A Comparison of Anther Tissue Development in Male Sterile Aloe vera and Male Fertile Aloe ciliaris

Cytological differences between the anther development of amale sterile and a male fertile Aloe species are used to explaininteractions between anther tissues. Some deviations in thelayers of the locule wall and the microspores of the male sterileanther are related to each other and their biological functionsare discussed. The cytological development of the male sterility,which can be observed shortly after meiosis, seems to be restrictedto the locular cavity. The tapetal development and breakdownare normal, apart from the size of some orbicules. However,the pollenkitt is not transported to the pollengrains, whichstrongly supports our theory that this process is mechanicallypollen-controlled. The development of the epidermal and endothecialcells is normal, except in a part of the anthers where thesecells do not expand, after which dehiscence is incomplete. Thelatter process is discussed in relation to the deviations insidethe locular cavity. Aloe vera (L.) Burm. fil., Aloe ciliaris Haw., Liliaceae, male sterility, tapetum, pollenkitt, endothecium, anther dehiscence