Salicylic Acid Alleviates the Adverse Effects of Salt Stress in Torreya grandis cv. Merrillii Seedlings by Activating Photosynthesis and Enhancing Antioxidant Systems

Abstract

BackgroundSalt stress is a major factor limiting plant growth and productivity. Salicylic acid (SA) has been shown to ameliorate the adverse effects of environmental stress on plants. To investigate the protective role of SA in ameliorating salt stress on Torreya grandis (T. grandis) trees, a pot experiment was conducted to analyze the biomass, relative water content (RWC), chlorophyll content, net photosynthesis (Pn), gas exchange parameters, relative leakage conductivity (REC), malondialdehyde (MDA) content, and activities of superoxide dismutase (SOD) and peroxidase (POD) of T. grandis under 0.2% and 0.4% NaCl conditions with and without SA.Methodology/Principal FindingsThe exposure of T. grandis seedlings to salt conditions resulted in reduced growth rates, which were associated with decreases in RWC and Pn and increases in REC and MDA content. The foliar application of SA effectively increased the chlorophyll (chl (a+b)) content, RWC, net CO2 assimilation rates (Pn), and proline content, enhanced the activities of SOD, CAT and POD, and minimized the increases in the REC and MDA content. These changes increased the capacity of T. grandis in acclimating to salt stress and thus increased the shoot and root dry matter. However, when the plants were under 0% and 0.2% NaCl stress, the dry mass of the shoots and roots did not differ significantly between SA-treated plants and control plants.ConclusionsSA induced the salt tolerance and increased the biomass of T. grandis cv. by enhancing the chlorophyll content and activity of antioxidative enzymes, activating the photosynthetic process, and alleviating membrane injury. A better understanding about the effect of salt stress in T. grandis is vital, in order gain knowledge over expanding the plantations to various regions and also for the recovery of T. grandis species in the future.

Fenugreek Seed Extract Enhanced the Growth of Vicia faba and Zea mays Seedlings

“…They revealed the enhanced antioxidant capacity to the marked increase in flavonoids content under ellagic acid treatments. Moreover, Li et al (2014) reported that the salicylic acid treatment significantly reduced the increase in the MDA content in Torreya grandis seedlings under salt stress. Also, we found that wheat seedlings treated with coumarin significantly exhibit higher values of total antioxidant capacity .…”

“…Additionally, tomato plants treated with salicylic acid exhibited a significant improvement in their shoot and root heights as well as their fresh and dry weights (ALWakeel et al, 2012). Moreover, salicylic acid used as a spray solution to the shoots of soybean significantly increase the growth of the shoots and roots under greenhouse or field conditions (Li et al, 2014).…”

“…The effects of exogenously applied salicylic acid on plant physiological processes under optimal environmental conditions are controversial (Janda et al, 2014). In this regard, foliar spray of Torreya grandis with salicylic acid significantly enhanced its chlorophyll content (Li et al, 2014). Moreover, an earlier study reported that the increase or decrease of chlorophyll content in cowpea under salicylic acid treatment was concentration-dependent and genotype specific (Chandra & Bhatt, 1998).…”

“…Also, chlorophyll levels were significantly improved in tomato leaves treated with salicylic acid (ALWakeel et al, 2012). In this context, Li et al (2014) revealed the increase in chlorophyll content in Torreya grandis under salicylic acid treatment to the increase in the activity of certain enzymes, that involved in chlorophyll biosynthesis or reducing chlorophyll degradation, leading to increased net photosynthesis under salt stress tolerance.…”

Exogenous Gibberellic Acid Ameliorates Salinity-Induced Morphological and Biochemical Alterations in Portulaca grandiflora

“…Over the past few years, many methods have been tested to overcome adverse effects of salinity stress on plants, namely mycorrhiza inoculation (Beltrano et al, 2013) hydrogen sulfide priming (Christou et al, 2013), ABA application (Osakabe et al, 2014) and salicylic acid treatment (LI et al, 2014). Previously, Ashraf et al (2002) reported the combining effects of gibberellic acid and salt stress on the photosynthetic capacity of wheat plants.…”