Brown juice is a byproduct of fractionated green biomass during leaf protein isolation. It represents approximately 45%–50% of the total pressed fresh biomass. Disposal of brown juice is a serious issue in leaf protein production due to its high biological oxygen demand and carbohydrates content. The current study aimed to find a possible potential use of brown juice. Therefore, chemical and biochemical properties of brown juice—derived from alfalfa green biomass—were determined before and after fermentation by lactic acid bacteria. Additionally, the growth stimulation potential of fermented brown juice on plumed cockscomb (Celosia argantea var. plumose ‘Arrabona’) plants were tested. Celosia seedlings were sprayed at different rates of fermented brown juice (i.e., 0.5%, 1%, 2.5%, 5%, and 10%) and tap water was applied as control. The results revealed that lactic acid bacteria successfully enhanced the stabilization of brown juice via reducing sugars content and increasing organic acids content. After fermentation, contents of glucose monomers were 15 times lower; while concentrations of lactic and acetic acids increased by 7- and 10-fold, respectively. This caused a reduction in the pH of fermented brown juice by 13.9%. Treating Celosia plants at lower rates of fermented brown juice (up to 1.0%) significantly induced their growth dynamics and antioxidant capacity. Higher values of vegetative parameters were measured in treated plants compared to control. The brown juice treatments caused significant changes in histological parameters as well. The activity of catalase and peroxidase increased in plants that received fermented brown juice especially at low rates. Moreover, an increase in water-soluble protein and phenol was measured in different tissues of plants sprayed with fermented brown juice. Malondialdehyde content was lowered in treated plants compared to control. Fermented brown juice at high rates slightly reduced the amount of photosynthetic pigments; however, this reduction was not reported for low rates of fermented brown juice. These results surely illustrate the potential use of fermented alfalfa brown juice as a growth stimulator for crops particularly at rates below 2.5%.

The biostimulant segment is becoming increasingly important worldwide. One of the reasons for this is that fewer plant protection products are placed on the market in the European Union, and environmental sustainability also plays an important role in their use. Biostimulants are often used in several horticultural sectors, including ornamentals, to strengthen plants, achieve commercial standards, produce quality goods, increase plant vitality, and aid harvesting. This paper presents the latest results of the use of biostimulants in horticulture, with special emphasis on ornamental plant production. The legal regulation of biostimulants and their regulatory mechanisms are described in detail in the review. The main groups of biostimulants are also discussed. The response of plants to abiotic stress, in particular physiological, anatomical, and genetic changes, with regard to the application of biostimulants is also detailed. Focus is given to the areas of ornamental crop production, such as sexual and asexual propagation, cultivation, and harvesting, where biostimulants are used.

Fertilization management is a key issue in plant nutrition to produce plants with good quality and quantity. Deproteinized leaf juice or brown juice (BJ) is a by-product during the isolation of leaf protein from biomass crops such as alfalfa. The idea of using BJ as a biostimulant fits well in the aspect of circular economy since BJ is currently a problematic issue of the leaf protein production approach. Fractionation of one-kilogram fresh biomass results in approximately 500 cm3 BJ. Due to fast spoil of fresh BJ, if left on room temperature, it is found that fermentation of fresh BJ using lactic acid bacteria and reducing its pH increases its stability and storage on room temperature. In the present study, we examined the effect of fermented alfalfa BJ on vegetative, physiological, and anatomical properties of the versatile sweet basil (Ocimum basilicum L. ‘Bíborfelhő’) plants. Sweet basil seedlings were sprayed at different doses of fermented alfalfa BJ (i.e., 0.5%, 1.0%, and 2.5%) and tap water served as a control (0.0% BJ). The results revealed that foliar application of fermented alfalfa BJ significantly improved the biometrical features of sweet basil plants. Plants treated with fermented BJ showed significantly higher values of all the measured parameters compared to the control (0.0%), except for the number of leaves per plants where control plants (0.0%) had more leaves. However, the leaves of control plants (0.0%) were smaller than treated plants as data of leaf area showed. Fermented alfalfa BJ significantly increased the content of photosynthetic pigments (chl a and chl b), relative chlorophyll (SPAD value), lengths of stem and root, fresh masses of stem, root, and leaves, volumes of stem and root, and leaf area. Despite all rates of fermented BJ displayed higher values over control plants (0.0%), the rate of 0.5% was the best one supported by results. Application of fermented alfalfa BJ influenced the anatomical parameters as well. These findings demonstrate the possible use of fermented alfalfa BJ as a promising novel plant biostimulant.

