Differential antioxidative response of tolerant and sensitive maize (Zea mays L.) genotypes to drought stress at reproductive stage.

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes — Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools — glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.

Dermatoglyphic profile in congenital cataracts.

Forty-five children with congenital cataract cases were studied for patterns and compared with age sex matched controls. The patients showed marked differences in different dermatoglyphic traits. The intra uterine aetiological groups i.e. rubella, hereditary and undetected aetiology, showed variations in mainline terminations. Rubella group showed increased angle atd.

Sister chromatid exchanges in congenital cataracts.

A total of 25 patients with bilateral congenital cataracts, from three aetiological groups i.e. rubella (6 patients) hereditary (6 patients) and undetected aetiology (13 patients) were studied for sister chromatid exchanges (SCE). SCEs were markedly raised in the rubella groups as compared with age sex matched controls. The other two groups also showed raised SCE, more so in hereditary group.

Genetic appraisal of congenital cataract.

A total of 45 congenital cataract cases were studied for chromosomal aberrations and dermatoglyphic patterns. Whereas parents showed no marked differences, patients showed marked differences in different dermatoglyphic traits as compared to age-sex matched controls. Out of all the patients Rubella, hereditary and undetected actiology groups showed variations differently, SCE were seen in all cataracts irrespective of their aetiology as compared to controls.

Local anaesthetic activity of some new substituted acylamides II.

Six new substituted acylamides, chemically related to lignocaine were studied for local anaesthetic activity and toxicity in mice, frogs and guinea pigs. Only one of these compounds, w-pyrrolidino 2, 3, 5, 6 tetramethyl acetanilide was found to possess potency comparable to lignocaine with a slightly higher therapeutic index. Study of the S.A.R. of this group indicated that by removal of two methyl groups at position 3 and 5 in the above compound, a local anaesthetic with greater potency than lignocaine may be obtained. Further exploration of the potentialities of a compound having pyrrolidine group as a part of basic side chain is indicated.