Abnormal anther development and high sporopollenin synthesis in benzotriazole treated male sterile Helianthus annuus L.

Foliar application of 1.5% benzotriazole induced 100% pollen sterility in H. annuus. Pollen abortion in treated plants was mainly associated with abnormal behaviour of tapetum. A limited number of anther locule showed early degeneration of tapetum followed by disintegration of sporogenous tissues. On the other hand, some locules showed normal development of tapetum at initial stages. However, this tapetum exhibited degenerated and non-functional cell organelles. In both these situations tapetum failed to provide proper nourishment to developing microspores. The ultrastructure of both tapetum and microspores is different from that of control material with irregularities of exine deposition, endopolyploidy of tapetal nuclei and an alteration of organelle composition being correlated with sterility. Pollen grains thus developed were devoid of nucleus and cell organelles and were complete sterile.

Immunotoxicity induced by subacute acephate exposure in white leghorn cockerels.

Acephate (Ace) is an organophosphate foliar spray insecticide of moderate persistence with residual systemic activity of about 10–15 days. This study was designed to evaluate the immunotoxic effect of oral subacute acephate exposure in 125-day old WLH Cockerel chicks for 28 days. The experimental birds were randomly divided into five groups (C1, C2, T1, T2 and T3), each comprising 25 birds. The birds of group C1 were given no treatment and served as control. Group C2 was administered groundnut oil (1ml/kg) and served as control (vehicle). Group T1 was given ALD50/40 (21.3 mg/kg), and Group T2 was put on ALD50/30 (28.4 mg/kg), while group T3 received ALD50/20 (42.6 mg/kg) of acephate suspended in groundnut oil. Experimental birds of all groups were vaccinated with New Castle disease vaccine at day 7. Blood was collected at two-week intervals for evaluation of humoral immune response. Parameters such as TLC, TP, antibody titre against ND vaccine, DNCB dye test, and histopathology of immune organs were studied to evaluate immunotoxicity. The results were statistically compared (p<0.05) with the control. Acephate produced decreased humoral immune response in terms of New Castle disease vaccine antibody titre, total protein, serum globulin, and serum albumin. Cell mediated immune response was checked with 1-chloro 2, 4 dinitrobenzene dye dermal sensitization test, and it did not reveal any significant differences. Lymphoid organs such as thymus, spleen, bursa, and liver were weighed during necropsy for calculation of organ weight: body weight ratio. After 28 days of acephate exposure, organ:body weight ratios of immune organs were significantly reduced except liver:body weight ratio on 14 days of exposure, which was increased in all treatment groups as compared to control groups. Histopathologically, bursa and spleen showed mild depletion of lymphocytes. To further identify the specific type of cell death as apoptotic or necrotic, DNA ladder assay was performed. DNA fragmentation assay detected ladder pattern (180bp) in DNA from hepatocytes and splenocytes of acephate-treated birds. It is concluded that acephate is immunotoxic, and exerts its immunotoxicity through induction of apoptosis and alteration of immunological parameters.

Molluscicidal activity of Punica granatum bark and Canna indica root

The molluscicidal activity of Punica granatum Linn. (Punicaceae) and Canna indica Linn. (Cannaceae) against the snail Lymnaea acuminata was studied. The molluscicidal activity of P. granatum bark and C. indica root was found to be both time and dose dependent. The toxicity of P. granatum bark was more pronounced than that of C. indica. The 24 h LC50 of the column-purified root of C. indica was 6.54 mg/l whereas that of the column-purified bark of P. granatum was 4.39 mg/l. The ethanol extract of P. granatum (24 h LC50: 22.42 mg/l) was more effective than the ethanol extract of C. indica (24 h LC50: 55.65 mg/l) in killing the test animals. P. granatum and C. indica may be used as potent molluscicides since the concentrations used to kill the snails were not toxic for the fish Colisa fasciatus, which shares the same habitat with the snail L. acuminata