The seeds were germinated in seedling plastic tray filled up with a mixture of peat moss and coco peat (1:1). The trays were placed in a glass house at the University of Massachusetts, Amherst, USA, in September 2015. After two weeks, seedlings were transplanted into plastic pots (30 cm diameter and 30 cm height, three seedlings per pot). The pots growth media consisted of 2:1:1 ratio of sieved field soil, sand, and leaf mold, respectively. The medium in each pot was supplemented with 5.8 mg P, 3.3 mg N, and 13.8 mg K to warrant the plant growth; the electrical conductivity was 0.3 mS/cm (Beckman EC meter instrument. cedar grove, New jersey, USA); the pH was 8.04. Plants were maintained at the temperature of 18-25 ℃ ; glass house conditions were set as follows: photoperiod, 16 h; relative humidity, 60-70%; light intensity, 180 µmol m 2 s^-1. The source of light was a high pressure sodium lamp in addition to the day light in order to attain 16 h of light per day. Fourty days after planting (establishment period), the uniform sized plants were treated with four different salinity levels including: 0, 30, 60, and 90 mM NaCl. The irrigation with saline solution (250 mL in each pots) was performed every two days . Total amount of NaCl per pot during experiment was 8.75 L. To avoid osmotic shock the salinity treatment started with 15 mM NaCl, and was progressively increased (every two days) to reach the maximum salinity level in each treatment. To prevent water and nutrient leaching, a plastic dish was inserted under each pot and the leached water was given back to pots.

Salinity has negative impact on plant production and stimulates several physiological and biochemical modifications in thyme species. Here, a major decline in dry matter, relative water content (RWC), photosynthetic pigment contents, K⁺, Ca⁺ as well as increase in Na⁺ and EL was observed. Our work showed that T. daenensis was similar to T.vulgaris in terms of tolerance to high levels of salinity stress and both species were moderately tolerant to severe salt stress. It should be noted that T. daenensis, as an Iranian endemic species, competes with commercial species like T. vulgaris as a rich source of phenolic compounds. Furthermore, the relative salt tolerance of both species could be related to the exclusion of Na⁺ from the vascular system in order to protect tissues from salt toxicity and also to the increase of phenolic content and radical scavenging activity. Thus, the plant behavior under salinity stress may be used to boost the production of bioactive compounds to be used on an industrial level for the manufacture of nutraceuticals, functional foods and cosmetics.

One-month-old rooted stem cuttings of three rosescented geranium cultivars, namely Bourbon type, CIM-Pawan and Kelkar were transplanted at 50 × 50 cm plant spacing in the experimental field of Central Institute of Medicinal and Aromatic Plants, Research Center Purara, Uttarakhand, in October 2007. Plants were irrigated immediately after transplanting and further crops were raised following the normal agricultural practices needed to grow the plant. The experimental site is located between the coordinates 28° 60′ and 31° 29′ N, 77° 49′ and 80° 60 m E, and at an altitude of 1250 m in the Kattyur valley. Climatologically, it is categorized as a sub-temperate (1200-1700 m) zone, where monsoon usually breaks in June and continues up to September. Sampling of the rose-scented geranium cultivars was started from March 2008 and taken on the tenth of every month until February 2009. Samples were collected in triplicate in each season. (A, cv. Bourbon type; B, cv. CIM-Pawan; C, cv. Kelkar; I, spring season; II, summer season; III, rainy season;IV, autumn season; V, winter season).

The major components in the essential oil of cv. Bourbon type were geraniol (14.1-34.6%), citronellol (15.2-31.3%), linalool (2.9-9.2%), citronellyl formate (4.4-9.2%), isomenthone (4.5-6.6%), 10-epi-gamma-eudesmol (4.7-6.7%) and geranyl formate (3.8-6.2%). The dominant constituents of the cv. CIM-Pawan essential oil were geraniol (11.9-31.9%), citronellol (16.1-30.2%), citronellyl formate (5.2-8.9%), linalool (3.7-6.4%), isomenthone (4.0-6.3%), 10-epi-gamma-eudesmol (4.4-5.2%) and geranyl formate (4.3-5.0%). However, the chemical composition and odor of cv. Kelkar was quite different from the other two cultivars and the major components found in this oil were citronellol (51.0-63.4%) and isomenthone (9.8-17.8%).

The material was collected from plants cultivated at the Experimental Farm at the Institute of Biotechnology (Caxias do Sul - Rio Grande do Sul State) from November 1998 to July 1999.

Thymol was found to be the most abundant constituent (31.5-52.4%), followed by p-cymene (17.1-34.4%). Thyme possessed a higher oil yield and the oil was richer in oxygenated compounds when harvested in the spring.