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.

The effects of host defence elicitors on betacyanin accumulation in Amaranthus mangostanus seedlings.

The effect of elicitors associated with host defence on betacyanin accumulation in Amaranthus mangostanus seedlings was investigated. Under the conditions of the experiments, betacyanin accumulation was generally enhanced by light. Methyl jasmonate (MeJA) treatment increased betacyanin synthesis in a concentration-dependent response. Seedlings treated with ethylene as 5mM Ethephon also had elevated levels of betacyanin. In contrast, salicylic acid (SA) and H(2)O(2) treatments had no influence on betacyanin contents in light or dark. Combined MeJA with Ethephon or H(2)O(2) had an additive effect on betacyanin accumulation in dark-grown seedlings. However, a decline was recorded in light-grown seedlings. Moreover, an antagonistic effect on betacyanin synthesis was found when MeJA and SA were added simultaneously. Our results indicate that betacyanin content in A. mangostanus seedlings can be upregulated by MeJA and ethylene. Both additive and antagonistic effects in regulating betacyanin synthesis in A. mangostanus seedlings were observed between MeJA and other elicitors.

[Determination of nano-silver spatiotemporal distribution in cut gerbera flowers by ICP-AES].

The spatiotemporal distribution of nano-silver in cut gerbera (Gerbera hybrida cv. Crossfire) flowers were determined by inductively coupled plasma-atomic emission spectrometry technique (ICP-AES). The relative standard deviations of this method were between 0.14% and 2.89%, and the recovery ratio obtained by standard addition method ranged from 93.33% to 106.67%. The method was proved to be simple, rapid, reliable and highly sensitive, which can meet the demands of actual sample analysis. The experimental results also showed that Ag could be found in the basal stem end, upper stem end and petal of the cut gerbera flowers treated in nano-silver solution of 5 mg x L(-1) for 24 h and thereafter placed in distilled water. However, the Ag content in basal stem ends was much higher than those in upper stem ends and petals. The results indicated that nano-silver particles could enter into the flower stems through the cuts of stem ends and then moved to different parts of the cut gerbera flowers, but most of them located in the basal stem ends during the vase period. The fact that Ag was centred in basal stem end implied that the positive preservation effects of nano-silver on cut gerbera flowers is related to its strong and sustainable antiseptic action in the stem ends of cut flowers. The above results provide a reliable method for the determination of nano-silver and theoretical basis for its futher research and application in the preservation of cut flowers.