Practice question

Water hyacinth Eichhornia crassipes is free-floating perennial from Amazon basin with spongy petioles providing aerenchyma buoyancy and showy lavender flowers borne on spikes, rendering it attractive for ornamental ponds. British colonial botanical gardens introduced it to Bengal circa 1890 as decorative aquatic. Biology favors invasion: stolons produce clonal rosettes doubling biomass within 6 to 18 days under eutrophic conditions, seeds remain viable decades in sediment, and high evapotranspiration depletes water. Absence of coevolved biocontrol agents like Neochetina eichhorniae weevils allowed unchecked spread across lakes, rivers and irrigation channels, reducing dissolved oxygen, impeding navigation and increasing mosquito breeding habitat. Thus horticultural introduction turned into aggressive ecological weed, now managed under integrated weed management with mechanical removal and biological agents. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs.