Persistence of Callose and Tapetum in the Microsporogenesis of Genic Male Sterile Cajanus cajan (L.) Millsp. with Well Formed Endothecium.

Abstract

In genic male sterility (GMS) the breakdown of microsporogenesis is mediated by dominant genes as well as by multiple recessive genes (Gottschalk and Kaul 1974, Albertsen and Palmer 1979). When compared to cytoplasmic male sterile plants (Laser and Lersten 1972, Hegde and Isaacs 1992), only a few reports are available on the cytology and microsporogenesis of genic male sterile plants. Cheng et al. (1979) found that vacuolation and cytoplasmic disintegration of tapetal cells precede the pollen abortion in GMS Zea mays. Albertsen and Palmer (1979) in Glycine max, and Takahashi (1986) in Houttuynia cordata attributed pollen abortion to failure of cytokinesis and formation of coenocytic microspores. Failure of callose breakdown resulting in the non-separation of tetrads was thought to be responsible for sterility in the GMS Cajanus cajan (Reddy et al. 1978). In contrast, Dundas et al. (1981) reported early degeneration of the tapetum as a cause for sterility in B-15-B version GMS Cajanus cajan. Sawhney and Bhadula (1988) suggested that low esterase activity caused the delay in the tapetal degeneration and failure of exine formation in male sterile stamenless-2 mutant of Lycopersicon esculentum. In this plant, effect of temperature, mediated through endogenous IAA and Polyamines, was also implicated as responsible for male sterility (Rastogi and Sawhney 1990a, b, Singh et al. 1992). Shukla and Sawhney (1992) suggested the possible involvement of cytokinins in the expression of sterility in GMS Brassica napus. In male sterile mutant of Oenothera absence of ektexine sporopollenin precursors was considered responsible for male sterility (de Halac et al. 1990). Association of tapetal hypertrophy with sterility was observed in some mutants of barley (Singh and Kaul 1990, 1991). The diversity in the cytological and morphological characters in different sterile lines of Cajanus cajan (Reddy et al. 1978, Dundas et al. 1981) suggests that the sterility is conditioned by different genes which have different physiological effects. Therefore, there is still a scope to investigate types of sterility expression in other male sterile sources of GMS Cajanus cajan to test the hypotheses already proposed. The present study compares microsporogenesis in the fertile line Cajanus cajan with its GMS (ms Prabhat) counterpart, at the light microscope level. Materials and methods Cajanus cajan (L.) Millsp. (ms Prabhat) seeds were obtained from International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Hyderabad, India. Plants were raised in the Karnatak University Botanical garden. The male-sterile plants were identified by their pale yellow shrivelled anthers. Flowers from fertile and sterile plants were fixed for two hours in * To whom correspondence .

MS32 -regulated timing of callose degradation during microsporogenesis in Arabidopsis is associated with the accumulation of stacked rough ER in tapetal cells

“…The dissolution of callose is equally important, since in male-sterile mutants with persistent callose abnormalities in pollen development ensue, e.g. in pepper (Horner and Rogers 1974), soybean Palmer 1985, 1987), Brassica napus (Theis and Röbbelen 1990) and Cajanus cajan (Katti et al 1994).…”

Cytological Investigations of the Microsporogenesis in Male-sterile Ramie (Boehmeria nivea Gaud.) and Its Offspring

“…In ramie, the degenerative process observed in microsporogenesis of male-sterile plants began at the tetrad stage with the thickness and persistence of the callose surrounding the tetrads which hindered microspore release up to after they collapsed. There are some possible explanations to the persistence of thickened callose in ramie tetrads such as an abnormal form of callose (b-1,3-glucan) that impairs callase enzyme action, or a defective form of callase enzyme (b-1,3-glucanase) produced by tapetum tissue that was unable to attach and break callose wall and set the microspores free, as reported in Cajanus cajan, by Katti et al (1994), or a low level of callase production that was not enough to break callose wall, or the failure in reducing the pH of the anther locule, what is essential to callase action just after pollen mother cells entered the tetrad stage as reported by Jin et al (1997). There are also examples of male sterility associated to tapetal cell abnormalities and callose wall persistence (Shivanna and Johri 1989).…”

An overview of male-sterility systems in pigeonpea [Cajanus cajan (L.) Millsp.]

“…Histological studies by Katti et al (1994) showed differences between male-sterile and male-fertile pigeonpea lines. Pre-meiotic development was identical in anthers of both lines.…”