In vitro plant regeneration holds great potential in the agriculture and horticulture, especially in crop improvement and hybrid breeding. Moreover, it is also applicable to studies of plant developmental regulatory mechanisms. For in vitro embryogenesis, the most important step is to re-establish the totipotency and further develop into an embryo. Embryo cell fate can be established from different tissue culture. Among the different pathways, we focus on microspore embryogenesis, where haploid embryos arise from stress-induced microspore culture.