ABSTRACT
Seaweeds are aquatic photosynthetic organisms belonging to the domain Eukarya and to kingdoms Plantae and Chromista. Seaweed extracts are known to contain a wide range of bioactive compounds. Several studies have shown that the stimulating effects are due to a variety of major constituents within the seaweed extracts, such as diverse plant nutrients, phytohormones or betaines. Organic matter contained in seaweed biofertilizers is known to stimulate plant growth due to its nutrient content. Furthermore, seaweeds are rich in proteins, fiber, fat, cellulose, hemicelluloses, lignin, vitamins, bromine, and iodine. Yield enhancement effects due to improved chlorophyll content in leaves of various crop plants have been attributed to the betaines present in the seaweed. In particular, seaweed extracts made from different starting raw materials, and by different procedures, are reported to have a number of beneficial effects such as increased nutrient uptake, biotic and abiotic stress tolerances, and improvement in the quality of products.
