Studies on the volatile compounds in flower extracts of Rosa odorata and R. chinensis

Roses are culturally and economically important ornamental plants in the perfume industry. Rosa odorata, the unique rose species in Yunnan region of China, with strong fragrance and abundant varieties, played a prominent role in the formation of modern roses' tea-scent. In the present study, three taxa of Rosa odorata and three taxa of R. chinensis germplasm resources were examined for their chemical profiles of volatile compounds of flower extracts at different flowering stages by sensory analysis and solid phase micro extraction-gas chromatography-mass spectrometry (SPME-GC–MS) analysis. A total of 103 volatile organic compounds (VOC) were detected, including 33 major compounds. The release of total VOC was in the following order: OG (R. odorata var. gigantea) > CSR (R. chinensis var. spontanea Red) > CSW (R. chinensis var. Spontanea White) > COB (R. chinensis 'Old Blush') > OE (R. odorata var. erubescens) > OO (R. odorata var. odorata). The production and release of floral VOC in double flowers were delayed by those in single flowers. Principal component analysis showed that some benzodiazepines and sesquiterpenoids were their characteristic substances, which could separate R. odorata and R. chinensis. R. odorata contained more volatile compounds originated from benzodiazepine metabolic pathway, such as 3,5-dimethoxytoluene and phenyl ethanol, which were not found in R. chinensis. In addition, the release of 1,3,5-trimethoxybenzene in R. chinensis was significantly higher than that in R. odorata. This study could provide a platform for floral gene mining and floral improvement breeding of ornamental plants to develop new raw materials for plant essential oils.