R. B. Singh

Effect of insecticides on germination, early growth and cytogenetic behavior of barley (Hordeum vulgare)

Abstract Seeds of barley ( Hordeum vulgare L. cv. “Ratna”) were treated for 3 hr with 0.1% solutions of the active ingredients of commercial formulas of six systemic (Dimecron, Citrolane, Thimet, Counter, Furadon and Disyston) and three nonsystemic (Endrin, Cythion and Ambithion) insecticides, and ethylmethane sulphonate (EMS). In general, insecticide treatments did not reduce germination (except for Ambithion), but did reduce seedling height, pollen fertility and chiasma frequency. Different cytological aberrations, viz. , chromosome fragments at mitotic metaphase; chromatin bridges, fragments, laggards, bridges with fragments and/or laggards at mitotic anaphase; univalents, precocious separation and nonorientation of bivalents at meiotic metaphase I; and laggards, bridges, bridges with laggards, tripolar divisions and unequal separation of chromosomes at anaphase I, were observed in the treated populations in frequencies significantly higher than those in the control. Some insecticides induced significantly greater cytological aberrations and other detrimental effects, such as reduction in germination, seedling height and pollen fertility, than EMS.

Effect of buffer and pH on growth and protein content of carrot (Daucus carota L.) in liquid shake culture

Phosphate, succinate, acetate and maleate buffers were tested for buffering B5 liquid medium. Phosphate (0·02 M) and acetate (0·002 M) were the most suitable buffers as they promoted dry weight accumulation and nitrogen assimilation, they also exhibited less change in pH after 5 days cultivation of carrot cells. The pH increase from 5·5 up to 6·5 also increased the dry weight accumulation and cell size; pH 7·0 was detrimental to dry weight accumulation.