Comparison of in vitro seeds and shoot tips colchicine treatment methods on of Thymus daenensisCelak via the study of morphological features of stomata and cellular DNA content

Colchicine treatment for the inductive polyploidy on different parts of the plant can affect the results. The aim of present study was to compare the influence of colchicine treatment on seeds and shoot tips of thymus daenensisplants. Examination of stomatals morphological features and analyze of cellular DNA content by spectrophotometry is an indirect ways but faster and cheaper to determine ploidy level in plants. To achieve this objective، seeds and shoot tips were treated in diffrentcolchicine concentration levels including (0. 0%، 0. 03%، 0. 05%، 0. 08%، 0. 1% w/v) for 24 and 48 hours and the survival rate of seeds and shoot tips were estimated. The effect of colchicine was measured by the number of chloroplasts in stomatal guard cells، the density of stomata on the leaf surface and cellular DNA content. Significant decline was seen in both treatment in comparison to the control group but survival rate was significantly higher in shoot tips treatment than seeds. In seed treatment، frequency of chloroplasts and total DNA content varied significantly in 0. 08% colchicine application for 24 hours and significant decrease were found in stomatal density at this concentration. Similar result was seen in shoot tip treatment at the concentration of 0. 03% and 0. 1% for 48 and 24 hours but only significant change was seen in frequency of chloroplasts. In conclusion، plant،s section that use for colchicine treatment can affect the results، and despite of reduction of seedssurvival rate under colchicine treatment، seeds treatmentat the level of 0. 08% (w/v) for 24 hours in comparison to the shoot tips treatment is a better way to induce polyploidy.