Triacontanol hormone stimulates population, growth and Brilliant Blue R dye removal by common duckweed from culture media

Mitigation of salt stress in Indian mustard (Brassica juncea L.) by the application of triacontanol and hydrogen sulfide

Salinity stress is a well-known abiotic stress that has been shown to have a negative impact on crop growth, production, and soil richness. The current study was intended to ameliorate salt stress in Indian mustard (Brassica juncea L.), keeping in mind the detrimental influence of salt stress. A pot experimentation was executed on B. juncea to examine the efficacy of exogenous application of triacontanol (TRIA) and hydrogen sulfide (H₂S) (NaHS donor), either alone or in combination, on growth attributes, metabolites, and antioxidant defense system exposed to salt stress at three distinct concentrations (50, 100 and 150 mM NaCl). Increase in the concentration of oxidative markers (malondialdehyde and hydrogen peroxide) was found which results in inhibited growth of B. juncea. The growth characteristics of plant, such as root and shoot length, fresh and dry weight under salt stress, were improved by foliar application of TRIA (150 µM) and H₂S (25 µM) alone as well as in combination. Additionally, salt stress reduced the levels of protein, metabolites (flavonoids, phenolic and anthocyanin), antioxidant enzyme activity including that of ascorbate peroxidase, catalase, polyphenol oxidase and guaiacol peroxidase as well as the level of ascorbic acid and glutathione (non-enzymatic antioxidants). However, application of TRIA and H₂S alone or in grouping substantially raised the content of protein, metabolites and antioxidant defense system in plants of B. juncea.

Unravelling the Effect of Triacontanol in Combating Drought Stress by Improving Growth, Productivity, and Physiological Performance in Strawberry Plants

To explore the effects of triacontanol (TR) on drought tolerance of strawberry plants (cv Fertona), two field experiments were carried out to study the effects of three supplementary foliar TR rates (0, 0.5, and 1 ppm) under the following three levels of water irrigation: 11 m³/hectare (40% of water holding capacity (WHC) severe as a drought treatment, 22 m³/hectare (80% of WHC) as moderate drought stress, and normal irrigation with 27 m³/hectare (100% of WHC) server as a control treatment. TR treatments were applied five times after 30 days from transplanting and with 15-day intervals. The results showed that drought stress (40% and 80%) markedly decreased the growth, fruit yield, and chlorophyll reading, as well as the gas exchange parameters (net photosynthetic rate, stomatal conductance, and transpiration rate). Meanwhile, drought stress at a high rate obviously increased antioxidant enzyme activities such as superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT) contents in the leaves of the strawberry plants. The moderate and high drought stress rates enhanced some strawberry fruit quality parameters such as total soluble solids (TSS), vitamin C, and anthocyanin content compared to the control. Additionally, TR increased the activities of SOD, POX, and CAT. TR treatment significantly increased the chlorophyll contents, gas exchange parameters (photosynthetic rate and stomatal conductance), and water use efficiency (WUE). Plant height, fruit weight, and total biomass were increased also via TR application. Total yield per plant was increased 12.7% using 1 ppm of TR compared with the control. In conclusion, our results suggested that TR application could relieve the adverse effects of drought stress on the growth of strawberry plants by enhancing the antioxidant enzymes, photosynthesis rate, and WUE of the leaves.

Triacontanol modulates salt stress tolerance in cucumber by altering the physiological and biochemical status of plant cells

Cucumber is an important vegetable but highly sensitive to salt stress. The present study was designed to investigate the comparative performance of cucumber genotypes under salt stress (50 mmol L^-1) and stress alleviation through an optimized level of triacontanol @ 0.8 mg L^-1. Four cucumber genotypes were subjected to foliar application of triacontanol under stress. Different physiological, biochemical, water relations and ionic traits were observed to determine the role of triacontanol in salt stress alleviation. Triacontanol ameliorated the lethal impact of salt stress in all genotypes, but Green long and Marketmore were more responsive than Summer green and 20252 in almost all the attributes that define the genetic potential of genotypes. Triacontanol performs as a good scavenger of ROS by accelerating the activity of antioxidant enzymes (SOD, POD, CAT) and compatible solutes (proline, glycinebetaine, phenolic contents), which lead to improved gas exchange attributes and water relations and in that way enhance the calcium and potassium contents or decline the sodium and chloride contents in cucumber leaves. Furthermore, triacontanol feeding also shows the answer to yield traits of cucumber. It was concluded from the results that the salinity tolerance efficacy of triacontanol is valid in enhancing the productivity of cucumber plants under salt stress. Triacontanol was more pronounced in green long and marketer green than in summer green and 20252. Hence, the findings of this study pave the way towards the usage of triacontanol @ 0.8 mg L^-1, and green long and marketer genotypes may be recommended for saline soil.

