EFFECT OF THE NUTRIENT SOLUTION ELECTRICAL CONDUCTIVITY (EC) ON THE GROWTH, DEVELOPMENT AND QUALITY OF ENDIVE (CICHORUM ENDIVIA L.) CULTIVATED UNDER COVERS

The influence of nutrient solution adjustment and replacement (management), its electrical conductivity (EC) and plant spacing on yield and quality of strawbeny fruit (var. Torrey) produced in a recirculating hydroponic system was studied at Gosford, New South Wales. Four ways of managing the nutrient solution were examined: (i) pH and EC adjusted daily and the solution replaced every 8 weeks (current grower practice); (ii) as above except that a topping up solution with lower potassium to nitrogen (K: N) ratio was used for EC adjustment; (iii) no daily adjustment of EC or pH and one-third of solution replaced every 2 weeks; and (iv) no daily adjustment of solution volume, EC or pH and full replacement after 8 weeks. Compared with grower practice, these alternative solution management strategies provided no advantage in yield, fruit number, or in the �Brix, citric acid, sweetness or flavour of fruit. Use of a topping up solution supplemented with ammonium nitrate (NH4NO3) and calcium nitrate [Ca(NO3)2] to reduce the K : N ratio from 1.7:1.0 to 1.4:1.0 had no effect (P>0.05) on yield but significantly increased (P<0.05) berry weight and improved fruit aroma. Regardless of which method of nutrient solution adjustment and replacement was used, the chemical composition of the recirculating solution changed markedly over 53 days. The method of nutrient solution management significantly (P<0.05) affected leaf phosphorus (P), calcium (Ca), magnesium (Mg), manganese (Mn), and zinc (Zn) but only Mg fell to a suboptimal level for growth of strawberries. Reducing the EC of the nutrient solution from 3 to 2 dS/m at early fruit set gave heavier (P<0.05) berries compared with constant EC of 2 dS/m. Increasing the EC from 2 to 3 or reducing it from 3 to 2 at early fruit set resulted in sweeter (P<0.05) berries and reducing the EC from 4 to 2 improved fruit aroma. Yield declined (P<0.05) when EC was increased from 2 to 4 dS/m. Solution EC bad significant effects (P<0.05) on leaf P, Mg, Mn and Zn. An increase in planting density from 5.35 to 9.35 plants/m2 lowered (P<0.05) marketable yield per plant and fruit acidity but gave 41% higher (P<0.05) yield on an area basis.

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Silicon attenuates calcium deficiency by increasing ascorbic acid content, growth and quality of cabbage leaves

Scientific Reports ◽

10.1038/s41598-020-80934-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Dalila Lopes da Silva ◽

Renato de Mello Prado ◽

Luis Felipe Lata Tenesaca ◽

José Lucas Farias da Silva ◽

Ben-Hur Mattiuz

Keyword(s):

Ascorbic Acid ◽

Nutrient Solution ◽

Acid Content ◽

Dry Matter ◽

Ascorbic Acid Content ◽

Calcium Deficiency ◽

Ca Deficiency ◽

Leaf Water Loss ◽

Nutrient Solutions

AbstractCalcium (Ca) deficiency in cabbage plants induces oxidative damage, hampering growth and decreasing quality, however, it is hypothesized that silicon (Si) added to the nutrient solution may alleviate crop losses. Therefore, this study aims at evaluating whether silicon supplied in the nutrient solution reduces, in fact, the calcium deficiency effects on cabbage plants. In a greenhouse, cabbage plants were grown using nutrient solutions with Ca sufficiency and Ca deficiency (5 mM) without and with added silicon (2.5 mM), arranged as a 2 × 2 factorial in randomized blocks, with five replications. At 91 days after transplanting, the plants were harvested for biological evaluations. In the treatment without added Si, Ca deficiency promoted oxidative stress, low antioxidant content, decreased dry matter, and lower quality leaf. On the other hand, added Si attenuated Ca deficiency in cabbage by decreasing cell extravasation while increasing both ascorbic acid content and fresh and dry matter, providing firmer leaves due to diminished leaf water loss after harvesting. We highlighted the agronomic importance of Si added to the nutrient solution, especially in crops at risk of Ca deficiency.

