Foliar application of salicylic acid improved morpho-anatomical features of potato by irrigating with wastewater.

BACKGROUND: This study aimed to evaluate the suitability of using drain water as a source of irrigation and its effects along with salicylic acid on morphological, anatomical, physico-chemical as well as yield attributes of potato. For this study, potato tubers were grown in pots and irrigated with different concentrations of drain water. Salicylic acid treatments vis. 0, 0.5 and 1.0 mM were applied foliarly. Pre- and post-harvest analysis was carried out to determine different attributes of soil, water and plants after 60 days. RESULTS: The growth of potato plant was increased as the concentration of SA increased through increasing shoot length, fresh/dry weight and tuber number/plant. In this research work, plant respond to overcome metal stresses by up regulating antioxidant defense system such as, peroxidase, catalase and superoxide dismutase) by application of highest treatment of SA when irrigated with 6% drain water. Plants accumulated the highest concentrations of Cd, Cr, and Pb in the leaves when treated with 1 mM of SA, compared to other plant parts. It was observed that photosynthetic pigment enhanced in 6% drain water treated plants when applied with 1mM SA as compared to control. An increase in epidermis and cortical cell thickness, as well as stomatal closure, was observed, helping to maintain water loss under stress conditions. CONCLUSIONS: According to these results, it can be suggested that SA is potent signaling molecule can play an essential role in maintaining potato growth when irrigated with drain water containing heavy metals through stimulating metal up take and up regulation of antioxidant enzymes.

Nano-Integrated Plant Tissue Culture to Increase the Rate of Callus Induction, Growth, and Curcuminoid Production in Curcuma longa.

Turmeric has attracted a significant amount of interest in recent years due to its strong antimicrobial properties. The tissue culture of turmeric is preferred to obtain disease-free, highest number of plantlets with good uniform chemistry. However, there is a need to increase the speed of the whole process to meet the growing demand for planting materials and to save time and resources. Iron oxide nanoparticles (Fe3O4 NPs) showed positive effects on callus initiation time, proliferation rate, percent root response, shoot length, percent rooting, and number of roots per explant. Highest callus induction, i.e., 80%, was recorded in cultures that were grown in the presence of 15 mg/L of Fe3O4 NPs. Callus initiated earlier in culture tubes that received green synthesized iron nanoparticles in a concentration between 10-15 mg/L. Biofabricated nanoparticles were characterized for their size, physiochemical, and optical properties through UV-Vis spectroscopy, FTIR, XRD, and SEM. Curcuminoids profiling was performed by implementing LC-Ms that revealed increased quantities in plantlets grown in nano-supplemented media when compared to the control.

Graphene Oxide Nanoparticle-Assisted Promotion of Stevioside, Rebaudioside A, and Selected Biochemical Attributes in Stevia rebaudiana Bertoni.

Stevia rebaudiana Bert. is commonly known as candy leaf, sugar leaf, or sweet leaf. It is a natural sweetener that has low calories and is used as a substitute for sucrose. The objective of this research is to evaluate the effects of graphene oxide (GO) on the growth, biochemical activities, and stevioside and rebaudioside A production of Stevia in in vitro-raised plantlets. For this, green nanomaterials of GO (0, 2, 4, 6, 8, and 10 mgL-1) were applied to the in vitro plants to enhance its sweetness by triggering the production of stevioside and rebaudioside A and other growth and biochemical parameters. It was observed that all the growth parameters of Stevia plants significantly increased with all GO treatments tested. Total chlorophyll and protein contents were increased (1.85- and 2.65-fold increase from the control) by applying 8 mgL-1 of GO to the MS medium. The maximum value (4 mg·g-1 of protein) of peroxidase activity (POD) was observed by applying 4 mgL-1 of GO, 28.92-fold increase from the control. In comparison, superoxide dismutase activity (SOD) (0.4 mg·g-1 protein) was observed with 10 mgL-1 of GO (1.56-fold increase from the control). Stevioside (12.9 and 8.9 mg·g-1 DW) and rebaudioside A (3.2 and 0.81 mg·g-1 DW) were observed only at 6 and 8 mg·L-1 treatment of graphene oxide. According to the findings, using graphene oxide (GO) had a significant impact on the growth, biochemical activities, and steviol glycoside production in Stevia. This shows that GO has the potential to be a valuable enhancer of sweetness and overall Stevia leaf quality, providing great prospects for the development of low-calorie natural sweeteners.

Growth-Promoting Endophytic Fungus (Stemphylium lycopersici) Ameliorates Salt Stress Tolerance in Maize by Balancing Ionic and Metabolic Status.

