Abstract
Humic acids have been widely used for centuries to enhance plant growth and productivity. The beneficial effects of humic acids have been attributed to different functional groups and ...phytohormone-like compounds enclosed in macrostructure. However, the mechanisms underlying the plant growth-promoting effects of humic acids are only partially understood. We hypothesize that the bio-stimulatory effect of humic acids is mainly due to the modulation of innate pathways of auxin and cytokinin biosynthesis in treated plants. A physiological investigation along with molecular characterization was carried out to understand the mechanism of bio-stimulatory effects of humic acid. A gene expression analysis was performed for the genes involved in auxin and cytokinin biosynthesis pathways in wheat seedlings. Furthermore, Arabidopsis thaliana transgenic lines generated by fusing the auxin-responsive DR5 and cytokinin-responsive ARR5 promoter to ß-glucuronidase (GUS) reporter were used to study the GUS expression analysis in humic acid treated seedlings. This study demonstrates that humic acid treatment improved the shoot and root growth of wheat seedlings. The expression of several genes involved in auxin (Tryptophan Aminotransferase of Arabidopsis and Gretchen Hagen 3.2) and cytokinin (Lonely Guy3) biosynthesis pathways were up-regulated in humic acid-treated seedlings compared to the control. Furthermore, GUS expression analysis showed that bioactive compounds of humic acid stimulate endogenous auxin and cytokinin-like activities. This study is the first report in which using ARR5:GUS lines we demonstrate the biostimulants activity of humic acid.
Humic acids are well known for their bio-stimulatory effects on improving plant growth and development. These beneficial effects of humic acids have been attributed to different biological functional groups and other bioactive compounds that are entrapped in their molecular structure. In this study, we demonstrate that humic acid, which is rich in hydroxyl (–OH) and carbonyl (–C=O) functional groups, improves wheat plant growth and development by eliciting the auxin and cytokinin signaling pathways.
Salinity is one of the environmental factors inhibiting productivity in crop plants. Available strategies to mitigate the abiotic stresses are limited. Microalgae and cyanobacteria can mitigate the ...adverse effects of abiotic stress due to their biostimulant properties. The aim of this work was to study the effect of hydrolysate of the ciyanobacterium
Arthrospira platensis
on the growth of
Petunia
plants under salt stress conditions over two growing seasons (winter and spring). Plants were exposed to 2.0, 2.5, and 3.0 dS m
−1
EC, with and without application of
A. platensis
hydrolysate. At the end of the trial, biometric parameters and plant analysis were determined. Petunias had a negative response when the salinity level rose from 2 to 3 dS m
−1
and exhibited moderate tolerance to high internal Na and Cl concentrations. Results show that a high salinity reduces the Ca, Mg, K, and S contents in the leaves and provokes a sharp reduction in the K
+
/Na
+
relationship. Applying
A. platensis
hydrolysate alleviates the effects of NaCl stress and stimulates shoot and bud formation in the petunia mother plant while inducing flowering in commercial
Petunia
plants. The
A. platensis
hydrolysate application increased the K
+
/Na
+
relationship in treatments with an EC of 3.0 dS m
−1
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The aim of our study was to establish the effect of selenium and betaine on the growth of D. salina, accumulation of photosynthetic pigments and antioxidant activity of the hydrophobic fraction. This ...approach was an attempt to demonstrate 'microalgae biostimulant' effects, similar to 'plant biostimulant' effects, i.e. increased tolerance to abiotic stress and enhanced accumulation of bioactive compounds. A high-throughput assay was done in 24-well microplates, at 15% NaCl and different concentrations of sodium selenite (0, 0.5, 2 and 8 µM) or betaine (0, 5, 50 and 500 µM). Both selenium and betaine induced a slight delay in algae growth during the actively growing stage but the final density reached similar values to the control. Betaine significantly enhanced (50%-100%) carotenoids and chlorophyll a accumulation, in a concentration depending manner. Antioxidant activity increased almost 3-fold in extracts of algae treated with 50 µM betaine. Selenium had a much more discrete effect than betaine on pigments biosynthesis. The antioxidant activity of the extracts increased 2-fold in the presence of Se compared to the control. Our work proves that it is possible to enhance production and activity of bioactive compounds from microalgae by using ingredients, which already proved to act as plant biostimulants.
