in the air is a promising horticultural technique for improving the quality of greenhouse-grown onion seedlings. The objective of this study was to evaluate if the development and qualitative characteristics of bulbs from the yellow onion Allium cepa L. Alfa São Francisco improved with the application of the abovementioned agronomic, biotic, and environmental factors. The lowest dry matter was achieved in bulbs of onions not inoculated with mycorrhizal fungi, non-amended with humic acids (HA), and grown at ambient CO2. Mycorrhizal inoculation significantly increased bulb biomass in plants cultivated at ambient CO2, and not fertilized with HA, which may be a consequence of the enhanced acid phosphatase activity in roots. The application of HA always increased bulb dry matter, which were more evident at elevated rather than ambient CO2 conditions and correlated with improved acid phosphatase activity in the plants at elevated CO2. Mycorrhizal inoculation, HA supplementation, and elevated CO2 in the air had an additive effect of increasing the content of soluble sugars, proteins, and phenolics in bulbs. While high levels of sugars and proteins enhanced the energetic value of onions, the increase in phenolics improved their antioxidant properties. The triple interaction between mycorrhization, HA fertilization, and elevated CO2 also increased the ratio between soluble solids and total titratable acidity, which may enhance the perception of sweetness and make onions more pleasant for consumption.

Teores de clorofila em cultivares de tomateiro submetidas a aplicações foliares de magnésio

Although the foliar nutrients application is well disseminated in horticulture, the technology is still controversial, since the products efficiency is related to the characteristics of the formulations, especially the sources of nutrients used. Thus, this study aimed at identifying changes in chlorophyll contents, by using the colorimetric method and a chlorophyll meter, as well as in the Mg content in tomato plant leaves, as related to foliar applications of solutions containing Mg (OH) 2 or MgCl 2 . Two tomato cultivars were subjected to fertigation with low Mg addition. The data from the chlorophyll meter were corroborated by the colorimetric method, indicating that the solutions containing 1.0 mL L -1 and 2.0 mL L -1 of a suspension concentrate (300 g L - 1 of Mg, as Mg(OH) 2 ) and the solution containing 3.75 mL L - 1 of MgCl 2 were effective in increasing the chlorophyll contents, resulting in the Mg absorption and metabolization. The solution containing 7.5 mL L - 1 of MgCl 2 caused fitotoxicity and reduced the chlorophyll contents, although promoting a higher Mg content in leaves.