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International Journal of Farming and Allied Sciences Available online at www.ijfas.com ©2014 IJFAS Journal-2014-3-3/299-303/ 31 March, 2014 ISSN 2322-4134 ©2014 IJFAS The Effects of Salinity Stress on Seed Germination and Seedling Growth of Three Medicinal Plants Saba Siadat Jamian1, Sadegh Mehrani1, Kamal Sadat Asilan1*, Avishan Taherkhanchi Tabrizi2 and Alireza Goharian1 1-Department of Agricultural Sciences (Agronomy Engineering), Payame Noor University, Karaj, Iran 2-Department of Agronomy and Plant Breeding, Aboureyhan Campus, University of Tehran, Iran Corresponding author: Kamal Sadat Asilan ABSTRACT: Plants in natural and agricultural conditions are continuously exposed to several biotic and abiotic stresses such as drought, salinity. Salinity is one of the important problem affecting seed germination and plant growth especially in many area of the world. Seed germination is the most sensitive stage to abiotic stresses in medicinal plants which are negatively affected by environmental conditions like salinity. This study was performed to study the effects of salinity stress at critical stage of plant life (seed germination). The effect of salinity stress in form of NaCl at three levels of zero, 5.3, and 8.48 gL-1 on germination and seedling growth of three important medicinal plants. Germination rate and percentage, root length, shoot length, root to shoot length and, root to shoot dry weight ratios, root fresh weight and shoot fresh weight were estimated. Obtained results indicated that salinity decreased germination rate and percentage at the severe salinity level, but increase in these traits were observed in moderate salinity level. We observed different trends in other traits in these three plants. In general, marshmallow has the highest level of drought tolerance in comparison to other plants, especially at moderate NaCl level. In general, it has been concluded medicinal plants studied in this experiment have higher tolerance compared to crop plants at moderate salt levels. Keywords: Psyllium, Marshmallow, Fennel flower, Salinity stress, Germination INTRODUCTION Salinity is one of the most important environmental factors that has a critical influence on the seed germination and seedling establishment. Salinity affects seed imbibition, seed germination and root growth. Seeds are the main way through that plants propagate, and a seed contains all of the genetic material of the plant. As seed germination is the first stage of the plant growth, seedling emergence is critical for plant growth (Khan and Gulzar, 2003). The effect of salinity stress has been carried out on many agricultural crops. However, little work has been done for exploring the possibility of saline soils for the cultivation of medicinal plants. Plantago psyllium L. commonly known as Psyllium has reported as herbal medicine around the world due to its medicinal properties. Recently it has obtained agricultural importance because of its wide use in pharmaceutical and food grade industries worldwide (Li, 2005). Morphologically psyllium is a bushy herb growing in sandy, salty soil, is believed to be native to Asia, the Mediterranean region and North Africa. Psyllium seeds have characteristic of mucilage formation on catching humidity (Li, 2005). Psyllium is cool, laxative, antidiuretic, soothing, harmless, antiacidic, emollient, demulesent and stabilizer. Due to these properties it is largely used in pharmaceutical industry, food preparations, ayurvedic medicine, preparation of crude drugs, etc (Li, 2005). Marshmallow (Althaea officinalis) is a species that originates from Africa, which is used as a medicinal and ornamental plant (Elmastas, 2004). The leaves, flowers and the root of A. officinalis all have medicinal properties. Intl J Farm and Alli Sci. Vol., 3 (3): 299-303, 2014 Marshmallow is traditionally used as a treatment for the irritation of mucous membranes, including use as a gargle for mouth and throat ulcers, and gastric ulcers (Elmastas, 2004). Fennel flower (Nigella sativa) is an annual flowering plant, native to south and southwest Asia. Nigella sativa oil contains an abundance of conjugated linoleic (18:2) acid, thymoquinone, nigellone (dithymoquinone), melanthin, nigilline, damascenine, and tannins (Al-Ghamdi, 2001). Thymoquinone, found in the seed oil extract of N. sativa, has been shown to have anti-neoplastic effects in rats and in cultured human cells from several types of cancer, including pancreatic ductal adenocarcinoma (Al- Ghamdi, 2001). eeds production and technology is an alternative method of industrial propagation and is being used widely for the commercial propagation of a large number of plant species, including many medicinal plants (Ashraf, 1986). The environmental stress such as, salinity are serious obstacles for medical plants and field crops in many areas of the world, especially arid and semiarid regions. Salt stress leads to suppression of plant growth and establishment, however, depending upon plant types, certain stages such as