Context: One oftoday´s challenges is to provide food to all inhabitants, taking into account the growth of global population, especially into the cities. Accordingly, the urban farming systems are ...important, as they offer a real solution in face of the people’s demands. Objective: To compare different bioorganic nutritional alternatives and their influence on growth and yield indicators in carrots (Daucus carota var. sativa). Methods: This research was done at Ernesto Che Guevara intensive green garden (UEB No. 2), from the Agricultural Company of Esmeralda municipality, between December 2016 and March 2017, on non-gley plastic dark soil with high fertility. A completely randomized experimental design was applied, with five treatments and three replicas, the indicators evaluated were plant height, root length, and yield. Results: The best agronomic indicators were achieved in the treatments based on fortified liquid humus enriched with boron, calcium, and zinc, which did not differ among them, but were different from the natural liquid humus, and the control. The fortified liquid humus produced the highest yields and the best economic results. Conclusions: A favorable response was observed to bioorganic alternatives in terms of plant growth and yields. The fortified liquid humus had the best economic effect, with a remarkable increase in revenues, compared to the control.
Malaxis acuminata
D. Don =
Crepidium acuminatum
(D. Don) Szlach. is an important medicinal orchid used in various pharmaceutical preparations including “
Ayurveda
”. We report an improvised ...regeneration protocol for this prized orchid species using transverse thin cell layer (
t
-TCL) explants. The highest rate of shoot proliferation was recorded in the medium supplemented with
meta
-Topolin (
m
T) and chitosan at concentrations of 1.5 mg/l and 5.0 mg/l, respectively, wherein an average of 21 micro-shoots/explant were produced. The micro-shoots were transferred to rooting medium containing auxin indole-3-butyric acid (IBA)/indole-3-acetic acid (IAA) and phenolic elicitor phloroglucinol (PG). The best rooting frequency was observed using 1.5 mg/l IBA and 5.0 mg/l PG in the culture medium. The regenerated plants with proliferated roots and shoots were acclimatized and survival rate was recorded. To evaluate the phytomedicinal efficiency of the micropropagated plants, flavonoid and phenolic compositions were determined using ultra performance liquid chromatography (UPLC). Four prominent fractions of metabolites were detected, of which the highest contents of quercetin and syringic acid were found in pseudobulbs and protocorm-like bodies (PLBs). Also, the highest antioxidant activities were recorded in the pseudobulb followed by PLB, leaf and whole plant extracts. The principal component analysis depicted the association between the plant organs/tissues and their metabolite contents. Furthermore, the expression levels of the five key modulator genes viz.
chalcone synthase
(
chs)
;
phenylalanine ammonia lyase
(
pal
);
cinnamoyl-CoA reductase
(
ccr
);
hydroxymethylglutaryl-CoA-reductase
(
hmgr
) and
diphosphomevalonate decarboxylase
(
mvdd
) belonging to the flavonoid and phenolic acid biosynthetic pathways were studied in order to map the transcript abundance in various tissue parts of
M. acuminata
through quantitative real-time polymerase chain reaction (RT-
q
PCR). The present protocol can serve as a model approach for sustainable utilization of endangered orchid species of high industrial demand, strengthening the utility of chitosan as growth promoter in orchid micropropagation.
