What are the disadvantages of cleistogamous flowers?

Cleistogamous flowers are self-pollinating flowers that never open, which presents several significant disadvantages. The primary drawback is the complete absence of genetic variation since these flowers can only self-fertilize, leading to inbreeding and reduced genetic diversity within populations. This lack of cross-pollination prevents the introduction of new genetic combinations that could help the species adapt to changing environmental conditions or resist diseases. Additionally, cleistogamous flowers cannot benefit from pollinator services, limiting their reproductive options. The continuous self-fertilization can lead to inbreeding depression over time, where harmful recessive alleles accumulate in the population, potentially reducing overall fitness, vigor, and survival rates of offspring.