A. Mazarie; S.M. Mousavi-nik; A. Ghanbari; L. Fahmideh
Abstract
Water deficit stress is a major environmental limiting factor for plant growth and crop productivity. In present investigation, to study the effects of jasmonic acid on reducing the damage caused by drought on growth parameters, some physiological and antioxidant responses on Salvia officinalis L., a ...
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Water deficit stress is a major environmental limiting factor for plant growth and crop productivity. In present investigation, to study the effects of jasmonic acid on reducing the damage caused by drought on growth parameters, some physiological and antioxidant responses on Salvia officinalis L., a factorial experiment in a completely randomized design with three replications was conducted at the University of Zabol. The experimental treatments included drought stress (irrigated in field capacity, depletion of soil water content up to 50% and 75% of FC condition) and foliar jasmonic acid spray (0, 75 and 150 mg.l-1). The results showed that spraying with a concentration of 150 (mg. l-1) jasmonic acid under drought stress increased the height (% 10.02), fresh and dry weight (27.88% and 12.81%), relative water content (21.04%) and chlorophyll a and b content (12.15% and 10.34%). The highest phenolic content (34.13 mg-1fw), proline concentration (5.52 mg-1fw), essential oil yield (2.1 mg-1fw) and the activities of peroxidase (3.15 mg-1fw) and guaiacol peroxidase (0.76 mg-1fw) were obtained in plants sprayed with 150mg.l-1 jasmonic acidand in depletion of soil water content up to 75% of FC. On the other hand, the highest ascorbate peroxidase (0.76 mg-1fw), superoxide dismutase (5.64 mg-1fw) and catalase (5.12 mg-1fw), were obtained in plants sprayed with 150 mg -1 jasmonic acid under drought stress (depletion of soil water content up to 75 and 50% FC). Based on our results, it seemed that Jasmonic acid, with increasing antioxidant defense and accumulation of osmotic regulators (such as proline), reduced the oxidative stress in plants under drought stress. Moreover, maintaining the relative water content and photosynthetic pigment improved growth conditions of sage plants in drought conditions.
A. Mazaraei; A.R. Sirousmehr; Z. Babaei
Abstract
Drought stress, temporally or permanently, is a more limiting factor in growth and distribution of vegetation cover than other environmental factors. In order to study the effects of vesicular arbuscular mycorrhizal and drought stress on growth and yield of Milk thistle (Silybum marianum (L.) Gaertn.), a ...
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Drought stress, temporally or permanently, is a more limiting factor in growth and distribution of vegetation cover than other environmental factors. In order to study the effects of vesicular arbuscular mycorrhizal and drought stress on growth and yield of Milk thistle (Silybum marianum (L.) Gaertn.), a pot experiment was performed as factorial based on completely randomized design in three replications in the research greenhouse of Chahnimeh at the University of Zabol. Drought stress consisted of two levels including %60 and %30 of field capacity and full irrigation as control treatment. Three mycorrhizal fungi including Glomus mosseae, Glomus versiformis, and Glomus intraradices were investigated. The results showed that after starting of drought stress, vegetative characteristics such as number of capituls, number of seeds in capitul, 1000 seeds weight, leaf number and area, root length, number of minor branches, plant height, and dry weight of leaf, stem and root, significantly decreased with increasing drought stress. RWC of leaf was intensely affected by drought and decreased from 77.3 in control treatment to 57.01 in 30% of field capacity irrigation treatment. In addition, with increasing drought stress, the amount of phosphorus in leaves decreased and the amount of potassium increased. Osmotic adjustment in Milk thistle was increased in response to drought stress and leaf proline content increased (the highest 0.13 mg/g tissue in 30% of field capacity treatment); however, silimarin content decreased from 16.35 in full irrigation to 10.24 in 30% of field capacity treatment. Inoculation with VAM significantly increased vegetative indices, silimarin content (the highest in G. mosseae application and the lowest in control), plant RWC, and leaf content of P and K under drought stress conditions compared to uninoculated plants; however, the leaf proline content was low. In general, application of mycorrhizae fungi increased drought stress resistance in Milk thistle.