Wolffia globosa, also known as Asian watermeal or Mankai, is the world’s smallest flowering plant. This aquatic plant floats on the surface of freshwater bodies, appearing as tiny green specks. Its characteristics draw attention for its potential as a sustainable resource. It offers rapid growth and a rich nutritional profile, making it a subject of increasing scientific and culinary interest.
What is Wolffia Globosa
Wolffia globosa is classified within the Lemnaceae family, known as duckweeds, which are small, free-floating aquatic plants. Each plant, or frond, is an oval structure, measuring between 0.1 to 0.2 millimeters in diameter, comparable to a pinhead or pepper flake. Unlike most plants, Wolffia globosa lacks distinct roots, stems, or leaves, instead consisting of a simplified green frond that absorbs nutrients directly from the water.
This species is native to Southeast Asia but has established populations across various continents, including North and South America, Africa, and Oceania. It thrives in calm, freshwater environments such as ponds, lakes, and marshes, often forming dense mats on the water’s surface, demonstrating its adaptability.
Nutritional Powerhouse
Wolffia globosa is recognized for its nutritional composition, often referred to as a “superfood.” Its dry weight can contain 20-45% protein, surpassing many common plant-based protein sources like soybeans and lentils. This protein includes all nine essential amino acids, with a profile comparable to egg protein.
Wolffia globosa is also a source of omega-3 fatty acids, particularly alpha-linolenic acid (ALA), which constitutes approximately 1.2% of its dry weight. The plant provides vitamins, including beta-carotene (Vitamin A), B vitamins such as thiamine (B1), riboflavin (B2), niacin (B3), and vitamin B12, which is rare in plant sources. Its mineral content includes iron (15-20mg per 100g dry weight), calcium (400-500mg per 100g), and magnesium (250-300mg per 100g), alongside trace minerals like zinc, selenium, and manganese. It also contains antioxidants and polyphenols, such as quercetin and rutin.
Ecological and Practical Applications
Beyond its direct use as a human food source, Wolffia globosa offers ecological and practical applications. Its high protein content and rapid growth rate make it a promising sustainable food source for both human consumption and livestock feed. In regions like northern Thailand, it is a popular ingredient in traditional cuisine.
The plant also shows promise in bioremediation efforts, absorbing excess nutrients and pollutants from water bodies, improving water quality. Its ability to rapidly produce biomass makes it a subject of research for biofuel production, including its potential as a biocatalyst in plant-based biofuel cells.
Cultivation and Growth
Wolffia globosa reproduces through asexual budding, where daughter fronds break off from the parent plant and grow independently. This rapid vegetative reproduction allows for a quick doubling of its biomass within 2 to 3 days under optimal conditions. It thrives in still or slow-moving freshwater environments, preferring a water pH between 5 and 7.
Successful cultivation requires specific environmental conditions. The plant benefits from well-lit areas, often requiring several hours of direct sunlight daily. Maintaining water temperatures between 21-30°C (70-86°F) also supports optimal growth. For large-scale cultivation, nutrient-rich water is used to support its rapid growth.