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Introduction. Mexico harbors a great diversity of Spondias purpurea ecotypes, whose fruit is called Mexican plum and has a good consumer acceptance because of its organoleptic and nutritional characteristics. Materials and methods. The concentrations of metabolites in 11 ecotypes of Mexican plum were determined from samples of rind (epicarp) and pulp originating from fresh seasonal fruit. Results and discussion. The mass of these fruits varied from 11.1 to 35.0 g, and the epicarp color ranged from purple and red, to orange and yellow. The content of total soluble solids, total sugars, and vitamin C was of 9.4−18.2 • Brix, 101.0−185.9 mg g −1 fresh weight (FW), and 0.6−2.1 mg g −1 FW, respectively. The total phenolic content was always higher in the epicarp (3.7 mg g −1 FW) than in the pulp (1.3 mg −1 FW), as was the total content of carotenoids and the levels of antioxidant activity. Additionally, positive correlations could be established between antioxidant activity and total phenolics, total phenolics and total carotenoids, and between the antioxidant activity in the epicarp and the total content of vitamin C. In addition, negative correlations were found between hue and the carotenoid content of the pulp, and between hue and the antioxidant activity in the epicarp and pulp. Conclusion. The results suggest that a higher content of phenols, carotenoids, and vitamin C, together with a purple or red coloration of the epicarp, can all be associated with an increase in the antioxidant activities of the epicarp and pulp of the Mexican plum.Keywords: Mexico / Latin America / Mexican plum / Spondias purpurea / antioxidant activity / carotenoids / phenolics / vitamin C / nutritional value Résumé -Attributs de qualité et composés fonctionnels des fruits de divers écotypes de prune mexicaine (Spondias purpurea L.). Introduction. Le Mexique abrite une grande diversité d'écotypes de Spondias purpurea dont le fruit est appelé prune mexicaine et possède une bonne image auprès des consommateurs en raison de ses caractéristiques organoleptiques et nutritionnelles. Matériel et méthodes. Les concentrations en métabolites de 11 écotypes de prune mexicaine ont été déterminées à partir d'échantillons de la peau (épicarpe) et de la pulpe de fruits frais de saison. Résultats et discussion. La masse de ces fruits s'est inscrite entre 11,1 et 35,0 g, et la couleur de l'épicarpe pouvait varier du rouge violacé à l'orange et au jaune. Le contenu en solides solubles totaux, en sucres totaux, et en vitamine C variait de 9,4 à 18,2 • Brix, de 101,0 à 185,9 mg g −1 poids frais (FW), et de 0,6 à 2,1 mg g −1 FW, respectivement. Le contenu phénolique était toujours plus élevé dans l'épicarpe (3,7 mg g −1 FW) que dans la pulpe (1,3 mg g −1 FW), tout comme la teneur en caroténoïdes totaux et les niveaux d'activité anti-oxydante. En outre, des corrélations positives ont pu être établies entre l'activité anti-oxydante et les composés phénoliques totaux, entre les composés phénoliques totaux et les caroténoïdes totaux, et entre l'activité anti-oxyda...

Nitrogen (N) is an essential nutrient for plant growth and development and is especially important in the production of high quality leafy green vegetables. In this experiment, leaf N concentration, chlorophyll concentration (Chl) and weight above fresh matter (AFM) of romaine lettuce (Lactuca sativa L. var. longifolia) were estimated by correlations between in situ SPAD and atLEAF readings. Lettuce was grown in high tunnels during 42 days and was irrigated at five nitrogen levels: 0, 4, 8, 12 and 16 mEq·L-1 of NO3-, based on the Steiner nutrient solution. The N concentration, Chl concentration and AFM were determined in the laboratory, while SPAD and atLEAF readings were measured in situ weekly. SPAD readings had high, positive and significant linear correlations with N (R2 = 0.90), Chl (R2 = 0.97) and AFM (R2 = 0.98); atLEAF readings had a similar linear correlation with N (R2 = 0.91), Chl (R2 = 0.92) and AFM (R2 = 0.97). Besides, SPAD and atLEAF readings had high, positive, and significant linear correlation (R2 = 0.96). Thus, SPAD and atLEAF meters can be used to non-destructively and accurately estimate the N status of lettuce, in a reliable and quick manner during the crop production cycle. In addition, atLEAF is currently more affordable than SPAD.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********