Growth and Digoxin Content inDigitalis lanatain Controlled Conditions and Natural Environment

Abstract

In two different populations of Digitalis lanata (P7 interbreeding, L 3-2A first generation inbreeding),the influence of environmental and genetic factors relative to digoxin production have been studied in controlled conditions and in the field. In controlled conditions (artificial light of 300 ixflnf2r'), digoxin content first increased rapidly and then became stable. At the end of the increasing phase, plants had reached the morphologic stage "dense rosette" and digoxin content was maximal. Under weaker natural light conditions (from November to March), the increase of digoxin content progressed more slowly and digoxin was always lower than under controlled conditions (artificial light). In this condition, the "dense rosette" stage was never reached. In field under natural lighting of May to October, a fast increasing phase of digoxin content was observed, but past August-September this content decreased. The influences of lighting intensity, photoperiod, and thermoperiod on digoxin and implications concerning the selection are discussed.

Seasonal cardenolide production and Dop5βr gene expression in natural populations of Digitalis obscura

“…These results are quite similar to those reported by Brugidou et al (1988) in D. lanata plants grown in controlled conditions and natural environment. These authors found that the variability in cardenolide production of D. lanata, expressed as digoxin contents, was related with the seasonal variations of light intensity, photoperiod and thermoperiod.…”

“…3). In this respect, Brugidou et al (1988) pointed out photoperiodism and a more accented daily thermoperiodism of late summer and early autumn as the main factors involved in the decrease of digoxin rate in D. lanata plants. Nevertheless, the fact that cardenolides have been found in different sink organs and move around phloem sap (Vogel and Luckner, 1981;Rothe et al, 1999) suggests that catabolism and translocation may also provoke a decrease in the leaf cardenolide contents during the autumn.…”

“…Thus, it is known the influence that mineral nutrients (Gavidia and P erez-Berm udez, 1997;Roca-P erez et al, 2004), CO 2 and water stress (Stuhlfauth et al, 1987), and light conditions (Brugidou et al, 1988) exert on cardenolide accumulation. Moreover, other studies on different cardiac glycoside-producing species showed that the production of these compounds seems to be related to plant biomass (Kosinski, 1996) or defence responses against damage caused by feeding of herbivores (Malcolm and Zalucki, 1996).…”

Avaliação quantitativa de cardenolídeos no cultivar experimental de Digitalis lanata do maciço do itatiaia e perspectivas de seu emprego industrial

“…A grande variação individual nas concentrações de cardenolídeos no cultivar experimental já era esperada, uma vez que estas plantas não foram submetidas a nenhum processo de seleção, sendo constituídas por indivíduos com uma ampla base genética. Avaliações anteriores em populações nativas e cultivares de D. lanata, de diferentes origens, indicaram uma alta variabilidade intra-específica nos teores dos cardenolídeos quantificados 5,6,7,12,15 que este material resultou da clonagem de plantas selecionadas, sendo constituído por uma base genética estreita.…”

Investigation of Relationship Between Chemical Stress Factors and Certain Metabolites Including Cardenolides in Callus Cultures of Endemic Turkish Digitalis L. Species

“…In the case of Digitalis plants, previous studies have reported that cardenolide biosynthesis is basically dependent on morphological differentiation [22] and genotype [23], although numerous environmental factors may determine, in a greater or lesser degree, plant productivity. Thus, it is known the influence that mineral nutrients [24,25], CO2 and water stress [26], and light conditions [27] exert on cardenolide accumulation. Moreover, in our previous papers, we showed that H2O2 pre-treatment [15] and elimination of Ca, Mg or both from the medium [28] resulted in an increase in cardenolides, enzymatic and non-enzymatic antioxidants in callus cultures of Digitalis davisiana Heywood, Digitalis lamarckii Ivanina, Digitalis trojana Ivanina and Digitalis cariensis Boiss.…”