Investigation of yield, phytochemical composition, and photosynthetic pigments in different mint ecotypes under salinity stress.

Salinity stress is one of the main limiting factors of medicinal plant growth and may affect their characteristics and chemical composition. In order to evaluate the response of different species of Iranian mint to salinity stress, an experiment was designed in greenhouse conditions. In this experiment, six Iranian mint species were cultivated in pots under different salinity stress including 0, 2.5, 5, and 7.5 dS/m. The chlorophyll indices (a, b, total, and a/b ratio), carotenoids, total anthocyanin, total phenolic and flavonoid content, antioxidant activity, dry matter yield, and essential oil content were measured in two different harvest stages. Salinity stress affected various measured traits. The results showed that despite the negative effect of salinity stress on photosynthetic pigments, in some ecotypes and species, photosynthetic pigments were not affected by salinity stress. The amount of total phenolic content, total flavonoid content, and total anthocyanin increased in response to salinity stress. The dry matter decreased under salinity stress, but the content of essential oil increased as a result of salinity stress increment. The results of PCA biplot showed that the E16 and E18 ecotypes were separated by a large distance. Among the various ecotypes, E18 had the most desirable traits which can be recognized as a salt-tolerant ecotype. Also, piperita species was the best among the species in all salinity stress levels.

Essential oil composition of sweet basil (Ocimum basilicum L.) in symbiotic relationship with Piriformospora indica and paclobutrazol application under salt stress.

Essential oil content and oil composition of paclobutrazol treated sweet basil (Ocimum basilicum L.) plant inoculated with Piriformospora indica under salt stress were investigated by GC-MS. The results show a slight increase in essential oil content when basil plants subjected to moderate salinity stress (3 dS m-1 of NaCl). It decreased signifiicantly with increasing salinity level to 9 dS m-1. The findings revealed that leaf area, above ground and leaf dry weights, essential oil content and yield were significantly affected by P. indica inoculation, however paclobutrazol application significantly influenced essential oil yield but not content. Fungal symbiosis as well as paclobutrazol application ameliorated the negative effects of salinity on dry matter and essential oil yield. The main constituents found in the volatile oil of O. basilicum in control treatment were Geranial (26.03%), Neral (24.88%) and Estragole (24.78%). The compounds concentrations showed some differences in P. indica and paclobutrazol treatments. The results demonstrate that micorrhiza-like fungi concomitantly increase essential oil production and biomass in sweet basil, a medicinal herb rich in commercially valuable essential oils.

Investigation the growth, yield and yield components of rice varieties in rotation with garlic, Faba bean, lettuce, pea and fallow in north of Iran.

In order to investigating the effects of second crop cultivation on growth, yield and yield components of rice, a field experiment was conducted at the Rice Research Institute of Iran-Deputy of Mazandaran (Amol) during 2004 and 2005. Tarom as a traditional variety and Fajr as a improved variety were used in this research. Faba, pea, Lettuce and garlic were used as a second crop in rotation with rice. Second crop cultivation, variety and interaction between them had a significant effect on tiller number at 0.01 probability level. Results showed that rice yield after lettuce and garlic rotation was lower than with Faba bean, pea and fallow rotation. These results indicated that rice varieties had different reaction to second crop cultivation. For example, Tarom variety in rotation with lettuce and garlic had higher yield deficiency than Fajr variety. These results suggested that Lettuce and garlic can not be a permanent second crop in paddy field. According to results, pea and faba bean in rotation with rice for the best performance of yield attributes of rice varieties were recommended.