Browsing by Author "A.N. Sahi"

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Cytogenetic response of hexavalent chromium-induced somatic cell abnormalities in Allium cepa
(1998) A.N. Sahi; S.K. Singh; P.K. Sen; R.N. Singh
Hexavalent chromium present in water inhibited root growth due to its toxicity and its accumulation in roots. The Cr (VI) concentration in water samples ranged from 0.003 to 0.750 mg/l in and around the Sukinda valley, which was higher than the Government permissible limit. The Cr (VI)-containing water was utilized by local inhabitants for drinking and agricultural practices which produced increases in human health hazards and mutations or cell death in plants. The cytological effect of hexavalent Cr was investigated using onion roots grown in chromium contaminated water samples. The most pronounced chromosome aberration(s) encountered was stickiness followed by bridges with or without fragments, chromosomes with inactivated centromeres, variations of C-mitosis, vagrant chromosomes and micronuclei. The presence of C-mitosis appeared to be due to complete inhibition of spindle fibres. Mitotic chromosomal abnormalities were more numerous and death to the cell occurred at higher concentrations. Local inhabitants were advised not to drink the Cr-contaminated water nor to eat below ground plant parts.
Cytomorphological Studies of Spontaneous and Artificial Triploids and Their Role in the Evolution of Hexaploid Solanum nigrum L.
(1992) R.N. Singh; A.N. Sahi; D.N. Tiwari
[No abstract available]
Fly-ash induced chromosomal aberrations in Allium cepa
(1996) A.N. Sahi; R.N. Singh
Fly-ash released from coal-based power plants contains heavy metals which cause genetic damage to, or death of, plants. For genetic investigation onion bulbs were grown in fly-ash polluted soils, collected around such a power plant. Root growth was checked in all soil samples after 72 h when their tips were turning brown or black. Mitotic and chromosomal anomalies, viz clumping stickimetaphase, laggards, chromatin bridges and fragments were encountered. Abnormalities were more numerous nearer the source of the pollution. Fragments and c-mitosis appeared but in lower numbers due to heavy metal inhibition of spindle fibres. Deposition of fly-ash contaminates the soil, upsets equilibrium of the ecosystem, and causes genetic damage to flora in and around power plants.
Induction of chromosome aberrations and chlorophyll mutations in plants by methylisocyanate (MIC) gas
(Birkhäuser-Verlag, 1990) G. Kumar; A.N. Sahi; S.K. Roy
Seeds of Solanum surattense Burm. f. collected from areas of Bhopal (India) affected by methylisocyanate gas showed chromosome aberrations in root cells, and growth retardation and chlorophyll mutation of seedlings, the frequencies of which varied from one locality to another. © 1990 Birkhäuser Verlag Basel.
Meiotic Studies of Induced Auto-octoploid Spironetna fragrans Lindle
(1992) R.N. Singh; A.N. Sahi
[No abstract available]
Studies on induced auto-octoploid and its implication in the origin of tetraploid Solarium villosum of the Solarium nigrum complex
(1997) R.N. Singh; A.N. Sahi
Auto-octoploidy as confirmed from a somatic chromosome count of 2n = 96 was induced for the first time in Solarium vlllosum, a member of the Solanum nigrum complex. Chromosome doubling helped in assessing the origin/evolution of the tetraploid S. villosum. The average meiotic configuration was 3.80 I + 43.30 II + 0.40 III and 1.10 IV against 24 bivalents in the control. Meiotic abnormalities consisted of laggards, bridges, unequal separation and polysporads all of which adversely affected pollen fertility. The presence of tetravalents and meiotic abnormalities in the octoploid confirmed the natural tetraploid origin of S. villosum and the true genome donor was untraceable or disappeared at an early stage of evolution.