Latex and Laticifer Starch Content of Developing Leaves of Euphorbia pulcherrima

Abstract

Laticifer starch accumulation was compared to laticifer growth for developing leaves of Euphorbia pulcherrima Willd. (poinsettia). Measurements of the laticifer‐specific triterpenol, cycloartenol, in latex and in whole leaf extracts were used to calculate the total latex volume in leaves of different developmental stages. Latex volume and starch concentration in the latex were used to determine total laticifer starch and to compare laticifer growth and starch synthesis. Young leaves contained the highest latex and laticifer starch contents on dry wt and leaf area bases. In older expanding leaves, laticifer growth produced an increase in total latex volume accompanied by an increase in total laticifer starch. Laticifer growth and starch accumulation stopped upon cessation of leaf expansion. Starch concentration was similar in latex from all leaves, but differed between plant organs. Thus, laticifer starch accumulation correlated with laticifer growth, but mobilization of the starch out of the laticifer was not observed in old or senescent leaves. This is evidence that laticifer starch grains function within the laticifer independently of degradation or export to other cell types.

Host Plant Resistance in Romaine Lettuce Affects Feeding Behavior and Biology of <I>Trichoplusia ni</I> and <I>Spodoptera exigua</I> (Lepidoptera: Noctuidae)

“…Latex from young and middle-aged leaves was pure white and viscous, whereas latex from mature leaves was watery and translucent (A.S., personal observation). Young leaves of the poinsettia, Euphorbia pulcherrima Wilenow, contained higher amounts of latex and laticifer starch than mature leaves (Spilatro and Mahlberg 1986). The proportionally higher latex amount may have a speciÞc purpose related to plant defense.…”

Romaine lettuce latex deters feeding of banded cucumber beetle: a vehicle for deployment of biochemical defenses

“…Thus, latex from young leaves may be richer in dispersing particles, and the relatively higher amount of dispersing particles may have a specific purpose related to plant defense. Young leaves are typically better defended than mature leaves due to the presence of higher quantities of latex and its associated chemical components (Swain, 1977; Spilatro & Mahlberg, 1986). In the chicory plant, Cichorium intybus L. (Asteraceae), sesquiterpene lactones were present in the highest amounts in the most actively growing regions of the plant and possessed antifeedant properties against Schistocerca gregaria Forskål (Orthoptera: Acrididae) (Rees & Harborne, 1985).…”

“…Stickiness can result in the entrapment or gumming up of the mouthparts of herbivorous insects (Dillon et al., 1983; Dussourd, 1993, 1 995; Zalucki & Malcolm, 1999). Latex contains toxic constituents including alkaloids (Roberts, 1987; Valle et al., 1987; Konno et al., 2006), cardiac glycosides (Zalucki & Brower, 1992; Zalucki & Malcolm, 1999), and terpenoids (Evans & Schmidt, 1976; Rees & Harborne, 1985; Spilatro & Mahlberg, 1986). Some insects circumvent the mechanical stickiness and toxic effects of latex by severing laticifers or by cutting trenches prior to consuming the distal tissue (Dussourd, 1993; Zalucki & Malcolm, 1999; Sethi et al., 2006).…”

Gebruik Van Euphorbia Tirucalli Als Rubberleverancier En Energiegewas

“…De door hen bekomen rubbergehalten zijn sterk uiteenlopend. Bij een reeks andere planten is echter ook al aangetoond dat de samenstelling van de latex varieert onder invloed van het oogsttijdstip, van de plaats op de plant waar de latex wordt gewonnen (zie ook Watt & Breyer-Brandwijk, 1962), van de gevolgde procedure en van de omgevingsfactoren (Spilatro & Mahlberg, 1986).…”