The relationship of endogenous plant hormones to embryo abortion in fewer-seed watermelon

In order to explore the possible mechanism of embryo abortion in fewer-seed watermelon, three watermelon (Citrullus lanatus) genotypes, F-011, M-05 and their hybrid F-1 generation were used to examine their endogenous hormonal change patterns. Indole-3-acetic acid (IAA), gibberellins (GA(3)), abscisic acid (ABA) and isopentenyladenine (iPAs) in fruit of watermelon plants were measured by indirect enzyme linked immunosorbent assay (ELISA). Results showed that in comparison with its parents, F1 (the seedless genotype) had abnormal variation for the three hormones. IAA, GA3 and iPAs levels in F1 dropped 30%-70% during the globular stage whereas the content of ABA was twice that of F-011 and M-05. Ratios of IAA/ABA, ABA/GA3, ABA/iPAs among the three were also different. It was proposed that the dynamic change patterns of endogenous hormones are closely related to embryonic development and the balance between them is important.