Characterization of volatiles Tribolium castaneum(H.)in flour using solid phase microextraction–gas chromatography mass spectrometry(SPME–GCMS)

The objective of this study was to identify volatile organic compounds(VOCs)from flour,Tribolium castaneum(Herbst)and flour infested by T.castaneum separately,to confirm the difference of healthy flour and flour infested by T.castaneum and to explore the new technique to diagnose stored flour’s quality by its VOCs change.Headspace-solid phase microextraction(HS-SPME)coupled with gas chromatography(GC)and gas chromatography–mass spectrometry(GC–MS)were used to detect the VOCs of three different samples.Totally,71 different compounds were identified in flour,T.castaneum and T.castaneum infested flour.Therefore,27 VOCs were identified from flour alone,32 VOCs from T.castaneum and 39 VOCs from T.castaneum infested flour.The compound 2-ethyl-2,5-cyclohexadiene-1,4-dione is only found in T.castaneum infested flour.This suggests that 2-ethyl-2,5-cyclohexadiene-1,4-dione can be a useful VOC for detecting T.castaneum in flour.

Optimized Method to Analyze Rose Plant Volatile Organic Compounds by HS-SPME-GC-FID/MSD

A method involving Headspace solid-phase microextraction (HS-SPME) fiber combined with gas chromatography (GC) coupled with flame ionization detection (FID) and gas chromatography with mass spectrometry (GC-MS) was developed and optimized to investigate volatile organic compounds (VOCs) from different tissues (flowers, leaves, stems, rhizosphere and whole plants) of Floribunda and Hybrid Tea roses (intact and cut). Three-phase fiber 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) was used. Two types of chambers (Tedlar bag and glass jar) were evaluated for collection of VOCs and glass jar was selected. Absorbed compounds on the fiber were completely desorbed in the GC injector port at three desorption times (5, 10 and 15 min), and 5 min at 250?C was used. The maximum extraction efficiency for flowers tissues (equilibrium absorption) was achieved 2 h after fiber exposure in the headspace for intact and cut Floribunda and Hybrid Tea flowers. Under the optimized HS-SPME and GC-FID/MS conditions, 1h extraction time was chosen for intact and cut Floribunda and Hybrid Tea leaves and stems. The results demonstrated that 5 cm depth was selected for root and soil part (rhizosphere) for both rose cultivars, and 6 h and 12 h extraction time of VOCs from rhizosphere was achieved for Floribunda and Hybrid Tea, respectively. One hour was chosen for VOCs released from whole rose plants for both cultivars. In this study, the VOC profiles of two rose cultivars were characterized by the optimized HS-SPME-GC method. The different tissues of rose plants gave wide range of the VOCs;also the chromatograms of different cultivars were quite different and the specific VOC pattern of rose types depends on the species. Results from this study demonstrate the feasibility of this method for identifying VOCs from two rose cultivars and the potential use of this method for physiological studies on rose plants or on other floriculture plants.

Optimization of Environmental Factors to Measure Physiological Parameters of Two Rose Varieties

Rose (Rosa hybrida L.) is one of the most important specialty cut flowers produced. Characterization of physiological variability in photosynthetic efficiencies, respiration rate and chlorophyll content is one of the greatest challenges in assessing rose net primary production of flowering, quality of cut flowers and other rose uses. Two modern rose varieties Floribunda and Hybrid Tea were used to optimize different methods for analysing physiological characteristics (photosynthesis rate, respiration rate and chlorophyll content). Many parameters were optimized, five different lights intensity were used (600, 900, 1200, 1500 and 2000 μmol·m-2·s-1) of which 1200 μmol·m-2·s-1 gave the highest photosynthesis rate. Five different measuring times were used (8 am, 10 am, 12 pm, 2 pm and 4 pm) and 12 pm was shown to be the optimum time for measuring photosynthesis rate. Among two different weather conditions (sunny day and cloudy day) sunny day was selected. For respiration rate two different measuring times (1 and 2 hours) after darkness were studied and 1 hour was chosen. Among three different times (10 am, 12 pm and 2 pm) for measuring chlorophyll content, 12 pm was selected. Using these optimized variables will allow researchers to collect robust and reproducible results to be obtained from different studies, and in turn lead to improved yields of horticultural plants.