Effects of Irrigation content based on field capacity percent and Hiumic acid on morphophysiological traits on medicinal plant (Portulaca oleracea L.)

Background and objectives: Since medicinal plants in natural areas spread within the broad geographic limitations and collection and access to them is not costeffective and on the other hand, the use of natural habitats will not be enough for the pharmacy industry, therefore, it is necessary to grow these plants in agricultural areas. In this regard, the choice of the landraces and suitable cultivars and nutrition and irrigation management, play an important role in increasing the quantity and quality of medicinal plants and reduce the negative effects of various environmental stresses on plants.One of the most important environmental stresses is drought that great effect on plant grows and metabolism. In this study, drought stress effect on germination and inorganic elements content in leaves of medical plant Purslane (Portulaca oleraceae L.) were study. This plant as an Antiseptic, Antispasmodic, Diuretic, and Blood Filtering has medical application. According to the drought as the most important environmental factor that limiting agricultural products and using Humic acid as the reducer in evaporation from soil and mentenance water in soil, In this study the effect of Humic acid on some of morphological and physiological charactristics under water stress on medicinal plant of portulaca oleracea was examined.
Materials and Methods: In order to investigate the effects of Irrigation regims and Hiumic acid levels on morphophysiological traits on portulaca (Portulaca oleracea L.), as a medicinal plant a pot experiment was conducted as factorial based on completely randomized design with three replications at Gorgan University of Agricultural Sciences and Natural Resources durong 2014. Treatments included Irrigation rejims in four levels (100 percent FC, control, 75percent FC, 50percent FC and 25percent FC) and humic acid in four levels (0, 200, 400 and 600mg/l). studied traits included the water stress reduced shoot length, number of stem, root diameter, root length, stem wet and dry weight, leaf wet and dry weight, leaf area index, prolin, leaf water ratio and a, b and total chlorophyll content.
Results: The results showed that by increasing drought stress, shoot length, number of stem, root length, stem wet and dry weight, leaf wet and dry weight, leaf area index were decreased. Also, with increasing drought stress, leaf water ratio and a, b and total chlorophyll content decreased and prolin were increased. Humic acid had significant effects on all of morphological and physiological characteristic except of stem wet and dry weight and a, b and total chlorophyll content. Intraction effects of Irrigation regime and humic acid had significant effects on all of morphological and physiological characteristic except of stem wet and dry weight, leaf area index and b chlorophyll content. Proline increased compared to control (72.1%) in 600 mlg/L humic acid. The most value of a and total chlorophyll content was obtained in 100% FC and 200 humic acid. And the most value of LWR was meatured in 100% FC and 400 humic acid.
Conclusion: Generally, the results showed that by increasing drought stress, all of measured traits were decreased, In spite of that, humic acid protected purslane against drought and decreased drought damages. The best treatment is 75percent FC and 200mgr/l humic acid.