Síntese de clorofilas e glicoalcalóides em tubérculos maduros de batata armazenados à luz natural

Abstract

RESUMOForam determinados os teores de clorofílas-e glicoalealóides, bem como de protocloroffla e clorofílas a e b, na porção superficial de tubérculos maduros de batata dos cultivares Aracy (IAC-2), Bintje e Porta, armazenados à luz natural por 24 dias. Verificou-se que os teores dessas substâncias foram dependentes do cultivar, do período de armazenamento e da interaçSo entre essas variáveis. Verificou-se, ainda, haver correlações entre os teores dessas substâncias e o período de armazenamento, bem como entre os teores de clorofílas e glicoalealóides totais. Os teores de clorofílas e de glicoalealóides totais podem ser estimados por uma funçSo logística, onde os teores iniciais e finais dessas substâncias sao características de cada cultivar, assim como o sSo suas velocidades de acúmulo líquido.Termos de indexação: Solanum tuberosum L.; batata; glicoalealóides e clorofila; síntese de clorofílas e glicoalealóides; tubérculos armazenados.

Indices for the Assessment of Glycoalkaloids in Potato Tubers Based on Surface Color and Chlorophyll Content

“…Total Chl content showed the highest (r = 0.84) correlation to the total GA contents. This finding agrees with Spoladore et al [36], who reported a strong positive relationship between Chl and GA content in potato tubers. In summary, the overall results of the evaluated parameters indicated that the Hunter a* values, a*/b* ratio, and Chl content could be used as the key indicators of the total GA contents.…”

Effect of light and temperature on the formation of glycoalkaloids in potato tubers

“…According to literature, growth residual activity of potato may occur in darkness, allowing synthesis and degradation reactions such as the glycoalkaloid biosynthesis Spoladore, Zullo, Teixeira, Coelho, & Miranda, 1985). Although some authors (Haddadin, Humeid, Qaroot, & Robinson, 2001;Maine, Bain, & Joyce, 1988;Percival, 1999) have used storage in darkness as a control treatment when studying the glycoalkaloid formation in potato tubers exposed to light, our results suggest that this procedure may not be appropriate for all potato varieties.…”

Pigment formation in potato tubers (Solanum tuberosum) exposed to light followed by darkness

“…. , huizen and Salema 1967, Ohad et al, 1971, P, J, P, An-' stis, 1972, Ph,D, Thesis, Univ, of Catnbridge, UK, Anit is a well known fact that intact potato tubers, exposed stis and Northcote 1973, Zhu et al, 1984, There is also to light, form Chl in their outermost layers with a sJeep electron micrographs of the piastids present in nongradient inwards. The greening process has been stud-irradiated and irradiated tubers found in that literature, ied extensively, though mostly from the practical point These facts show how amylopiasts with double memof view.…”

“…Contrary to the conditions for containingaseriesof vesicles highly variable in number, etiolated leaves which, exposed to light, green within a shape and size. Prolonged irradiation restilts in a difday or two, the greening ofa potato takes several weeks ferentiation within the resides of grana lamellae to be completed (Spoladore et al, 1985), In this respect (de Rezende-Pinto 1962, Badenhuizen and Salema they resemble roots (Powell 1925, Bjom 1%5), To start 1%7, Conover and Pryke 1987), Ch! formation in roots and in potatoes a puise of biue Pchl (whether es£erified or not is not mentioned) has light is favourable (Bergmattn and Berger 1966, Berger been reported in daTk-grown tubers (Spoladore et ai, and Bergtnann 1%7, Bjom 1967, Kamiya et al, 1981, but very little is known about its occurrence and There is comprehensive iiCeraCure on the transition of spectroscopically distinguishable forms the starch grains to chioroplasts (Liljemark and Widoff The present study deals with the early greening 1960, de Rezende-Pinto 1962, Klein et al, 1963, Baden-events, and the different pigments invoived.…”

“…i.n 1,59 14,58 4.53 The fundametital difference in the greening process between roots, potatoes and tissue cultures on the one hatid and etiolated leaves on the other is the very low rate of the former. While etiolated leaves get fully green within 48 h. the greening of a potato takes several weeks (Anstis and Northcote 1973, Spoladore et al 1985, Conover and Pryke 1987, This difference is primarily because of differences in the developmental stage of the plastids and the domination of Pchl species which are not immediately phototransformable. The plastids in roots, potatoes and tissue cultures kept in darkness are in a different developmental stage than those in etiolated leaves.…”