Efficient protocol for in vitro direct plant regeneration in chickpea Cicer arietinum L.

An efficient plant regeneration system was developed for two important Indian chickpea cultivars, C-235 and HC-1. Immature cotyledons (7-8 mm) directly formed shoots without an intervening callus phase on MS medium containing B5 vitamins, BAP (2.0 mg/l), IBA (0.125 mg/l), AgNO3 (1.69 mg/l) and phytagel (2.5 g/l). The regenerated shoots had normal morphology and were successfully rooted in half strength MS medium under partial dark conditions. Regenerated plants were transferred to potted soil. However, the survival rate of pot house transferred plants was 17.6 per cent.

Interspecific hybridization in Brassica juncea and Brassica tournefortii through embryo rescue and their evaluation for biotic and abiotic stress tolerance.

Interspecific hybrids were obtained in an otherwise incompatible cross Brassica juncea x Brassica tournefortii through in vitro culture of hybrid embryos. The best response was observed from culture of embryos excised 20 days after pollination on MS medium supplemented with kinetin, alpha-naphthylacetic acid, gibberellic acid, glutamine and casein hydrolysate. One hybrid plant had many distinct or intermediate characters. It was tolerant to aphid attack, exhibited irregularities in meiotic events and was partially fertile. The F2 open pollinated and BC1 progenies showed a large diversity in their morphological traits and some promising plants with less aphid infection, drought tolerance and high yield were selected.

Morphological and oil content variation in seeds of Azadirachta indica A. Juss. (Neem) from northern and western provenances of India.

Seed morphology (seed length and 20 seed weight) and oil content was studied in Azadirachta indica A. Juss. (Neem) of five provenances of northern and western India. Trees with wide ranges of girths were considered for study. Maximum average oil content was observed in trees from Hisar provenance. Seed oil content in most of the provenances was not consistently and significantly correlated with morphological parameters of seeds. Age of the tree had no significant effect on the oil yield.

Genotoxic effects of deltamethrin in the mouse bone marrow micronucleus assay.

The genotoxicity of deltamethrin was studied in Swiss albino male mice (five animals/group) using the bone marrow micronucleus assay. Deltamethrin (two i.p. injections, 30 h and 6 h before sample collection) was found to induce micronuclei at 162.5 and 300.0 mg/kg body weight. A lower dose (32.5 mg/kg body weight) failed to induce a significant increase in micronuclei over the control level.

Proline status of genetically stable salt-tolerant Brassica juncea L. somaclones and their parent cv. Prakash.

Three Brassica juncea L. somaclones (SR-1, -2 and -3) selected in vitro for NaCl-tolerance, non-selected somacone (CP-5) and parent cv. 'Prakash' were characterized for their free proline contents in the absence of stress and as a function of increasing salt stress. In the R0 generation, 'SR-3' somaclone had ca. three times higher free proline as compared to parent 'Prakash' and other somaclones. Somaclone, SR-1, turned out to be sterile. The other somaclones were carried forward to the R2 generation after making selections for yield and yield components in the R1 generation. 'SR-3' bred true for its high proline accumulating characteristic. The somaclone 'SR-3' thus had a stable genetic variation for proline overproduction. Free proline content in 7-day-old whole seedlings and 6-week-old plant leaf tissue, increased with the increase in salt stress in all the lines but at differential rates. The magnitude of increase in free proline was much higher in 'SR-3' lines as compared to parent 'Prakash' and 'SR-2' salt-tolerant somaclones. Under salt stress, in leaf tissue, one of the 'SR-3' derived lines (SR3P6-2) accumulated as much as 269 µmoles of free proline as compared to ca. 20 µmoles per g dry weight in parent 'Prakash' and 'SR-2' line. It was interesting to note that there was a 'critical point' concentration of NaCl beyond which the endogenous level of free proline rose sharply. Somaclonal lines (SR3P6-2, SR2P1-2 and CP5-2) which were found to have higher salt-tolerance indices, also had higher 'critical points' as compared to the other relatively salt sensitive genotypes. The relationship between relative water content and osmotic potential of leaves under saltstress also showed a relatively higher degree of osmotic adjustment in the selected somaclones, the maximum being in SR-3 derived lines.

The need for prophylactic antibiotics after female sterilization: tetracycline in Bangladesh.

All female sterilization patients in Bangladesh receive five-day courses of tetracycline capsules every six hours as a postoperative prophylactic. A double-blind randomized study was conducted by the Bangladesh Fertility Research Programme (BFRP) to determine whether prophylactic antibiotics reduced infection after minilaparotomy, and to compare the prophylactic effectiveness of tetracycline and ampicillin. Women recruited from throughout Bangladesh (N = 1350) received five-day courses of 250 mg tetracycline, 250 mg ampicillin, or placebo. The infection rate was significantly lower with tetracycline than with placebo (6% vs 10% with placebo), but did not differ significantly between the ampicillin and placebo groups or between the tetracycline and ampicillin groups.

Salt-tolerance and proline accumulation: a comparative study in salt-tolerant and wild type cultured cells of eggplant.

A NaCl-tolerant cell line of eggplant has been isolated, as a spontaneous variant, on agar solidified medium supplemented with 1% NaCl (Electrical conductivity -17.5 m mho/cm), a concentration lethal to the wild type cells. The stability of the altered response of the selected clone was confirmed by growing it on normal medium for 3 months and then bringing back to the stress medium. This cell line not only grew well on media containing upto 1% NaCl but also required 0.25% NaCl for its optimal growth. It is interesting to note that there is a certain concentration of NaCl (Critical point) above which the proline content of the cells rises sharply. A relationship between the NaCl stress and proline content has been found. The critical point in the wild type cultured cells (0.75% NaCl) lies below to that of the selected salt-tolerant variant (1.0% NaCl).

Comparative electrophoretic studies of proteins and enzymes of some Brassica species.

A considerable amount of variation with respect to soluble proteins and esterase isoenzyme pattern was observed between different species of Brassica. Naturally occurring amphidiploids had comparable proteins and isoenzyme patterns to either one or both of the parental species. The species relationship based on percentage homology of protein and esterase bands revealed that B. nigra and B. campestris are the parental species of B. carinata and not B. nigra and B. oleracea, as suggested on the basis of cytological studies. Elimination of a pair of chromosomes might have resulted into 2n=34 in the case of B. carinata. Further studies are needed to confirm this view. The peroxidase and catalase isoenzyme patterns did not show much variation in different species and amphidiploids.