Observation On Morphology And Anatomy Of Microspore Abortion Of Cytoplasmic Male Sterile Line In Kenaf (Hibiscus Cannabinus L.)

Kenaf (Hibiscus cannabinus L.) is a fast growing bast fiber crop of great interest asa source of low cost natural fiber and feedstock for energy production as well.Untilization of hetrosis in kenaf that is more than 30% has been a research hot pot for along time. Since Zhou Ruiyang discovered a cytoplasm male sterile (CMS) mutant inspices UG93 in Hainan province in 2001, CMS line K03A and its maintainer K03B hadbeen selected fistly in 2003, which was highly resistant to anthracnose, and 9 CMS lineshad been selected. To investigate the mechanism of microspores'abortion process andthe classification of CMS lines in kenaf, morphological and cytological studies wereconducted in K03A, L23A, P03A, 917A, 763A, 258A, 722A, B19-1A, and FU3A. Theresults were as follows:1. The CMS lines in kenaf could be divided into dehiscence with trace pollens andnon-dehiscence types on the basis of morphological characters of anthers. According tothe main abortion period, CMS lines were classified into four types, mononuclearmicrospore abortion, binucleate pollen abortion, transitional, and mult-period abortiontypes.2. Anthers in CMS lines were small or withered in faint red, white, or snuff colour. Mostdidn't dehisce and others dehisced with trace poorly developed pollens. Pollens weresmall size, malformation, and with less mulching material on pollen's surface.3. Some densely stained and sickle-shaped microspores which appeared in tetrad stage,developed abnormally and disappeared gradually in mononuclear stage in some CMSlines. At middle and late mononuclear microspore stage, microspores of some CMS linesdisaggregated with protoplasm shrank and degraded into densely stained mass, as well as some gross distorted and degenerated generally. At binucleate pollen stage,plasmolysis and cytoplasm degradation of pollen were observed in some CMS lines.4. Abnormalities were found in taptum as early as-mother microspore stage, whilegenerally vacuolation and cell fusion and protoplasm' inflow into anther chamberappeared in tapetum at mononucleate microspore stage, resulting in breakage or badeffection of microspores' development.5. Analysing the effect of different cell nucleus with the same male sterile cytoplasm, wefound that methods and earliest time of abortion is similar, and the abortion alwayspersisted for a long time, while main abortion period of microspores were different.6. The abortion process of microspores of CMS lines cultivated in nanning in thesummer persisted longer than that cultivated in hainan in the winter, whereas mainabortion period and abortion methods and abnormalities of taptum were similar. It issuggested that sterility of research material is relatively stable.