Comparative Studies on Diploid and Tetraploid Levels of Nicotiana alata

Abstract

Abstract: The present investigation was planned to induce polyploid plants of Nicotiana alata by treating seeds in an aqueous solution of colchicine and identify the ploidy level by counting the chromosome number. Compare between diploid and tetraploid plants for some phenotype characters and the mineral content of nitrogen (N) and phosphorus (P) in the different parts of the plant was carried out. Results indicated that colchicine treatments of Nicotiana alata seeds were very effective for producing a large number of tetraploid plants. Chromosome number of tetraploid plants was determined and was confirmed by microscopic observations in both mitotic and meiotic divisions. Morphologically, tetraploid plants showed an increase in the vegetative and flowering characters than the diploid plants with new ornamental characteristics. The increase in the rate of N and P nutrients in both diploid and tetraploid plants of Nicotiana alata caused an obvious increase in their content in different parts of the plant. In addition, the mineral content in root, stem and leaves recorded higher values in the tetraploid plants than in the diploid ones. It was concluded that morphological characters and mineral contents (N and P) in colchitetraploid plants were very obviously changes than in diploid plants. Key words: Nicotiana alata Colchicine Diploid Tetraploid Mineral content