Investigations into Causes of Sterility

Abstract

Vicia faba L. plants were treated with three gametocides namely 2, 2 -dichloropropionic acid (Dalapon), sodium 2, 3-dichloroisobutyrate (Mendok) and 1, 2-dihydropyridazine 3, 6-dione (Maleic hydrazide), with an aim of inducing pollen sterility. Various concentrations of these gametocides were applied as aqueous foliar sprays at several stages of plant growth.Of the various applications of these gametocides tried, only 2, 2-dichloropropionic acid at 0.3 per cent and sodium 2, 3-dichloroisobutyrate at 0.25 and 0.4 per cent levels were found to be capable of causing complete pollen abortion. In order to determine the exact stage at which pollen abortion is caused by these gametocides, meiosis was studied in 2, 2-dichloropropionic acid and sodium 2, 3-dichloroisobutyrate-treated plants and their controls. It has been observed that while the former gametocide brings about a variety of meiotic irregularities, latter does not do so. The following pages bear the details of meiosis in untreated and 2, 2-dichloropropionic acid-induced male sterile plants. Material and methods Flower buds from untreated and 0.3 per cent 2, 2-dichloropropionic acid treated plants were harvested and fixed at comparable stages of development in acetic-alcohol (1:3) with acetic acid component saturated with ferric acetate. Following overnight fixation the buds were transferred to 70 per cent alcohol. Pollen mother cells were squashed in 0.5 per cent acetocarmine.All observations and microphotographs were made from temporary preparations, while only a few slides were made permanent for future record, by passing through acetic acid-tertiary-butyl alcohol series. Observations Meiosis in untreated plantsEarly prophase chromosomes consisting of differentially stained segments kept overlapped and were, therefore, not countable. Meiotic chromosomes could, however, be best studied at diakinesis, prometaphase and metaphase stages (Figs. 1, 2). At all these stages, six bivalents with varying number of

Anther and pollen development in male-sterile intermediate wheatgrass plants derived from wheat × wheatgrass hybrids

“…Male sterility has been known to be associated with meiotic disturbances (Novak and Betlach 1970;Jain 1960) and meiotic disturbances with high tempel-atures (Jain 1960;Kaul 1970). Oahe 2 was not investigated meiotically during the period when disturbances were occurring so further associations could not be made between high temperatures during critical periods, meiotic abnormalities, and subsequent sterility.…”