Chemical composition and water permeability of the cuticular wax barrier in rose leaf and petal: A comparative investigation.

Cuticular wax is the main transpiration barrier against uncontrolled water loss for all aerial plant organs. This study presents water permeability and chemical composition of the cuticle on the petals and leaves of two cultivars of Rosa chinensis ('Movie star' and 'Tineke'). Numerous cultivar- and organ-specific differences, such as the water permeability and total cuticular wax, were detected among rose petals and leaves. Overall, the permeability to water is higher in petals than in leaves, varying between 1.8 × 10-5 m s-1 ('Tineke' leaves) and 1.0 × 10-4 m s-1 ('Tineke' petals). The cuticular wax coverage ranges from 4.9 µg cm-2 ('Tineke' petals) to 13.2 µg cm-2 ('Movie star' petals). The most prominent components of the waxes are n-alkanes with the odd-numbered chain lengths C27 and C29 in petals, and C31 and C33 in leaves. The lower water permeability of leaves is deduced to be associated with the higher weighted average chain length of their acyclic cuticular waxes. This study on transpiration via the cuticular wax barrier of the leaf and petal of rose provides further insight to link the chemical composition to the cuticular transpiration barrier properties.

Induction of intracellular Ca2+ and pH changes in Sf9 insect cells by rhodojaponin-III, a natural botanic insecticide isolated from Rhododendron molle.

Many studies on intracellular calcium ([Ca2+](i)) and intracellular pH (pH(i)) have been carried out due to their importance in regulation of different cellular functions. However, most of the previous studies are focused on human or mammalian cells. The purpose of the present study was to characterize the effect of Rhodojaponin-III (R-III) on [Ca2+](i) and pH(i) and the proliferation of Sf9 cells. R-III strongly inhibited Sf9 cells proliferation with a time- and dose-dependent manner. Flow cytometry established that R-III interfered with Sf9 cells division and arrested them in G2/M. By using confocal scanning technique, effects of R-III on intracellular free calcium ([Ca2+](i)) and intracellular pH (pH(i)) in Sf9 cells were determined. R-III induced a significant dose-dependent (1, 10, 100, 200 µg/mL) increase in [Ca2+](i) and pH(i) of Sf9 cells in presence of Ca2+-containing solution (Hanks) and an irreversible decrease in the absence of extra cellular Ca2+. We also found that both extra cellular Ca2+ and intracellular Ca2+ stores contributed to the increase of [Ca2+](i), because completely treating Sf9 cells with CdCl(2) (5 mM), a Ca2+ channels blocker, R-III (100 µg/mL) induced a transient elevation of [Ca2+](i) in case of cells either in presence of Ca2+ containing or Ca2+ free solution. In these conditions, pH(i) showed similar changes with that of [Ca2+](i) on the whole. Accordingly, we supposed that there was a certain linkage for change of [Ca2+](i), cell cycle arrest, proliferation inhibition in Sf9 cells induced by R-III.