Cytological and Cytochemical Observation on Microspore Abortion of GMS and CMS in Kenaf (<I>Hibiscus cannabinus</I> L.)

Abstract

Kenaf(Hibiscus cannabinus L.) is a potential alternative crop developed for fiber production,but the utilization of hybrids of the sterile line combination in production was seldom reported.Nuclear male sterile lines were discovered from the maintainer line L23B by Dr.Zhou Ruiyang in 2005,and six cytoplasmic male sterile(CMS) lines including cytoplasmic male sterile(CMS) line L23A were identified in 2007.For exploring the mechanism of male sterility,it is necessary to study the changes of some metabolic materials in the developing anther.Microsporogenesis of cytoplasmic male sterile(CMS) line L23A,together with its maintainer line L23B and genic male sterile(GMS) line L23BS which is a mutant of L23B,was studied by microscopic observation with cytological and cytochemical methods.The results indicated that microspore deformation of cytoplasmic male sterile(CMS) lines L23A occurred at different stages.Some anthers contained degenerated pollen mother cells(PMCs) which might result in empty pollen sac;some PMCs failed to pass meiosis;some microspores could not be released from tetrad successfully;and tapetal cells vacuolated.Cytochemical studies indicated there were a little protein and a few starch grains in the young anthers.During the growth of anther,no protein and less starch were observed.In genic male sterile(GMS) line L23BS,some microspores were unable to escape from tetrad and aborted mainly between tetrad and mononuclear pollen stages.Before then protein and starch deposited as normal which disappeared gradually after tetrad stage.It should be noted that the protein and starch disappeared gradually,but the content of big starch grains in L23BS connective did not changed during its microsporogenesis.