Modification of sex expression in sponge gourd (Luffa cylindrica L.) roem by mineral nutrient treatments

Effects of three major mineral nutrient elements, nitrogen, phosphorous and potassium, on sex expression in Luffa cylindrica (L.) Roem were investigated in relation to nodal location of the first male and the first female flower on the plant as well as the ratio of the male-female flowers, otherwise known as sex ratio.Potassium-containing nutrient treatments (K, NK & PK) reduced the mean node number of the first staminate inflorescence but did not change the mean node number of the first pistillate flower. These treatments promoted staminate flowering and caused a shift towards maleness while nitrogen- and phosphorous-containing nutrient treatments (N, P, NP & NPK) promoted pistillate flowering and reduced staminate flowering, causing a shift towards femaleness. These results are explained in terms of hormonal balance in the plant. The possible role of mineral nutrients in hormonal balance and thereby in sex expression is discussed.