Key message
The research reports the use of
meta
-Topolin (
m
T)- chitosan synergy depicting gene-metabolite relation with the scope of adapting it as a model approach for bioprospection and conservation of orchids.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The field experiment was carried out in 2015–2017 on a family farm in Toczyski Czortki, in the Mazovia voivodeship in Poland. The experiment was set up in a split–split–plot system in three ...replications. The area of one plot was 30 m−2. The studied factors were: I—two maize varieties: PR38N86 (medium late hybrid cultivar 280 FAO), P8400 (medium early hybrid cultivar 240 FAO); II—four doses of nitrogen fertilization: 1. control object—without the use of nitrogen (0 kg N·ha−1), 2. nitrogen dose—80 kg N·ha−1 (applied once before sowing), 3. nitrogen dose—120 kg N·ha−1 (applied once before sowing), 4. nitrogen dose—160 kg N·ha−1 (applied once before sowing); III—four types of biostimulants used: 1. control object—without using a biostimulant, 2. Asahi®SL biostimulant: I term—four-leaf phase (BBCH 14) at a dose of 0.60 dm3∙ha−1, II term—eight-leaf phase (BBCH 18) at a dose of 0.60 dm3∙ha−1, 3. Improver® biostimulant: I term—four-leaf phase (BBCH 14) at a dose of 1.00 dm3∙ha−1, II term—eight-leaf phase (BBCH 18) at a dose of 0.60 dm3∙ha−1, 4. Zeal® biostimulant: I term—six-leaf phase (BBCH 16) at a dose of 2.00 dm3∙ha−1. The aim of the study was to determine the effect of nitrogen fertilization and the use of biostimulants on the size and quality of yield of two varieties of maize grown for grain. Based on the conducted research, it was found that nitrogen doses influenced the amount of maize grain obtained. The highest yields were obtained using 120 kg N∙ha−1. Nitrogen doses significantly affected the studied maize yield components. The dose of 120 kg N∙ha−1 increased the number of grains in the cob, while the dose—160 kg N∙ha−1 exerted the best effect on obtaining the highest values of a thousand seeds. The biostimulants used in the experiment significantly affected the mass of one thousand seeds and the number of grains in the cob. In addition, Asahi®SL, Improver® and Zeal® biostimulants increased maize yield in each growing season studied.
Cleome gynandra
L. is used as a vegetable that forms a significant part of the local diet in South Africa and other tropical and subtropical parts of the world.
Cleome gynandra
seeds are negatively ...photoblastic (light-induced dormancy) and fail to germinate when planted immediately after harvest. To enhance better cultivation practices, seed germination of
C. gynandra
using different light wavelengths (red, far-red, green and blue light) with and without organic biostimulants smoke–water (SW), karrikinolide (KAR
1
), Kelpak
®
(KEL) and eckol (ECK) was tested. Among all the tested biostimulants, the best germination percentage (40%) was observed in seeds treated with SW in the dark. However, the biostimulants did not show any significant effect with the light treatments. In this study, blue light generally promoted (≤ 35%) and red light inhibited (≤ 8%) germination. Furthermore, the effect of different biostimulants (under blue and red light) on biochemical content and enzyme activities was tested in seeds of
C. gynandra
. Seeds treated with biostimulants in blue light showed an overall increase in protein and total carbohydrate content in comparison to seeds subjected to biostimulants in red light. The α-amylase activity in the seeds was highest in KEL-treated seeds in blue light. Superoxide dismutase and catalase activity was generally higher in blue-light treatment, while peroxidase activity was highest in red light. Enhanced germination under blue light and inhibitory effects with red light is an intriguing phenomenon for
C. gynandra
seeds, which needs more detailed investigation. The study also indicates the potential application of organic biostimulants (particularly SW) for better seed germination and growth of
C. gynandra
which can be explored by farmers in the field.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Globally, drought stress poses a significant threat to crop productivity. Improving the drought tolerance of crops with microbial biostimulants is a sustainable strategy to meet a growing ...population's demands. This research aimed to elucidate microbial biostimulants' (Plant Growth Promoting Rhizobacteria) role in alleviating drought stress in oil-seed crops. In total, 15 bacterial isolates were selected for drought tolerance and screened for plant growth-promoting (PGP) attributes like phosphate solubilization and production of indole-3-acetic acid, siderophore, hydrogen cyanide, ammonia, and exopolysaccharide. This research describes two PGPR strains: Acinetobacter calcoaceticus AC06 and Bacillus amyloliquefaciens BA01. The present study demonstrated that these strains (AC06 and BA01) produced abundant osmolytes under osmotic stress, including proline (2.21 and 1.75 µg ml