Tolerance and decolorization potential of duckweed (Lemna gibba) to C.I. Basic Green 4

With growing human culture and industrialization, many pollutants are being introduced into aquatic ecosystems. In recent years, dyes have become a major water pollutant used in the manufacture of paints and other production purposes. In this research, the potential of duckweed (Lemna gibba) plant was investigated spectrophotometrically as an obvious bioagent for the biological decolorization of the organic dye C.I. Basic Green 4 (Malachite Green, BG4). Photosynthetic efficiency analysis showed that the photosynthetic apparatus of L. gibba is very tolerant to BG4. Significant induction of reactive oxygen species (ROS) scavenging enzymes was observed after 24h of biodecolorization process in L. gibba treated with 15 and 30 mg/l BG4. The experimental results showed that L. gibba has a strong ability to extract BG4 from contaminated water and the best results were obtained at 25–30°C and pH 8.0. We conclude that duckweed L. gibba can be used as a potent decolorization organism for BG4.

Effect of foliar applied triacontanol on wheat (Triticum aestivum L.) under arsenic stress: a study of changes in growth, yield and photosynthetic characteristics

In this study, changes in growth, yield and photosynthetic characteristics were assessed by foliar application of triacontanol (TRIA) in wheat (Triticum aestivum L.) varieties Anaj-2017, Ujala-2016 and AARI-2011 under arsenic (As) stress. Seeds of all three wheat varieties were sown in sand filled plastic pots. The experiment was conducted in a completely randomized design (CRD) with three replicates. All the plants were irrigated with full strength Hoagland's nutrient solution till the termination of experiment. Plants were applied with three levels of sodium arsenite (NaAsO₂) i.e. 0 ppm, 50 ppm and 100 ppm and two levels of foliar treatment of triacontanol i.e. control (no spray), and TRIA 1 µM applied. After 16 week of germination, data of all photosynthetic characteristics was collected, while yield was taken at maturity. Arsenic (50 ppm and 100 ppm) stress exerted significantly adverse effects on various growth and photosynthetic parameters i.e. shoot fresh and dry weights, total leaf area per plant, total grain yield per plant, 100 grain weight, number of seeds per plant, chlorophyll (chl.) pigments, chl. a, b chl. a/b ratio, flavonoids, anthocyanin contents, rate of photosynthesis (A), transpiration rate (E), internal CO₂ concentration (C _i), water use efficiency (A/E), and stomatal conductance (g _s). Foliar application of TRIA significantly increased growth and yield attributes, chlorophyll b, internal CO₂ concentration, stomatal conductance, rate of photosynthesis, flavonoids and anthocyanin contents in all wheat varieties. Moreover, the results also indicated that 1 µM TRIA proved to be effective in reducing the adverse effects of arsenic stress on all three wheat varieties. Of three wheat varieties, AARI-2011 is more sensitive to arsenic stress and Anaj-2017 proved to be more tolerant against arsenic stress. However, foliar application of TRIA proves to be more effective for var. AARI-2011.

Application of common duckweed (Lemna minor) in phytoremediation of chemicals in the environment: State and future perspective

Over the past 50 years, different strategies have been developed for the remediation of polluted air, land and water. Driven by public opinion and regulatory bottlenecks, ecological based strategies are preferable than conventional methods in the treatments of chemical effluents. Ecological systems with the application of microbes, fungi, earthworms, plants, enzymes, electrode and nanoparticles have been applied to varying degrees in different media for the remediation of various categories of pollutants. Aquatic macrophytes have been used extensively for the remediation of pollutants in wastewater effluents and aquatic environment over the past 30 years with the common duckweed (L. minor) as one of the most effective macrophytes that have been applied for remediation studies. Duckweed has shown strong potentials for the phytoremediation of organic pollutants, heavy metals, agrochemicals, pharmaceuticals and personal care products, radioactive waste, nanomaterials, petroleum hydrocarbons, dyes, toxins, and related pollutants. This review covers the state of duckweed application for the remediation of diverse aquatic pollutants and identifies gaps that are necessary for further studies as we find pragmatic and sound ecological solutions for the remediation of polluted environment for sustainable development.

