Growth, lipid peroxidation, organic solutes, and anti-oxidative enzyme content in drought-stressed date palm embryogenic callus suspension induced by polyethylene glycol

Abstract

Polyethylene glycol (PEG) can be used in somatic embryogenesis to enhance embryogenic development and improve the success of in vitro culture but PEG also causes osmotic stress in developing embryos. The effects of PEG on embryo growth and development in date palm cell suspension culture and associated antioxidant enzyme activities were evaluated. Callus maintained on MS basal media was transferred to regeneration liquid media supplemented with increasing levels (0-20%) of polyethylene glycol 6000 (PEG) to induce osmotic stress. The degree of embryogenic callus formation, its fresh weight, and the percentage of normal embryo callus shapes were increased with an increase in the level of PEG up to 10%. Total soluble protein (TSP), proline, glycine betaine (GB), total soluble phenol (TSPh), total sugars (TS), and total soluble organic acids (TOA) also increased whereas superoxide dismutase (SOD) activity decreased in response to PEG supplementation. Raising the PEG level increased malondialdehyde (MDA) concentration up to 10% PEG and thereafter decreased. Glutathione reductase (GR) and catalase (CAT) activities decreased at the highest levels of PEG. The proportion of normal embryo developmental shapes were about 50% compared with 20% abnormal shapes at optimum levels of PEG. Proliferation of somatic embryos was influenced by their developmental shapes. Cv. Samani accumulated more organic solutes compared with cv. Sewi in both control and stress inducing media. In contrast, lipid peroxidation, GR, SOD, and CAT activities were significantly higher in cv. Sewi than in cv. Samani indicating that the cv. Samani had the ability to tolerate a higher level of osmotic stress compared to cv. Sewi due to the enhanced osmotic rebalancing within its tissues.

Atmospheric N deposition alleviates the unfavorable effects of drought on wheat growth

“…Earlier results have shown that plant growth performance significantly inhibited under drought (Duan et al 2017;Helaly et al 2017;Hajihashemi and Sofo 2018). The results of this study existed that the ability of productive stem, competitiveness for sunlight acquisition, plant supporting ability, leaf photosynthetic area, leaf growing competitiveness, aboveground growing competitiveness, aboveground moisture content, and belowground growing competitiveness of wheat dramatically declined under PEG 6000 regardless of the concentration.…”

“…Specifically, the drought is expected to get worse in the near future (Walther et al 2009;Liu and Jiang 2015;Jiang et al 2017). However, the increasing drought can recruit numerous effects on the growth performance and metabolism process of plant species, including (I) the altered plant morphological characteristics (Duan et al 2017;Meng et al 2019;Chavoushi et al 2020), plant biomass allocation patterns between belowground and aboveground parts (Xu and Cui 2015;, (II) the raised degree of peroxidation of cell cytoplasm membrane of plant species (Helaly et al 2017;Hajihashemi and Sofo 2018;Zhang and Shi 2018), and (III) the inhibited plant growth performance (Duan et al 2017;Hajihashemi and Sofo 2018;Meng et al 2019;Chavoushi et al 2020). Plant morphological and physiological performance (MorPhyPer) play a key role in their growing competitiveness (Wang et al 2016a(Wang et al , b, 2017aJiang et al 2019).…”

Integrated Application of Proline or Potassium in Alleviating the Adverse Effects of Irrigation Interval on Wheat Plants

“…Proline is an amino acid and compatible solutes and plays a crucial major role in osmoregulation and osmotolerance (Helaly et al 2017). They added that it protects membranes and proteins against the destabilizing effects of dehydration and under stress conditions, it has some ability to scavenge free radicals generated (Ashraf and Foolad 2007).…”

“…On the contrary, POD activities and MDA contents greatly increased in response to water stress (Helaly et al 2017). It is well known that the proline contents in leaves of many plants get enhanced by several stresses including drought stress.…”

“…Caballero et al (2008). Elumalai et al, (2002) reported that the major plant macro-nutrient as potassium plays role of stomatal behavior, activity of enzymes, osmoregulation, cell expansion Osmolytes as proline play a major role in osmotic adjustment and protect the cells by scavenging ROS (Helaly et al, 2017). Proline involved in reducing the photodamage in the thylakoid membranes by scavenging and/or reducing the production of 1 O 2 .…”