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Performance of Hydroponically Cultivated Geranium and Common Verbena under Salinity and High Electrical Conductivity Levels

Agronomy ◽

10.3390/agronomy11061237 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1237

Author(s):

Antonios Chrysargyris ◽

Spyridon A. Petropoulos ◽

Dejan Prvulovic ◽

Nikolaos Tzortzakis

Keyword(s):

Electrical Conductivity ◽

Chlorophyll Fluorescence ◽

Nutrient Solution ◽

High Salinity ◽

Stomatal Resistance ◽

Water Sources ◽

Total Flavonoid ◽

Control Treatment ◽

Total Phenolic ◽

High Electrical Conductivity

Abiotic factors in nutrient solutions (NSs), such as salinity and high electrical conductivity (EC), may adversely alter plant growth and crop performance. However, there are medicinal/aromatic plants which can not only withstand these adverse conditions, but which can also increase their productivity or even enhance their quality in such conditions. As fresh water sources suitable for irrigation are becoming more and more limited, the use of low-quality water sources and hydroponic growing systems have been suggested as the main alternatives. Towards that direction, this study aims to evaluate the effect of high EC levels in NSs on geranium (Pelargonium graveolens L’Hér.) and common verbena (Verbena officinallis L.) plants cultivated in a soilless (perlite) hydroponics system. Plants were irrigated with a full nutrient solution of EC 2.1 dS m−1 and pH 5.8 until they reached a uniform size. Then, three treatments were applied, namely: (a) a control treatment with an EC of 2.1 dS m−1 in the NS, (b) a high-salinity NS created by adding 75 mM of NaCl (EC under 8.5 dS m−1) and (c) a concentrated NS with an EC of 8.5 dS m−1. In pelargonium, high salinity decreased the total phenolic and total flavonoid contents; antioxidant capacity; N, K, Mg and P content; as well as chlorophyll fluorescence, compared to the control treatment. On the other hand, increased salinity levels increased the Na and Ca content and stomatal resistance. In common verbena, salinity decreased total phenolic content and chlorophyll fluorescence but increased total flavonoid content; antioxidants; leaf K, P, Na, Cu and Zn content; and stomatal resistance, compared to the control. In both species, high EC did not affect polyphenols, flavonoids or antioxidants, whereas it increased stomatal resistance and nutrient accumulation in the leaves, and decreased chlorophyll fluorescence compared to the control treatment. Damage indices, indicated by lipid peroxidation, hydrogen peroxide production and the elevation of enzymes’ antioxidant activities, were evidenced in both saline- and high-EC-treated plants. In conclusion, despite having the same EC levels in the nutrient solution, it seems that ionic stress caused by high mineral concentrations in the nutrient solution had less severe effects on the tested plants than the relevant osmotic stress caused by high salinity due to the addition of NaCl in the nutrient solution.

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DIET QUALITY OF MOROCCAN ADOLESCENTS LIVING IN MOROCCO AND IN SPAIN

Journal of Biosocial Science ◽

10.1017/s0021932016000183 ◽

2016 ◽

Vol 49 (2) ◽

pp. 173-186 ◽

Cited By ~ 3

Author(s):

M. Del Pilar Montero ◽

Ana Isabel Mora-Urda ◽

Karim Anzid ◽

Mohamed Cherkaoui ◽

M. Dolores Marrodan

Keyword(s):

Diet Quality ◽

Eating Habits ◽

Meat Consumption ◽

Negative Consequences ◽

The North ◽

Socioeconomic Changes ◽

Cholesterol Intake ◽

Growth Development ◽

And Migration

SummaryIntra-population socioeconomic changes and migration are powerful factors in changing eating habits. Changes in eating habits could affect the nutritional status, growth, development and health of adolescents. The aim of this study was to compare the diet of adolescents of Moroccan origin living in Spain with that of adolescents living in Morocco. The sample comprised 428 Moroccan adolescents aged from 12 to 19 recruited in high schools: 327 living in Ouarzazate (Morocco) and 101 living in Madrid (Spain). The variables studied were energy intake (kcal/day), diet quality indicators (adherence to the Mediterranean Adequacy Index (MAI); cholesterol intake (mg/day); fibre intake (g/day) and energy profile)); and indicators of keeping traditional customs (halalmeat consumption, bread made at home). Teenagers from Morocco living in Madrid consumed more calories, proteins, saturated fats and simple sugars (p<0.001) than those living in Morocco. Their diet was of lower quality than that of their peers in Morocco. This difference was more marked in boys than in girls. Changes in eating habits associated with migration from the south to the north Mediterranean basin can benefit young migrants in an immediate way (through greater availability of energy and nutrients), but later in life it could have negative consequences for their health, increasing the risk of overweight, obesity and cardiovascular and metabolic problems.

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