), salicylic acid (18.59 and 14.21 µg ml
), trehalose (28.35 and 22.74 µg mg
FW) and glycine betaine (11.35 and 7.74 mg g
) respectively. AC06 and BA01 strains were further evaluated for their multifunctional performance by inoculating in Arachis hypogaea L. (Groundnut) under mild and severe drought regimes (60 and 40% Field Capacity). Inoculation with microbial biostimulants displayed distinct osmotic-adjustment abilities of the groundnut, such as growth parameters, plant biomass, photosynthetic pigments, relative water content, proline, and soluble sugar in respective to control during drought. On the other hand, plant sensitivity indexes such as electrolyte leakage and malondialdehyde (MDA) contents were decreased as well as cooperatively conferred plant drought tolerance by induced alterations in stress indicators such as catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD). Thus, Acinetobacter sp. AC06 and Bacillus sp. BA01 can be considered as osmolyte producing microbial biostimulants to simultaneously induce osmotic tolerance and metabolic changes in groundnuts under drought stress.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
AbstractThe surge in demand for ornamental crops necessitates a more efficient and accurate fertilization regimen, attributed to their high nutritional requirements and vigorous growth. However, ...there is limited research exploring the response of Epipremnum aureum on Foliar-applied amino acid biostimulants, which can potentially improve the growth and antioxidant properties of these Epipremnum aureum. To address this gap, an indoor pot experiment was conducted, encompassing six treatments that varied in the concentration of applied amino acid biostimulants: 0.00% (T0), 0.04% (T1), 0.06% (T2), 0.08% (T3), 0.10% (T4), and 0.20% (T5). The results showed that the 0.08% concentration significantly increased peroxidase activity by 72.76%. Moreover, the 0.10% concentration increased chlorophyll content, catalase activity, dry mass, and total antioxidant capacity by 44.41%, 69.55%, 2.04-fold and 3.38-fold, respectively. Additionally, the 0.20% concentration significantly increased soluble sugar content by 52.32%. In conclusion, leaf-applied amino acid biostimulants significantly improved the yield and quality of Epipremnum aureum, with the optimal application concentration being 0.10%. These amino acid biostimulants, serving as efficient and non-toxic fertilizers, exhibit promising prospects for widespread application in agricultural production.
Saffron (Crocus sativus L.) is cultivated worldwide. Its stigmas represent the highest-priced spice and contain bioactive compounds beneficial for human health. Saffron cultivation commonly occurs in ...open field, and spice yield can vary greatly, from 0.15 to 1.5 g m−2, based on several agronomic and climatic factors. In this study, we evaluated saffron cultivation in soilless systems, where plants can benefit from a wealth of nutrients without competition with pathogens or stresses related to nutrient-soil interaction. In addition, as plant nutrient and water uptake can be enhanced by the symbiosis with arbuscular mycorrhizal fungi (AMF), we also tested two inocula: a single species (Rhizophagus intraradices) or a mixture of R. intraradices and Funneliformis mosseae. After one cultivation cycle, we evaluated the spice yield, quality (ISO category), antioxidant activity, and bioactive compound contents of saffron produced in soilless systems and the effect of the applied AMF inocula. Spice yield in soilless systems (0.55 g m−2) was on average with that produced in open field, while presented a superior content of several health-promoting compounds, such as polyphenols, anthocyanins, vitamin C, and elevated antioxidant activity. The AMF symbiosis with saffron roots was verified by light and transmission electron microscopy. Inoculated corms showed larger replacement corms (+50% ca.). Corms inoculated with R. intraradices performed better than those inoculated with the mix in terms of spice quality (+90% ca.) and antioxidant activity (+88% ca.). Conversely, the mixture of R. intraradices and F. mosseae increased the polyphenol content (+343% ca.). Thus, soilless systems appeared as an effective alternative cultivation strategy for the production of high quality saffron. Further benefits can be obtained by the application of targeted AMF-based biostimulants.
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