Abstract
Melon (Cucumis melo L. group) plants of a resistant line and a susceptible line to viviparous sprouting, known as vivipary, were grown with three different concentrations (6.5, 13, and 26 me·L−1) of nitrate nitrogen in order to clarify the relationship between viviparous sprouting in the fruit and endogenous levels of abscisic acid (ABA). Vivipary increased with the highest nitrate nitrogen treatment in the fruits of the susceptible line. No viviparous sprouting, however, was observed with any nitrogen treatments in the resistant line. Higher nitrate nitrogen treatments decreased the ABA content in juice around the placenta, showing higher content in the resistant line than in the susceptible line. These results suggest that high nitrate nitrogen application decreases ABA content in juice around the placenta and consequently increases in viviparous sprouting, and that the susceptible line has lower content of ABA in juice.
