Developmental stages: anther

The particular stage of development of the anthers at the time of culture is the most important factor in achieving success in the formation of haploids. In angiosperms with an indeterminate number of anthers in each flower bud, buds can be selected that will contain several anthers in various stages of pollen development. Pollen can be fractionated by pouring them on a percoll gradient. In species with a determinate number of anthers per flower, a series of buds must be examined in order to give all the stages of development. Some easy distinguishable visible traits are used to select later on the most appropriate developmental stage (e.g. petals are just somewhat larger than the sepals; stage 2, figure hereafter).