Climate change is a major cause of the world's food security problems, and soil salinity is a severe hazard for a variety of crops. The exploitation of endophytic fungi that are known to have a positive association with plant roots is preferred for improving plant growth, yield, and overall performance under salt stress. The current study thus rationalized to address how salt stress affected the growth, biochemical properties, antioxidant capacity, endogenous indole-3-acetic acid (IAA), and the ionic status of maize associated with endophytic fungus (Stemphylium lycopersici). According to the findings, salt stress reduced chlorophyll a and b, total chlorophyll, total protein, sugars, lipids, and endogenous IAA levels. Enhanced values of chlorophyll a/b ratio, carotenoids, secondary metabolites (phenol, flavonoids, and tannins), antioxidant enzyme activity (catalase, ascorbate peroxidase), proline, and lipid peroxidation were noticed in maize plants under salt stress. Increased ionic content of Na+, Cl-, Na+/K+, and Na+/Ca2+ ratio, as well as decreased Ca2+, K+, Mg2+, N, and P contents, were also found in salt-stressed maize plants. In comparison to the non-saline medium, endophytic association promoted the antioxidant enzyme activities (798.7 U/g protein; catalase activity, 106 U/g protein; ascorbate peroxidase activity), IAA content (3.47 mg/g FW), and phenolics and flavonoids (88 and 1.68 µg/g FW, respectively), and decreased MDA content (0.016 nmol/g FW), Na+ ion content (18 mg/g dry weight), Cl- ion (16.6 mg/g dry weight), and Na+/K+ (0.78) and Na+/Ca2+ (1.79) ratios, in maize plants under salt stress, whereas Ca2+, K+, Mg2+, N, and P contents were increased in maize plants associated with S. lycopersici under salt stress. Current research exposed the role of S. lycopersici as an effective natural salt stress reducer and maize growth promoter; hence, it can be used as a biofertilizer to ameliorate salt stress tolerance in crops along with better growth performance in saline regions.

Fulvic Acid Alleviates Paper Sludge Toxicity in Canola (Brassica napus L.) by Reducing Cr, Cd, and Pb Uptake.

Heavy metal toxicity reduces the growth and development of crop plants growing in metal-contaminated regions. Disposal of industrial waste in agricultural areas has negative effects on the physiochemical activities of plants. This research aimed to examine the fulvic acid (FA)-mediated efficacy of Brassica napus L. regarding stress tolerance in soil amended with paper sludge (PS). For this purpose, plants were grown for 90 days under greenhouse conditions at various concentrations of PS-amended soils (0, 5, 10, and 15%) being irrigated with water containing FA (0, 10, and 20%). All the physicochemical parameters of PS were carried out before and after plant transplantation. Paper sludge toxicity reduced the growth (shoot/root length, fresh/dry weight of shoot/root, numbers of flowers and leaves) and physicochemical characteristics of exposed B. napus plants. In comparison, FA application improved growth by reducing the metal uptake in the shoot of plants grown at various concentrations of PS. An increasing trend in antioxidant enzyme activity was observed by increasing the FA concentration (0%-10% and 20%). Post-harvest analysis indicated that the amount of tested metals was significantly reduced at all PS concentrations. Minimum metal uptake was observed at 0% concentration and maximum at 15% concentration of paper sludge. Additionally, FA application at 20% concentration reduced Chromium (Cr), Cadmium (Cd), and Lead (Pb) uptake in the shoot from 6.08, 34.42, and 20.6 mgkg-1 to 3.62, 17.33, and 15.22 mgkg-1, respectively. At this concentration of paper sludge in the root, 20% FA reduced Cr, Cd, and Pb uptake from 11.19, 44.11, and 35.5 mgkg-1 to 7.88, 27.01, and 24.02 mgkg-1, respectively. Thus, FA at 20% concentration was found to be an effective stimulant to mitigate the metal stress in B. napus grown in paper sludge-polluted soil by reducing metal uptake and translocation to various plant parts.

ACC deaminase-producing endophytic fungal consortia promotes drought stress tolerance in M.oleifera by mitigating ethylene and H2O2.

Introduction: Drought has become more prevalent due to dramatic climate change worldwide. Consequently, the most compatible fungal communities collaborate to boost plant development and ecophysiological responses under environmental constraints. However, little is known about the specific interactions between non-host plants and endophytic fungal symbionts that produce growth-promoting and stress-alleviating hormones during water deficits. Methods: The current research was rationalized and aimed at exploring the influence of the newly isolated, drought-resistant, ACC deaminase enzyme-producing endophytic fungi Trichoderma gamsii (TP), Fusarium proliferatum (TR), and its consortium (TP+TR) from a xerophytic plant Carthamus oxycantha L. on Moringa oleifera L. grown under water deficit induced by PEG-8000 (8% osmoticum solution). Results: The current findings revealed that the co-inoculation promoted a significant enhancement in growth traits such as dry weight (217%), fresh weight (123%), root length (65%), shoot length (53%), carotenoids (87%), and chlorophyll content (76%) in comparison to control plants under water deficit. Total soluble sugars (0.56%), proteins (132%), lipids (43%), flavonoids (52%), phenols (34%), proline (55%), GA3 (86%), IAA (35%), AsA (170%), SA (87%), were also induced, while H2O2 (-45%), ABA (-60%) and ACC level (-77%) was decreased by co-inoculation of TP and TR in M. oleifera plants, compared with the non-inoculated plants under water deficit. The co-inoculum (TP+TR) also induced the antioxidant potential and enzyme activities POX (325%), CAT activity (166%), and AsA (21%), along with a lesser decrease (-2%) in water potential in M. oleifera plants with co-inoculation under water deficit compared with non-inoculated control. The molecular analysis for gene expression unraveled the reduced expression of ethylene biosynthesis and signaling-related genes up to an optimal level, with an induction of antioxidant enzymatic genes by endophytic co-inoculation in M. oleifera plants under water deficit, suggesting their role in drought stress tolerance as an essential regulatory function. Conclusion: The finding may alert scientists to consider the impacts of optimal reduction of ethylene and induction of antioxidant potential on drought stress tolerance in M. oleifera. Hence, the present study supports the use of compatible endophytic fungi to build a bipartite mutualistic symbiosis in M. oleifera non-host plants to mitigate the negative impacts of water scarcity in arid regions throughout the world.