Fusion of male gamete with diploid secondary nucleus produces ___ and it is known as ___(respectively).
In Cucurbita, pollen tube enters the ovule through the integuments.
After the pollen tube enters the embryosac, its apex dissolves and the male gametes are liberated. One of the male gametes fuses with the egg and produces a diploid zygote (Strassburger, 1884) which by further division develops into an embryo. The other male gamete fuses with the diploid secondary nucleus (fusion product of two polar nuclei) and produces a triploid (3n) primary endosperm nucleus (Nawaschin, 1898). This is called double fertilization.
Thus, there are three fusions occur in the embryo sac.1. The fusion of two polar nuclei to form secondary nucleus
2. The fusion of one male gamete with the egg.3. The fusion of another male gamete with the secondary nucleus to form primary endosperm nucleus(PEN). Hence, the process is called triple fusion.