Highlights•Fermented organic materials and their hydrolysates were tested on substrate-grown Hibiscus.•Positive effects were observed on total biomass, plant height, SPAD index and net photosynthesis compared with untreated plants.•Tested products performed at the same level of a commercial product.•Obtained results represent a step forward for the application of biowaste hydrolysates in intensive substrate cultures. AbstractTwo urban biowaste materials, fermented under anaerobic and aerobic conditions, their soluble and insoluble alkaline hydrolysates, and a commercial biostimulant product, were compared for their capacity to boost Hibiscus crop production and quality. Plants were grown in 4-litre pots, containing peat and pumice as substrate, under optimal growing conditions. A randomized-block experimental design was adopted. Two types (main factors of variability) of treatments were applied, i.e. by blending the above products with the substrate at transplant, and by fertigation using the soluble hydrolysates only. Plant biomass characteristics and ecophysiological parameters were measured. Mean effect of factors and their interactions were assessed by two-way ANOVA. Principal component analysis was performed by using the different dependent variables to summarize the most relevant differences among treatments. Compared with the control (untreated plants), the applied treatments enhanced most of the investigated parameters. The most valuable effects were observed for total biomass accumulation (+25%), plant height (+10%), leaf chlorophyll SPAD index (+15%) and net photosynthesis (+24%). The hydrolysates performed better than the pristine materials. The former ones were comparable to the commercial biostimulant. The results confirmed the hypothesis that biowaste derived products induce biostimulant activity on Hibiscus; their application can improve cultivation sustainability. ); SD, soluble digestate hydrolysate obtained from the alkaline hydrolysis of D; SGC, soluble compost hydrolysate obtained from the alkaline hydrolysis of GC; SUB, treatments applied to the substrate as a powder blended with the substrate; T 1 , beginning of the experimentation (30 days after transplant) (day)

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Biostimulants are substances promoting plant growth, quality and stress resistance.The present work aimed to investigate whether soluble hydrolysates from biowaste performed as biostimulants. Hibiscus (Hibiscus moscheutos L. subsp. palustris) plants were subjected to four treatments: standard fertilization, low fertilization, and low fertilization with added soluble digestate or soluble compost. Plant performance indicators were biomass accumulation, biometric parameters, leaf gaseous exchanges and elemental composition, and nitrogen-use efficiency. Low fertilization negatively affected most of the investigated parameters. However, plants treated with biowaste-derived products performed better than untreated low-fertilized plants (+21 to 145 % for biomass accumulation and biometric parameters, and carbon assimilation rate) and for many parameters reached values comparable to those showed by standard-fertilized plants or even higher, as in the case of K, Si, and Mo leaf content, and N use efficiency. Therefore, the tested soluble hydrolysates demonstrated to have biostimulant properties in hibiscus grown under nutritional stress.

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In common parlance, succulents are all fleshy plants with swollen stems and leaves. Instead, it would be more correct to use the term succulent, as their characteristic feature is that they have succulent tissue inside them, i.e. a soft, spongy fleshiness saturated with water that produces a typical swelling in the plant. Usually, the swelling of the plant is in the aerial parts, i.e. the stem and leaves. There are, however, some cases of succulence at the roots and intermediate variants with succulence distributed in the leaves, stem and roots simultaneously. These plants represent a world apart in terms of their characteristics, resistance, vegetative behaviour, flowering and many other features. In this review, we would like to describe some aspects of these plants that make them as strange as they are extraordinary.

The aim of the experiment was to evaluate the use of effective micro-organisms (EM) as promoters of root development and germination of K. daigremontiana plants. The 3 experimental groups in cultivation were: 1) group without microorganisms (CTRL), irrigated with water and previously fertilised substrate; 2) group with sugar cane molasses (ML) and fertilised substrate; 3) group with effective micro-organisms (EM) and fertilised substrate. The test showed a significant increase in the agronomic parameters analysed in plants treated with effective micro-organisms. In fact, all plants treated with (EM) showed a significant increase in plant height, number of leaves, vegetative and radical weight, number and weight of new shoots, leaf area. Also regarding the physiological analysis of plants there is a significant increase in the parameters analyzed in the thesis with effective micro-organisms. In particular, there was a significant increase in the chlorophyll content, in leaf net photosynthesis rate (Pn) and water use efficiency (WUE) and an equally significant reduction in transpiration (TR) and stomatological conductance (Gs). In the thesis treated with EM, the experiment also showed an increase in the percentage of seed germination and a significant reduction in the average germination time. Effective micro-organisms can be a valuable tool for grafting before planting new plants, for spraying and irrigation of crops, for reducing or eliminating completely the use of plant protection products against pathogens and diseases, during the storage of plant raw materials and to increase the biological activity of the soil.