Want to know about sex? Ask a cucumber. Cucumber flowers can have SEVEN different sexes and preferences – a bit like the LBGT of the plant world. And how does that connect with watching tennis?
Cucumber flowers are usually classified as either male or female and, of course, it’s only the female flowers on your cucumber vine that will develop into fruit.
But it seems that a cucumber flower can look ‘female’ but have some stamens, look ‘male’ but have some carpels, have both sexes present in the one flower, or be a female plant that starts to develop only male flowers, becoming a hermaphrodite. Which is also common in marijuana plants. (Apparently). Cucumber flowers can also have ‘tendencies’ but nothing definite.
It’s the receptors for the hormonal mechanisms that control gender dimorphism that create these many gender types. One hormone affects stamen (male) development, and the other stimulates carpel (female) development, and for a flower to be definitively male or female, there must be a receptor that inhibits the growth of the opposite sex. And different genotypes among cucumber plants have different affinities for these regulating hormones.
High fruit production greenhouses use cucumber plants with only female flowers as they can create the super-rich growing conditions needed to sustain high levels of fruit development per plant. Output per plant is about 15 times more cucumbers then that of plants that carry both male and female flowers. On female-flower only plants, fruit is produced parthenocarpically, so the cucumbers will be seedless.
A new study at the Boyce Thompson Institute at Cornell University in New York has finally found the gene duplication that causes female-only flowers on some cucumber varieties by screening 115 different cucumber lines. This raises more focussed breeding possibilities to increase cucumber production.
High cucumber production is especially important during Wimbledon season in Britain, when the sale of over 450,000 glasses of Pimm’s No1 Cup causes a spike in cucumber consumption.