Use of xyloglucan polymers and oligomers, and derivative compounds, as phytosanitary products and biofertilizers

Use of a compound comprising an osidic structure of formula:

• X1-X2-X3-(X4)n
• in which X1, X2, X3, and X4, independently from one another, represent a sugar chosen from glucose, galactose, xylose, fucose, or arabinose, this sugar being optionally in reduced form and/or being substituted, in particular by an alkyl or acyl group, such as a methyl or acetyl group, and n represents 0 or 1,
• X1, X2, X3, and X4, independently from one another, being optionally substituted by one or more sugars chosen from glucose, galactose, xylose, fucose, or arabinose, and/or by one or more osidic chains of formula X5-X6-(X7)m in which X5, X6, and X7, independently from one another, represent a sugar chosen from glucose, galactose, xylose, fucose, or arabinose, and m represents 0 or 1,
• at least one of X1, X2, X3, or X4, or, optionally, of X5, X6, or X7 representing a xylose or a fucose,
• or of a compound derived from those defined above, in particular by modification or substitution of one or more above-mentioned sugars, said compounds and their derivatives having the property:
• of stimulating glutathione reductase,
• and/or of stimulating phospholipase D in plants,
• and/or of stimulating glycosyl hydrolases,
• within the scope of uses linked to the above-mentioned properties of said compounds, namely:
• the adaptation of plants to an abiotic stress, such as adaptation to the cold, or to a hydric stress such as drought, humidity or salinity,
• the control of flowering,
• the control of fructification,
• the induction of defence reactions against pathogens such as bacteria, viruses, fungi.