Phenotypic Plasticity for Growth and Nutrient Uptake in Milk Thistle under Salt Stress: Modulatory Role of Soil Supplementations with Plant Growth Promoters

Salinity stress negatively affects key physiological phenomena in plants while plants show great variability and respond differentially for tolerance to salt stress. Usually, nutrients imbalances affect specific plant tissues and physiological processes which are requisite for normal plant growth and development. The aim of this two-year (2017 and 2018) simulated field study was to investigate phenotypic plasticity for growth, relative leaf water content (RLWC) and nutrient status in milk thistle [Silybum marianum (L.) Gaertn.] ecotypes and the potential role of soil supplementation with pre-optimized levels of plant growth promoters (PGPs) in modulating these attributes under control and salinity (12 dS/m) stress. Four ecotypes of milk thistle were collected from three ecologically distinct zones including Faisalabad (FSD) and Kalar Kahar (KK) – semi-arid zone, Gujranwala (GUJ) – hot semi-arid zone and Quetta (QTA) – cool semi-arid zone. The studied nutrients were nitrate-N, phosphate-P, sulfate-S, sodium (Na), potassium (K) and calcium (Ca). The soil supplemented PGPs, applied with irrigation water, were ascorbic acid (AsA), thiourea (TU) and moringa leaf extract (MLE) at 250 μM, 500 μM and 3%, respectively of soil moisture content at field capacity. Results indicated that soil supplementation of PGPs in the field conditions is a feasible approach for enhancing nutrient uptake of milk thistle ecotypes under salt stress, while the effect of salinity stress restricted the uptake of the studied nutrients and caused their imbalance. Although the salinity stress reduced shoot and root dry matter, RLWC and restricted the uptake of these nutrients irrespective of ecotypes, the levels of nitrate-N, phosphate-P, K, sulfate-S, Ca, and RWC contents increased more with the soil supplementation of AsA followed by MLE as compared to other soil supplements in both the study years. Among the ecotypes, QTA followed by KK and FSD ecotypes gained more dry weight with greater leaf RWC and higher tissue nutrient contents due to PGPs under salt stress. The principal component analysis and correlation data revealed the existence of distinct phenotypic plasticity in the milk thistle ecotypes for nutrient acquisition with soil supplementation of PGPs under salinity stress. To conclude, ecotypes from QTA and KK were more promising than the others while AsA and MLE were better soil supplements in improving shoot and root nutrients under salt stress. © 2021 Friends Science Publishers

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Plant growth promoters mediated quality and yield attributes of milk thistle (Silybum marianum L.) ecotypes under salinity stress

Scientific Reports ◽

10.1038/s41598-021-02435-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Noreen Zahra ◽

Abdul Wahid ◽

Muhammad Bilal Hafeez ◽

Mohammed Nasser Alyemeni ◽

Tariq Shah ◽

...

Keyword(s):

Plant Growth ◽

Salinity Stress ◽

Leaf Extract ◽

Climatic Conditions ◽

Milk Thistle ◽

Silybum Marianum ◽

Growth Promoters ◽

Yield Attributes ◽

Plant Growth Promoters ◽

Moringa Leaf Extract

AbstractSilybum marianum (L.) Gaertn (Astraceae) is a well-reputed medicinal plant mostly utilized for silymarin (Sily) content and oil production, however, the information about Sily contents in achene part is still fragmented under different climatic conditions. In this study four milk thistle ecotypes from Faisalabad (FSD), Gujranwala (GUJ), Quetta (QTA), and Kallar kahar (KK) having an altered achene color were analyzed under salt stress. Application of plant growth promoters (PGPs) is one of the solution for ameliorating the effect of salinity and increasing the quantity and quality traits of milk thistle, so ascorbic acid (AsA), thiourea (TU), and moringa leaf extract (MLE) were soil supplied after developing salinity stress (120 mM with irrigation) at germination stage. Predetermined levels were selected for PGPs such as AsA (500 µM), MLE (3%), and TU (250 µM). Results revealed that all yield related attributes were significantly decreased, while secondary metabolites, pericarp epidermis, pericarp parenchyma, and pericarp seed integument increased under salinity stress. Data suggested that PGPs treatment was helpful to alleviate the deleterious effects of salinity stress and enhance the milk thistle quality and quantity parameters. The ecotypic variations with altered achene color patterns represent an advantage for QTA ecotypes for higher Sily extraction under salt stressed conditions.

