Influence of Benzyladenine on Metabolic Changes in Different Rose Tissues

Abstract

Two modern rose varieties, Floribunda and Hybrid Tea, were used to analyze and identify metabolic changes after foliar application with benzyladenine (BA). Volatile organic compounds (VOCs) as metabolites were detected. Two pairs of doses of BA, at 11.16 and 17.87 mg/cm2, and 7.17 and 12.26 mg/cm2 were applied to the foliage of Hybrid Tea and Floribunda, respectively. Sampling time was optimized and treatment duration was 4 weeks. After treatment, the volatiles from the treated and untreated control roses were extracted using headspace solid-phase microextraction (HS-SPME) technology by three-phase fiber 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) and analyzed by gas chromatography (GC) coupled with a flame ionization detector (FID), and with mass spectrometry (GC-MS).The results showed that BA and its dose rate led to metabolic changes of treated roses in comparison with untreated controls. The number of VOCs extracted and detected from leaves, stem, rhizosphere and whole plants from the two rose varieties at doses rate of 17.87 and 12.26 mg/cm2 were 43, 65, 40 and 68 compounds for each plant material, respectively, for both rose varieties. Whilst the VOCs extracted and detected from both rose varieties for leaves, stem, rhizosphere and whole plants were 38, 61, 34 and 66 compounds for each plant material, respectively. The results demonstrate that some volatiles, such as 4-Heptyn-2-ol, Phenyl methyl ether and 3-Methyl-apopinene, increased with increasing doses of BA; these compounds are aroma chemicals with a very powerful smell. This study shows that BA treatments can have a significant effect on metabolite changes in different rose tissues. This method could be applied to other floriculture plants.

Plant Growth Regulators Improve the Production of Volatile Organic Compounds in Two Rose Varieties

“…Next, 100 and 200 mg of BA and NAA were mixed with 4 to 6 drops of liquid sodium hydroxide (NaOH) 1 N and then added to 1 L of double distilled water. The growing conditions, age of plants, application of BA and NAA, and plant maintenance were described previously [ 25 ]. The rose plants were prepared in a factorial-based and completely randomized design with two rose varieties, two hormones, three concentrations of each hormone and three replicate plants for each treatment.…”

“…Naphthalene acetic acid (NAA) (95% purity, product number N0640) was purchased in crystalline form from Sigma-Aldrich (Castle Hill, NSW, Australia). Mohammed et al [ 25 ] described all other standards and regents. Briefly, these included high-performance liquid chromatography grade ethanol, n-hexane (95%), benzyladenine (BA) (98%), sodium hydroxide as a pellet (97%), rooting hormone (Clonex) in gel form, vapor guard (anti-transpirant concentrate) liquid, deionized water (Milli-Q Ultrapure water system) and double distilled water.…”

“…Mass spectra were compared with the retention indices (RI) or GC retention time data of synthetic standards and compounds published in the literature. The same conditions of the GC-MS analysis were employed to ensure reproducibility by using the RESTEK website to translate the conditions (the pure chromatography EZGC method translator) of the GC-FID to GC-MS. A 50/30 µm divinylbenzene/ carboxen/polydimethyl siloxane (DVB/CAR/PDMS) coated fused-silica fiber was used as it is the most suitable fiber for adsorbing VOCs emitted from the headspace of different rose tissues [ 24 , 25 ].…”

“…Comparison of the MS-fragmentation pattern of the target analyses with those of pure components was also performed. The VOC peaks produced by the GC-MS were identified using AMDIS [ 25 ].…”

“…It also prevents the production of artifacts compared with conventional solvent extraction procedures [ 23 ]. This method, coupled with gas chromatograph GC-FID/MS analysis and using the SPME fiber divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), has been successfully applied in the analysis of VOCs emitted from rose plants [ 24 , 25 ]. To our knowledge, there are no studies on the influence of BA and NAA on volatile production from rose flowers using the SPME technique.…”