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Abstract
Flavonoids isolated from ‘Better Times’ rose petals were cyanidin 3,5-diglucoside, the 3-rhamnoside, 3-glucoside, 3-arabinoside, 3-glucuronide of quercetin and the 3-glucoside, and 3-xyloside of kaempferol. The rose pigment, a co-pigment complex of cyanindin 3,5-diglucoside (2.0-2.8 × 10-2M) and quercetin or kaempferol glycosides, (0.8-1.4 × 10-1M, expressed as quercitrin) was present only in epidermal cells. At the pH of freshly harvested tissue (3.70 to 4.15) this pigment was red with a λmax of 539 nm. As the tissue aged the pH increased (4.40 to 4.50) and the pigment became more blue with a λmax of 543 nm. Cornell preservative prevented the increase in pH of commercial cut roses and maintained their original color. The high pigment concn and the phenomenon of co-pigmentation explain the intense color of ‘Better Times’ roses in a pH range where anthocyanins alone are virtually colorless.
Abstract
A near-infrared reflectance (NIR) technique was developed that provides a rapid, nondestructive, nonchemical analysis of ground apple (Malus domestica Borkh.) leaf tissue for predicting total N content. Leaf tissue samples of apple with known (chemical) leaf N concentrations ranging from about 1.6% to 2.9% N were used in the calibration of the NIR technique. The NIR technique was highly correlated (r = 0.923) with the chemically determined total leaf N content. Prediction of tissue N values was performed with a standard error of estimate of about ±0.10% N. This value compares favorably with the standard error obtained for duplicate determinations preformed by a tissue analysis facility employing standard chemical (Kjeldahl) digestion methodology.
Abstract
The anthocyanin isolated from flowers of Limonium cvs. Twilight Lavender and Midnight Blue was delphinidin 3,5-diglucoside, and that from ‘Blue Bonneť and ‘American Beauty’ was delphinidin 3-glucoside. The major flavonoid co-pigments in all 4 cvs. were luteolin and its 6-C-glucoside (iso-orientin). These co-pigments were also present in white ‘Iceberg’ and yellow ‘Gold Coast’. The range of colors from reddish-purple to blue for the various cvs. was directly related to the pH of the tissue.