ABERRANT MICROSPOROGENESIS AND STERILITY IN IMPATIENS SULTANI (BALSAMINACEAE)

Three mutants of Impatiens sultani (named as ‘Orange', ‘Crimson', and ‘Pink') show an unusually wide spectrum of aberrations in microsporogenesis. These aberrations range from premeiotic cytomixis to meiotic and postmeiotic irregularities such as precocious disjunction, tripolar separation of chromosomes, chromosome bridges, various patterns of atypical cytokinesis, supernumerary divisions of the meiotic products, and irregular divisions in the microspore. As a result of these abnormalities Orange is partially and Crimson and Pink are completely pollen sterile. The stigmas of Pink, besides, do not support pollen germination. The failure of pollen germination is attributed to the defective stigmatic fluid of Pink, which, compared to that of Orange and Crimson lacks organic compounds absorbing UV light at 261 nm. This constitutive deficiency in stigmatic fluid appears to be a little investigated facet of female sterility.