Autotoxic effects of essential oils on photosynthesis in parsley, parsnip, and rough lemon

Summary. Many plant species contain essential oils with allelochemical properties, yet the extent to which these same chemicals can be autotoxic is unclear. In this study, we tested the toxicity of several essential oil components to three species that produce them—Pastinaca sativa and Petroselinum crispum (Apiaceae), and Citrus jambhiri (Rutaceae). The effects of exogenous application of small amounts of essential oil components to the surface of foliage, followed by a pinprick to allow entry into the leaf, were monitored by chlorophyll fluorescence imaging. Rapid and spatially extensive declines in photosynthetic capacity were detected within 200 s. The most toxic constituents were monoterpenes. Two sesquiterpenes, caryophyllene and farnesene, and the phenylpropanoid myristicin, by comparison, were not toxic. Autotoxicity of endogenous essential oil was investigated by slicing through containment structures (glands or tubes); significant toxicity, manifested by reduced photosynthetic activity, was observed in all three species but was most pronounced in P. sativa and P. crispum, both of which possess oil tubes.     

Application of multivariate statistical approach to identify element sources in parsley (Petroselinum crispum)

The aim of this study was to determine the content of elements in the parsley roots (Petroselinum crispum) of different geographic origin and estimate their possible sources applying chemometric analysis. The concentrations of 13 elements in parsley collected at 12 locations in five districts were examined. Cluster analysis (CA) separated elements into three statistical significant clusters: metalloids, heavy, and essential metals. Principal component analysis (PCA) permitted the reduction of 13 variables to three principal components explaining 82.3% of the total variance. The first component with 48.2% of variance comprises Al, Cu, Fe, Mn, Mo, Zn, and Co. Some of these metals are essential in low concentrations and their presence in plants is of lithogenic origin. Multivariate statistical analysis approach, such as PCA and CA can be used to assess the level of elements in vegetables. These methods can be used to identify sources of elements in plants too.