Plant Growth Inhibitory Activities and Volatile Active Compounds of 53 Spices and Herbs

Abstract

The inhibitory activities of the leachates and volatiles from 53 plant species (spices and herbs) were evaluated against lettuce (Lactuca sativa “Great Lakes 366”) seedling growth using the sandwich and dish pack methods, respectively. With the sandwich method, parsley (Petroselinum sativum) showed the strongest inhibitory effect on lettuce radicle growth (77%), followed by tarragon (Artemisia dracunculus) (72%). However, caraway (Carum carvi), dill (Anethum graveolens) (seed), laurel (Laurus nobilis), rosemary (Rosmarinus officinalis), and sage (Salvia officinalis) were the most inhibitory species (100% inhibition of lettuce radicle and hypocotyl growth inhibition at all distance wells) in the dish pack method. Cardamom (Elettaria cardamomum) and thyme (Thymus vulgaris) also showed strong inhibitory activity (100% for radicle and hypocotyl growth inhibition at all 41 and 58 mm distance wells). The headspace sampling and gas chromatography-mass spectrometry (GC-MS) analysis identified the main inhibitory active compounds as carvone in caraway and dill (seeds), 1,8-cineole in laurel and cardamom, and borneol in thyme. Both camphor and 1,8-cineole were detected in rosemary and sage, and the total activity evaluation showed that camphor was the major inhibitory compound in rosemary, although both compounds played equal roles in sage.

Soil Amendments with Spearmint, Peppermint and Rosemary Enhance the Community of Free-Living Nematodes and Improve Soil Quality, While Having Strikingly Different Effects on Plant Growth

“…Both mint plants are herbaceous, with soft leaves that degrade rapidly [ 8 ], and contain similar amounts of essential oils, which do not differ greatly from each other qualitatively; in the essential oils of both plants, menthol and isomenthone are the major constituents ( Table 1 ). On the other hand, rosemary (Ro) is an evergreen shrub with hard, slowly degrading leaves that contain essential oils, which are rich in such plant-growth-inhibiting allelochemicals as cineol, camphor, and a-pinene [ 12 , 13 ], and persist for long durations in the soil environment [ 8 ]. As a result, the Ro amendment had a very strong negative impact on the growth of the tomato seedlings, contrary to the Ms and Mp.…”

“…For example, Chalkos et al [ 10 ] showed that spearmint compost, when added at a rate of 4% to 8%, stimulated tomato growth, increased soil bacterial and fungal abundance, and inhibited weed emergence. On the other hand, spearmint essential oil and/or its constituents were found to inhibit seedling emergence and the growth of tomato, cotton, and several weeds [ 11 ], whereas the major essential-oil constituents of these three aromatic plants, including carvone, menthol, cineol, and camphor, were found to strongly inhibit both lettuce germination and seedling growth in laboratory experiments [ 12 , 13 ]. The essential oils of all three plants were also proven to be efficient against phytoparasitic nematodes [ 14 , 15 ], while improving through their root exudates the growth of infested sunflower plants [ 16 ].…”

Encapsulated Limonene: A Pleasant Lemon-Like Aroma with Promising Application in the Agri-Food Industry. A Review

“…essential oil and its main compounds limonene (40.92%) and citral (27.46%) facing three important monocot weeds: Avena fatua L., Phalaris minor Retz. and Echinochloa crus-galli (L.) Beauv., demonstrated the low phytotoxicity of the hydrocarbon monoterpene with respect to the whole essential oil and the oxygenated monoterpene [68], corroborating the fact that monoterpene hydrocarbons usually exhibit less potent allelopathic activity than oxygenated ones [67][68][69][70][71][72][73].…”

Seasonal Changes in the Plant Growth-Inhibitory Effects of Rosemary Leaves on Lettuce Seedlings

“…The leaf extract of rosemary was reported to be potentially phytotoxic, and carnosic acid was reported as an allelochemical in the leaves of the plants [ 34 ]. Rosemary leaves also contain volatiles such as 1,8-cineole, which showed inhibitory effects on lettuce growth [ 35 ]. Carnosic acid has only been identified in a few plant species, all of which belong to the Lamiaceae family [ 36 , 37 , 38 ].…”