Funneliformis mosseae inoculation under water deficit stress improves the yield and phytochemical characteristics of thyme in intercropping with soybean

Abstract

Intercropping of medicinal plants/legumes along with bio-fertilizer application is a relatively new sustainable practice for improving the yield and secondary metabolites production. Here, a 2-years field experiment was performed to evaluate the effects of water deficit stress and arbuscular mycorrhizal fungi (AMF) application (as bio-fertilizer) on nutrients concentration, dry matter yield, essential oil quantity and quality of thyme in intercropping with soybean. Three irrigation levels, including (i) irrigation after depletion of 20% (I20) as non-stressed, 50% (I50) as moderate water deficit and 80% (I80) available water as severe water deficit were applied as the main factor. The sub-factor was represented by different cropping patterns including thyme sole culture, replacement intercrop ratio of 50:50 and 66:34 (soybean: thyme) and the third factor was non-usage (control) and usage of AMF. According to our results, the thyme dry yield under moderate and severe water deficit stress decreased by 35 and 44% in the first year, and by 27 and 40% in the second year compared with non-stressed (I20) plants, respectively. Also, the macro- and micro-nutrients of thyme leaves increased significantly in intercropping patterns after application of AMF. The maximum essential oil percentage of thyme was achieved in 50:50 intercropping ratio treated with AMF. Under moderate and severe water deficits, the major constituents of thyme essential oil including thymol, p-cymene and γ-terpinene were increased in intercropping patterns treated with AMF. Generally, AMF application in intercropping ratio of 50:50 may be proposed to farmers as an eco-friendly approach to achieve desirable essential oil quality and quantity in thyme under water deficit stress conditions.

Co-Application of TiO2 Nanoparticles and Arbuscular Mycorrhizal Fungi Improves Essential Oil Quantity and Quality of Sage (Salvia officinalis L.) in Drought Stress Conditions

“…The results indicated that drought stress decreased AMF colonization, which was attributed to the degeneration of population and soil microbial activities as well as decreasing spore germination, spore density, root exudates, and supply carbohydrates by the host plant [31]. Similarly, Amani Machiani et al [27] reported that the AMF colonization rate significantly reduced in drought stress conditions.…”

“…In addition, the decrease in plant performance was due to the lower nutrient availability as a result of the drought impact on the mass flow of N and diffusion of P and K into the plant roots [33]. Similarly, Amani Machiani et al [27] reported that the thyme (Thymus vulgaris L.) DMY reduced with moderate and severe water scarcity due to the decrease in macro-and micro-nutrients uptake in drought conditions.…”

“…The increase in carotenoid content is one of the non-enzymatic defense mechanisms for increasing plant performance [44]. In drought stress conditions, carotenoids have antioxidant, anti-aging, and ROS scavenging activities in plant cells [27,45]. Therefore, the increase in carotenoids reduces the negative effects of drought stress by inhibiting ROS production and lipid peroxidation.…”

“…AMFplants' roots symbiotic relationship enhances nutrient and water uptake and regulates plant physiological functions including leaf water potential, relative water content, stomatal conductance, and CO 2 stabilization [24][25][26]. Previous studies have shown that inoculating plants' roots with AMF increases the EO quantity and quality of medicinal and aromatic plants such as thyme (Thymus vulgaris L.) [27], peppermint (Mentha x piperita L.) [28], and holy basil (Ocimum tenuiflorum L.) [29].…”

Application of humic acid and biofertilizers changes oil and phenolic compounds of fennel and fenugreek in intercropping systems

“…Moreover, intercropping can increase resource use efficiency, including water and nutrients, improve soil fertility to meet plant nutrient requirements, alleviate pest and disease pressure, enhance system stability, and increase crop quantity and quality 17 . Furthermore, intercropping improves the activity of beneficial soil microbes, increasing the availability of micro- and macro-elements 8 , 18 , 19 . Studies have shown that intercropping systems are agronomically and economically viable when the intercropped species consume the resources differently.…”