germination, seedling or flowering stage could be the most critical stages for salts stress. Seed germination is first critical and the most sensitive stage in plant growth (Ahmad, 2009) and the seeds exposed to unfavorable conditions like salinity may have to compromise the seedlings establishment (Albuquerque and Carvalho, 2003). The aim of this study was to evaluate the effects of salinity stress in form of NaCl on the germination parameters and seedling growth of three important medicinal plants. MATERIALS AND METHODS In this experiment, the seeds of Psyllium (Plantago psyllium), Marshmallow (Althaea officinalis) and Fennel flower (Nigella sativa) were used for the germination and seedling growth study under salinity stress in form of NaCl. The seeds had been kindly obtained from the National Seed Gene Bank, Karaj, Iran. Before initiation of the experiment, seeds were sterilized with solution of 3% sodium hypochlorite for five minutes. The incubator prior to use was thoroughly washed with tap water followed by a rinsing with distilled water and then sterilized at 170 ºC for 4 hours. The experimental design arranged in a completely randomized design (CRD) with three replications. Then, all the seeds were subjected to sodium Chloride (NaCl) at zero, 5.3 and 8.48 gL-1 NaCl in a dark room. Thirty seedlings from each treatment were randomly selected for fresh and dry weight determination. Seedlings were dried at 65 ºC for 72 hours. The moisture contents of seedlings were determined on oven dry basis (Hussain, 1992). The number of germinated seeds was recorded daily and in the last day traits such as: root length, shoot length, root to shoot length ratio, root to shoot dry weight ratio, root fresh weight, shoot fresh weight and root to shoot fresh weight ratio were measured using five samples from each replicates. Root and shoot lengths were measured using a ruler. Germination percentage (GP) and germination rate (GR) were calculated using following formulas: Germination percentage (GP) = S/T × 100 Germination rate (GR) = (Σ Ni/Di)/S S: Number of germinated seeds T: Total of number seeds Ni: The number of germinated seeds in Di (day) Analysis of variance was carried out using SAS software, Mean comparison was performed using Duncan’s test at the 5% level of significance (P < 0.05). RESULTS AND DISCUSSION Plants indicate great diversity in terms of salinity tolerance. Distribution and survival mainly many plant species depend on the seed ability to complete germination and the seedling ability to establish completely under adversely conditions (Živković, 2007). Most seeds are often located near the soil surface. Salt concentration in the soil surface changes over time. So, the responses of stressed plants must be elucidated. In this study, mean comparisons of germination percentage showed that the highest germination percentage were observed in psyllium independent to stress treatments, but the salinity led to decrease in germination percentage in psyllium and fennel flower seeds (Figure 1). On the other hand, salinity led to more considerable reduction in psyllium when compared to fennel flower plants. The response of marshmallow to salinity was different. So that, application of 5.3 gL-1 decreased the germination percentage, but treatment of seeds with 8.48 gL-1 led to increase germination percentage in marshmallow seeds (Figure 1). Germination rate of these three medicinal plants also showed that the salinity reduced germination rate of psyllium seeds in a dose dependent manner. While, the response of two 300 Intl J Farm and Alli Sci. Vol., 3 (3): 299-303, 2014 other species was completely different, so that application of 5.3 gL-1 decreased germination rate in marshmallow seeds, but increased this trait in fennel flower seeds. Highest level of salinity also increased germination rate of fennel flower seeds, but increased marshmallow seeds (Figure 1).These results are in agreement with results of Khalesro and Aghaalikhani (2008) about sorghum (Sorghum bicolor L.) and pearl millet (Pennisetum americanum L.). Root and shoot growth reduction depends on salt concentration; while, when salt concentration increase, it can be more considerable reduction of growth (Shannon and Grieve, 1999). A number of studies also showed that salinity led to reduction in germination, growth and dry mater production of plants (Munns and Termaat, 1986; Rawson, 1986; Pessarakli, 1991; Munns and Schachtman, 1993; Hajar, 1996). Psyllium Marshmallow Fennel flower Psyllium Marshmallow Fennel flower 70 a a 1.2 a 60 a ab 1 a a 50 b b b 0.8 b 40 b 30 0.6 c c 0.4 20 c c c 10 Germinatio rate 0.2 c 0 0 Germination percentage Control 5.3 gL─1 8.48 gL─1 Control 5.3 gL─1 8.48 gL─1 Figure 1. Effect of salinity stress treatments on germination percentage and germination rate of three medicinal plants Psyllium Marshmallow Fennel flower Psyllium Marshmallow Fennel flower 250 a 250 a 200 200 b 150 150 b 100 100 c c c c cd 50 50 d d cd d d d d Root fresh wight (g) d d Shoot fresh weight (g) 0 0 Control 5.3 gL─1 8.48 gL─1 Control 5.3 gL─1 8.48 gL─1 Figure 2.