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In Mexico, the young cladodes (nopalitos) and floral buds (tunitas) of Nopalea cochenillifera are consumed as vegetables, but there is no information on the content of structural polysaccharides and dietary fiber in floral buds. The objective of this study was to extract, purify and quantify the structural polysaccharides (mucilages, pectins, loosely and tightly hemicelluloses bound to cellulose, and cellulose) and dietary fiber (soluble, insoluble and total) in floral buds of N. cochenillifera in four stages of development. The hypothesis was that soluble structural polysaccharides increase during the development of floral buds. Floral buds were harvested between 06:00 and 09:00 h in the municipality of San Ciro de Acosta, San Luis Potosí, Mexico; they were classified by their length and development in four stages (GS); thorns were eliminated, lyophilized and crushed. The structural polysaccharides were extracted in sequence with aqueous solvents (water, ammonium oxalate and potassium hydroxide). Soluble dietary fiber was determined as the sum of mucilage, pectin and loosely bound hemicelluloses, and insoluble as the sum of tightly bound hemicelluloses and cellulose. Total dietary fiber was the sum of all structural polysaccharides. The experimental design was completely randomized with four replications per treatment. The content of mucilage and loosely bound hemicelluloses varied between GS, from 5.6 to 9.8 % and from 3.1 to 15.0 %. Pectins, tightly bound hemicelluloses and cellulose remained stable during the development of floral buds (6.4, 12.4 and 12.7 %). The GS2 had the highest dietary fiber content (46.3 %). The content of mucilages, loosely bound hemicelluloses and total and soluble dietary fiber increased in floral buds of N. cochenillifera in GS2, followed by their decrease in GS3 and GS4. [ABSTRACT FROM AUTHOR]

Leaf color and area are important characteristics in plant physiology and genetic studies, but data collection is laborious and requires optical integrators and colorimeters. Nowadays, data collection could be automated through digital image analysis (DIA). Free software for DIA to measure leaf area or color is available, but user intervention is required to record dimensions or leaf color. This study shows the Macf-IJ routine for DIA to measure leaf area and color. Results from DIA of seven geometric figures were compared to physical measurements with a LI-COR 3000® Leaf Area Integrator. Additionally, leaf area was measured in 13 herbaceous plants, and color and relative chlorophyll content (RCC) was recorded for Rhynchosia minima (L.) DC with a SPAD 502®. DIA was performed with Digitizer 4.3.5® and Black Spot Leaf. Duration of each measurement was recorded for each case. The area measured with the integrator for any figure varied less than 8.96 % with Macf-IJ and less than 1.82 % with photographs. R2 between methods was 0.999 (p⩽0.001). With exception of five grasses, leaf area measured with the integrator correlated well with the Macf-IJ (r>0.989, p⩽0.001); Macf-IJ, Black Spot Leaf and Digimizer® had an R2 greater than 0.99 (p⩽0.001). Duration was not significantly different between methods, but Macf-IJ registered additional data such as length (cm), width (cm), circularity (0-1) and red (R), green (G) and Blue (B) colors. There was correlation between RCC and green (r=-0.946, p⩽0.01), red (r=-0.941) and blue (r=-0.881) colors and between RGB obtained the Digimizer® and CRC (r=-0.939, -0.942 and -0.811 for red, green and blue colors, respectively). [ABSTRACT FROM AUTHOR]