Chlorella vulgaris improves growth of Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta and reduces root attack by nematodes

Abstract

Research objective: The aim of this study is to investigate the effects of Chlorella extract as a biofertiliser on the growth of Abrometiella spp. seedlings and to assess whether it has a repellent effect against nematodes Materials and Methods: The experiments, which began in November 2024, were conducted in the CREA-OF greenhouses in Pescia (PT), Tuscany, Italy (43°54′N 10°41′E) on Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta. The plants were placed in ø12 cm pots; 30 plants per thesis, divided into 3 replicates of 10 plants each. The experimental groups were: i) group without algae, irrigated with water and previously fertilised substrate; ii) group with Chlorella vulgaris, previously fertilised substrate. On 2 April 2024, plant height, leaves number, vegetative weight, root weight, root lenght, number of new plantlets, chlorophyll content, leaf area, control of the nematodes Meloidogyne javanica and Meloidogyne incognita were measured. Results and Discussion: The experiment showed that the use of Chlorella vulgaris extracts can improve the vegetative and root growth of Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta plants grown in pots. The treatment also led to an increase in plant height, number of leaves, length of root hairs, leaf area and number of new seedlings. The trial also showed that the use of Chlorella in plant growing media can also increase the photosynthesis rate (SPAD index) and significantly reduce the presence of nematodes, in particular Meloidogyne javanica and Meloidogyne incognita. According to some researchers, the influence of Chlorella extract on cell metabolisms is mainly due to the physiological effect of major and minor nutrients, amino acids, vitamins, and plant growth regulators on cellular metabolisms in treated plants, which increase crop yields and growth. Chlorella plants have very high photosynthesis rates, dozens of times higher than other plants. The main reason why Chlorella can grow rapidly is because it contains Chlorella Growth Factor (CGF), which is quite rich in nucleoproteins, nucleic acids, ribonucleic acids (RNA), deoxyribonucleic acids (DNA), vitamins, amino acids, polysaccharides, complex protein bodies, enzymes, glycoproteins, plant hormones, etc. Its ability to promote plant growth may be due to this factor. Conclusions: Chlorella extract significantly increased Abrometiella seedling height, leaf number and leaf area. In particular, Abrometiella seedlings treated with chlorella extract developed better root system, chlorophyll a increased significantly and the root length and number of new seedlings also improved significantly. Based on the above results that Chlorella extracts contribute to the growth and development of Abrometiella plants, we can conclude that with the treatment of Chlorella extracts, the application of chemical fertilisers in the production of succulents such as Abrometiella can be reduced.