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Chromosome form and function, including chromosome pairing and separation during meiosis, are under genetic control (Rees 1961). Chromosomes during meiosis generally pair and recombine in the first prophase, followed by normal disjunction of homologous partners in the first anaphase, leading to formation of fertile gametes. Exception to this general phenomenon has been observed in many crop plants. In certain cases due to the homozygous recessive condition of certain genes, chromosomes fail to pair either completely or partially resulting in abnormal meiosis. Such a situation results either in partial or complete sterility in plants depending upon the extent of pairing failure. This failure of chromosomes to pair is referred to as 'asynapsis' or 'desynapsis' depending upon the stage at which pairing fails to occur. The term asynapsis refers to a condition where no pairing is observed at any time in the meiotic cycle. On the other hand, desynaptic plants show normal pairing during early meiosis particularly at pachytene and diplotene, but desynapse at the diakinesis stage. The meiotic behaviour of an induced asynap tic mutant of finger millet (Eleusine coracana) is described for the first time. Materials and methodsEleusine coracana, commonly known as finger millet is one of the important millet crops of South India. In our experiments to induce mutations in this crop, several varieties were treated with different concentrations of ethyl methane sulpho nate (EMS). In one cultivar, Co. 1., seeds were soaked in a 1.5 percent aqueous solution of EMS for eight hours and plants were raised. In the M2 generation, segregation for a number of highly sterile plants in one of the M2 families was observed. The cytological studies revealed the asynaptic chromosomal behaviour in these sterile plants.To study meiosis, flower buds of appropriate size were fixed in acetic alcohol(1:3) and anther smear preparations stained with one percent acetocarmine were prepared. Nature of pairing during different stages of meiosis was studied. Pollen sterility in those mutants was determined by acetocarmine stainability test. ResultsMeiosis in asynaptic mutants: Cytological analysis of early prophase, parti

Hierarchical mesoporous NiO nanoflakes (NiOs) have been synthesized in high yield via a simple, economical and environmentally friendly hydrothermal route. The as-prepared NiOs were characterized by powder X-ray diffraction (PXRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction patterns (SAED), X-ray energy dispersive spectroscopy (EDS) and nitrogen adsorptiondesorption techniques (Brunauer-Emmett-Teller, BET). Adsorption of heavy metal ions onto the as-prepared sample from aqueous solutions was investigated using differential pulse anodic stripping voltametry (DPASV) technique and discussed. The product possesses a BET surface area of 69.27 m 2 g −1 . It is found that NiOs exhibited the excellent performance for the removal of Hg(II), Pb(II) and Cd(II) from aqueous solution. The equilibrium adsorption data of Hg(II), Pb(II) and Cd(II) on the as-prepared NiOs were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of Hg(II), Pb(II) andCd(II) were determined using the Langmuir equation and found to be 1324.5, 1428.9 and 1428.5 mg g −1 , respectively. Adsorption kinetics of all the metal ions followed pseudo second-order model. Moreover, NiOs can be recycled by simple acid treatment, which could retain the high removal efficiency in three successive cycles. This study suggests that nanoflakes could be explored as a new adsorbent with high efficiency and recyclability for removing heavy metal ions from aqueous solution.

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