Malavika Dadlani

Effect of seed drying on germination behaviour in citrus

Abstract The effect of air- and silica-drying on seed germination and viability, field emergence, seedling growth and water absorption patterns were studied in three Citrus species (C. karna Raf, C. jambheri Lush, C. grandis Osbeck), in Poncirus trifoliata Raf and the hybrid Troyer citrange (P. trifoliata Raf×C. sinensis Osbeck). The study revealed differences in desiccation sensitivity. P. trifoliata Raf. was found most sensitive to seed-drying, while C. grandis Osbeck and C. karna Raf were fairly tolerant. A close correlation was found between the laboratory germination and field emergence. Seed viability scored on the basis of TZ staining was higher but paralleled the germination percentage in laboratory and seedling emergence tests.

Factors influencing leaching of sugars and electrolytes from carrot and okra seeds

Abstract Seeds of carrot (Daucus carota L.) and okra (Abelmoschus esculentus L.) were soaked in water for 1 and 3 h, respectively, to determine the effects of temperature, seed moisture and pH on leaching of sugars and electrolytes from the seeds. With increase in temperature from 10 to 30°C, leaching of sugars and electrolytes increased, while with increase in seed moisture from 3 to 12%, leaching decreased. The leakage of electrolytes from the seeds depended upon the pH, but that of sugars did not. In general, carrot leached more sugars and electrolytes per unit weight at a given condition than okra. The correlation coefficient of germination percentage with percent leaching of water-soluble sugars from carrot seeds was negative and highly significant.

Pollen–pistil interaction in protogyny and self-incompatibility system of Indian mustard (Brassica juncea (L.) Coss.)

Abstract Fluorescence microscopic investigation was made to understand the interaction between developing pistils and pollen of protogynous (Pg) plants and between protogynous and non-protogynous, and cytoplasmic male sterile (CMS) plants following pollination in Brassica juncea. The pollen viability of protogynous plants was confirmed by staining with carmine acetic acid (CAA) and fluorescein diacetate (FDA). The entire process of intra-specific Pg × non-Pg post pollination events, starting from pollen deposition on the surface of the stigma and culminating with the entry of the pollen tube into the embryo sac, was rapid and completed within two days of pollination. Intra-specific crosses of Pg × Pg did not show a single pollen germination on the stigmatic surface and, consequently, no pollen tube growth was observed up to six days after pollination. The pattern of pollen tube growth in crosses between CMS × Pg was essentially similar to that for Pg × non-Pg pollination.