Comparative evaluation of hydro-, chemo- , and hormonal-priming methods for imparting salt and PEG stress tolerance in Indian mustard (Brassica juncea L.)

Abstract

The present study was aimed to evaluate the effect of different seed priming methods to enhance the sodium chloride (NaCl) and polyethylene glycol-8000 (PEG-8000) stress tolerance in Indian mustard (Brassica juncea L.). Seeds subjected to different priming treatments such as water (hydro-priming), calcium chloride (CaCl 2 ) (chemo-priming), and abscisic acid (ABA) (hormonalpriming) showed increased rate of germination as compared to non-primed seeds. The primed and non-primed seeds were grown for 15 days and then the seedlings were independently subjected to iso-osmotic salt (150 mM NaCl) or PEG-8000 (20%) stress. The different biochemical responses were studied 10 days after treatment. Under NaCl and PEG stress, the dry weight and total chlorophyll content were higher in primed sets as compared to nonprimed treatment which was also evident by the phenotype of the seedlings. In general, the higher activities of superoxide dismutase and glutathione reductase resulted in lower oxidative damage, in terms of malondialdehyde content, under NaCl and PEG stress in hydro-primed set as compared to non-primed, ABA-, and CaCl 2 -primed treatments. Besides, the level of total phenolics and accumulation of osmolytes such as free proline, glycine betaine, and total soluble sugars was also lower in hydro-primed set as compared to other primed and non-primed treatments. The study thus suggests the use of hydro-priming as a simple and cost-effective strategy to alleviate the NaCl and PEG induced stress in B. juncea.

COMPARISON BETWEEN HYDRO- AND OSMO-PRIMING TO DETERMINE PERIOD NEEDED FOR PRIMING INDICATOR AND ITS EFFECT ON GERMINATION PERCENTAGE OF AEROBIC RICE CULTIVARS (Oryza sativa L.)

“…Osmo-priming is a successful practice for improving seed germination performance under water stress, drought and salt stress. These results are reinforced by the previous study on improved germination by osmo-priming in wheat (Basra, Zia, Mehmood, Afzal, & Khaliq, 2002;Srivastava et al, 2010). In addition, the increase in priming indicator emergence with priming might be due to initiating metabolic events in primed seed which was corroborated by Elkheir et al (2016) mentioned that soaking rice seed in the water and PEG solutions 100 g L -1…”

“…Earlier reports have shown that seed priming was influenced by many complex interactions of factors and conditions such as plant species, water potentiality of priming agent, soaking duration in priming agent, variation of temperature, seed vigor and dehydration, and storage conditions of the primed seed (Hussain, Farooq, Basra, & Ahmad, 2006). Recent works reported a very comprehensive study on priming where seeds were treated by soaking in different priming agents and treatments such as abscisic acid (ABA) (hormonal priming), calcium chloride (CaCl2) (chemo-priming), and water (hydropriming), showing high performance rate of germination behaviors as compared to nonprimed seeds (Ghiyasi, Seyahjani, Tajbakhsh, Amirnia, & Salehzadeh, 2008;Srivastava et al, 2010).…”

Differential growth, physiological and biochemical responses of niger (Guizotia abyssinica Cass.) cultivars to water-deficit (drought) stress

“…However, these compounds involved in osmotic adjustment differ widely among plant species in response to drought stress (Verslues and Bray 2006;Srivastava et al 2010). Consequently, our studies clearly revealed that the tolerant cultivar (IGPN 2004) showed the highest osmotic adjustment to severe water-deficit stress through more accumulation of proline, glycine betaine and total soluble sugars in comparison to moderately tolerant (IGP 76 and No.…”

“…Significant decrease in chlorophyll content of the cultivars exposed to 80 and 60% FC in comparison to 100% FC (Fig. 4a) might be attributed to the increased degradation of chlorophyll pigments due to stress-induced metabolic imbalance (Ashraf et al 1994;Srivastava et al 2010). Besides, the inhibitory effects of decreased water content on leaf development, reduced light interception and stomatal conductance leading to decrease in carbon assimilation (Medrano et al 2002;Fariduddin et al 2009) might have contributed to decreased chlorophyll content, which ultimately affect the transfer of photosynthetic assimilates from source to sink.…”

“…Abiotic stresses (drought and salinity) are the major environmental constraints, which make taking water from the soil more difficult for the plant, due to an increase in the osmotic pressure of the soil solution as compared to that of roots (Srivastava et al 2010). Nowadays, availability of ample amount of water for crop irrigation is becoming a serious problem; therefore, more efforts have been concerted on the development of crop varieties demanding less water, which can complete their life cycle in drought-prone areas.…”