Glyphosate is still the subject of much debate, as several studies report its effects on the environment. Sunflower (GK Milia CL) was set up as an experimental plant and treated with glyphosate concentrations of 500 ppm and 1000 ppm in two treatments. Glyphosate was found to be absorbed from the soil into the plant organism through the roots, which was also detectable in the leaf and root. Glyphosate was also significantly detected in the plant 5 weeks after treatment and in plants that did not receive glyphosate treatment directly, so it could be taken up through the soil. Based on the morphological results, treatment with higher concentrations (1000 ppm) of glyphosate increased the dried mass and resulted in shorter, thicker roots. Histological results also showed that basal and transporter tissue distortions were observed in the glyphosate-treated plants compared to the control group. Cells were distorted with increasing concentration, vacuoles formed, and the cell wall was weakened in both the leaf-treated and inter-row-treated groups. In the future, it will be worth exploring alternative agricultural technologies that can reduce the risk of glyphosate while increasing economic outcomes. This may make the use of glyphosate more environmentally conscious.

Organic and ecological farming programs require new and efficient biostimulants with beneficial properties for the sustainable and safe production of seedlings and ornamental plants. We examined the effect of non-fermented and lacto-fermented alfalfa brown juice (BJ) on seed germination and the vegetative, physiological, and anatomical properties of French marigold (Tagetes patula L. ‘Csemő’) plants which were treated with 0.5–10% fermented and non-fermented BJ, with tap water applied as a control. Applying 0.5% fermented BJ significantly improved seed germination compared with non-fermented BJ, resulting in an increase of 9.6, 11.2, 10.9, and 41.7% in the final germination percent, germination rate index, germination index, and vigor index, respectively. In addition, it increased the root and shoot length by 7.9 and 16.1%, respectively, root and shoot dry mass by 20 and 47.6%, respectively, and the number of leaves by 28.8% compared to the control. Furthermore, an increase in contents of water-soluble phenol, chlorophyll a and b, and carotenoid was reported upon the application of 0.5% fermented BJ, while peroxidase activity decreased. Our results prove that alfalfa BJ can be enrolled as a biostimulant as part of the circular farming approach which supports the sustainable horticultural practice.

In this study the 5-amino-levulic acid containing Pentakeep-V nano-fertilizer was examined in 0.3 ml/l, 0.5 ml/l and 0.7 ml/l concentrations with irrigating or spraying treatment on Begonia x tuberhybrida 'Nonstop' seedling production. The experiment was conducted in Zajzon, in a 300 m 2 heated plastic tunnel, from January 2012 to June 2012. Best result was obtained with 0.5 ml/l concentration in the case of all examined parameters. Pentakeep-V had positive effect in all examined concentrations with both ways of treatments on all measured parameters instead of plant height. The plant growing time was shortened thanking to the treatments. Using additional artificial light plants developed more and bigger flowers. Spraying was more effective comparing to irrigation. All the treatments had positive effect on chlorophyll content in the leaves. Summarizing Pentakeep-V nano-fertilizer can be offered in 0.5 ml/l concentration with spraying treatment in the seedling production of Begonia x tuberhybrida 'Nonstop'. Additional light enhances the effect in most examined parameters that is needed in the general practice during short day growing period.

Plant growth-promoting bacteria (PGPB) and other living organisms can help with the challenges of modern agriculture. PGPB offer ever-expanding possibilities for science and commerce, and the scientific results have been very advanced in recent years. In our current work, we collected the scientific results of recent years and the opinions of experts on the subject. Opinions and results on soil–plant relations, as well as the importance of PGPB and the latest related experiences, are important topics of our review work, which highlights the scientific results of the last 3–4 years. Overall, it can be concluded from all these observations that the bacteria that promote plant development are becoming more and more important in agriculture almost all over the world, thus, promoting more sustainable and environmentally conscious agricultural production and avoiding the use of artificial fertilizers and chemicals. Since many mechanisms of action, namely biochemical and operational processes, are still under investigation, a new emerging scientific direction is expected in the coming years with regard to PGPB, microbial, and other plant growth-stimulating substances, in which omics and microbial modulation also play a leading role.

Several recent studies have shown that glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), resist rapid degradation and, therefore, can accumulate in plants. Continuing our previous research, we aimed to investigate the effect of indirectly spraying glyphosate on leaves and soil on non-target plants in the case of Helianthus annuus L. The plants were treated with glyphosate in their 5–6 leaf stages, the effects of which were assessed two weeks later from a morphological and histological point of view, as an evaluation of the residues of glyphosate and its metabolite, AMPA. They had an effect on both treated groups. In the case of the morphological parameters (plant height, number of leaves, and fresh and dried root and green mass), the data of the treated plants were statistically lower than in the case of the control group. The epidermis and the transport tissue system were damaged, and tissue death was observed in plants exposed to glyphosate. Both compounds were detected in all plant parts (roots, stems, lower leaves, and upper leaves), well above the limit of detection (0.025 mg/kg) and limit of quantitation 0.075 mg/kg showing a statistical difference with the control plants. This proved that glyphosate is incorporated into the plant organism even when applied indirectly.