Phytoremediation of textile dyes and effluents: Current scenario and future prospects

Phytoremediation has emerged as a green, passive, solar energy driven and cost effective approach for environmental cleanup when compared to physico-chemical and even other biological methods. Textile dyes and effluents are condemned as one of the worst polluters of our precious water bodies and soils. They are well known mutagenic, carcinogenic, allergic and cytotoxic agents posing threats to all life forms. Plant based treatment of textile dyes is relatively new and hitherto has remained an unexplored area of research. Use of macrophytes like Phragmites australis and Rheum rhabarbarum have shown efficient removal of Acid Orange 7 and sulfonated anthraquinones, respectively. Common garden and ornamental plants namely Aster amellus, Portulaca grandiflora, Zinnia angustifolia, Petunia grandiflora, Glandularia pulchella, many ferns and aquatic plants have also been advocated for their dye degradation potential. Plant tissue cultures like suspension cells of Blumea malcolmii and Nopalea cochenillifera, hairy roots of Brassica juncea and Tagetes patula and whole plants of several other species have confirmed their role in dye degradation. Plants' oxidoreductases such as lignin peroxidase, laccase, tyrosinase, azo reductase, veratryl alcohol oxidase, riboflavin reductase and dichlorophenolindophenol reductase are known as key biodegrading enzymes which break the complex structures of dyes. Schematic metabolic pathways of degradation of different dyes and their environmental fates have also been proposed. Degradation products of dyes and their fates of metabolism have been reported to be validated by UV-vis spectrophotometry, high performance liquid chromatography, high performance thin layer chromatography, Fourier Transform Infrared Spectroscopy, gas chromatograph-mass spectroscopy and several other analytical tools. Constructed wetlands and various pilots scale reactors were developed independently using the plants of P. australis, Portulaca grandiflora, G. pulchella, Typha domingensis, Pogonatherum crinitum and Alternanthera philoxeroides. The developed phytoreactors gave noteworthy treatments, and significant reductions in biological oxygen demand, chemical oxygen demand, American Dye Manufacturers Institute color removal value, total organic carbon, total dissolved solids, total suspended solids, turbidity and conductivity of the dye effluents after phytoremediation. Metabolites of dyes and effluents have been assayed for phytotoxicity, cytotoxicity, genotoxicity and animal toxicity and were proved to be non/less toxic than untreated compounds. Effective strategies to handle fluctuating dye load and hydraulics for in situ treatment needs scientific attention. Future studies on development of transgenic plants for efficacious phytodegradation of textile dyes should be focused.

Utilization of LPG and gasoline engine exhaust emissions by microalgae

The effect of engine exhaust emissions on air pollution is one of the greatest problems that the world is facing today. The study focused on the effects of realistic levels of engine exhaust emissions of liquid petroleum gas (LPG) and gasoline (GSN) on Phormidium sp. and Chlorella sp. Multi parameters including pH, different medial compositions, fuel types, flow rates and biomass concentrations were described in detail. Effects of some growth factors such as triacontanol (TRIA) and salicylic acid (SA) have also been tested. The maximum biomass concentration of Phormidium sp. reached after 15 days at 0.36 and 0.15 g/L initial biomass concentrations were found as 1.160 g/L for LPG emission treated cultures and 1.331 g/L for GSN emission treated cultures, respectively. The corresponding figures were 1.478 g/L for LPG emission treated cultures and 1.636 g/L for GSN emission treated cultures at 0.65 and 0.36 g/L initial Chlorella sp. biomass concentrations. This study highlights the significance of using Phormidium sp. and Chlorella sp. for utilization of LPG and GSN engine exhaust emissions by the help of growth factors.