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ROLE OF ENDOPHYTIC PSEUDOMONAS AS PLANT GROWTH PROMOTERS UNDER DESERT CONDITION

Egyptian Journal of Desert Research ◽

10.21608/ejdr.2016.6500 ◽

2016 ◽

Vol 66 (2) ◽

pp. 305-326 ◽

Cited By ~ 1

Author(s):

Amal Omer

Keyword(s):

Plant Growth ◽

Growth Promoters ◽

Plant Growth Promoters

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Protection of Photosynthesis by Halotolerant Staphylococcus sciuri ET101 in Tomato (Lycoperiscon esculentum) and Rice (Oryza sativa) Plants During Salinity Stress: Possible Interplay Between Carboxylation and Oxygenation in Stress Mitigation

Frontiers in Microbiology ◽

10.3389/fmicb.2020.547750 ◽

2021 ◽

Vol 11 ◽

Author(s):

Zarin Taj ◽

Dinakar Challabathula

Keyword(s):

Oryza Sativa ◽

Salt Stress ◽

Plant Growth ◽

Salinity Stress ◽

Stress Conditions ◽

Tomato Plants ◽

Rice Plants ◽

Atp Levels ◽

Ros Accumulation

Tomato (Lycoperiscon esculentum) and rice (Oryza sativa) are the two most important agricultural crops whose productivity is severely impacted by salinity stress. Soil salinity causes an irreversible damage to the photosynthetic apparatus in plants at all developmental stages leading to significant reduction in agricultural productivity. Reduction in photosynthesis is the primary response that is observed in all glycophytic plants during salt stress. Employment of salt-tolerant plant growth-promoting bacteria (PGPB) is an economical and viable approach for the remediation of saline soils and improvement of plant growth. The current study is aimed towards investigating the growth patterns and photosynthetic responses of rice and tomato plants upon inoculation with halotolerant PGPB Staphylococcus sciuri ET101 under salt stress conditions. Tomato and rice plants inoculated with PGPB showed increased growth rate and stimulated root growth, along with higher transpiration rates (E), stomatal conductance (gs), and intracellular CO2 accumulation (Ci). Additionally, correlation of relative water content (RWC) to electrolyte leakage (EL) in tomato and rice plants showed decreased EL in inoculated plants during salt stress conditions, along with higher proline and glycine betaine content. Energy dissipation by non-photochemical quenching (NPQ) and increased photorespiration of 179.47% in tomato and 264.14% in rice plants were observed in uninoculated plants subjected to salinity stress. Furthermore, reduced photorespiration with improved salinity tolerance is observed in inoculated plants. The higher rates of photosynthesis in inoculated plants during salt stress were accompanied by increased quantum efficiency (ΦPSII) and maximum quantum yield (Fv/Fm) of photosystem II. Furthermore, inoculated plants showed increased carboxylation efficiency of RuBisCO, along with higher photosynthetic electron transport rate (ETR) (J) during salinity stress. Although the total cellular ATP levels are drastically affected by salt stress in tomato and rice plants along with increased reactive oxygen species (ROS) accumulation, the restoration of cellular ATP levels in leaves of inoculated plants along with decreased ROS accumulation suggests the protective role of PGPB. Our results reveal the beneficial role of S. sciuri ET101 in protection of photosynthesis and amelioration of salinity stress responses in rice and tomato plants.

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