Stellaria media belongs to the Caryophyllaceae family, has beneficial therapeutic effects and is used in green and cooked for human food consumption. This plant is highly distributed in Iran. The growth and synthesis of primary and secondary compounds of plants in natural habitats are affected by climatic factors including temperature. In order to study the impact of temperature on growth parameters such as plant dry matter content and protein and also photosynthetic pigments, to determine the appropriate climate and habitat in terms of the amount of parameters mentioned for use in medicinal and nutritional uses, S. media was collected from three regions with different temperature range (5, 10, 17 oC) in five replicates in each region. Then the samples were transferred to the laboratory at 4 oC. Some samples were used to determine the plant dry matter content and some others to determine protein using the Bradford method and also photosynthetic pigments using spectrophotometric method. After statistical analysis, the results showed that the percentage of plant dry matter content has been increased by decreasing of temperature but no significant changes were observed in the content of chlorophyll a, b and carotenoids due to temperature changes. In addition, the findings showed that the protein content in both shoot and root was highest at 17 oC. Generally temperature can be considered as one of the environmental factors affecting growth parameters and photosynthetic pigments.
