Meiotic Abnormalities in Populations of Heracleum lanatum Michx. -An Endemic and Threatened Medicinal Plant from Lahaul & Spiti Cold Desert Region of North Indian Higher Altitude Himalayas

摘要

Heracleum lanatum Michx. also known as Cow parsnip, is an important medicinal plant belonging to the family Apiaceae. At present, chromosome number and meiotic behavior analysis has been carried out in 6 wild populations of Heracleum lanatum from different study areas such as Keylong, Udaipur, Trilokinath, Batal, Losar and Kaza of Lahaul & Spiti (Cold Desert) region of the North Indian higher altitude Himalayas. Morphologically, all these populations do not show any noticeable differences. All the presently worked out populations are diploid (2n=22) showing a base number of x=11. The meiotic course in all the populations is found to be abnormal, beside with normal bivalents, stickiness of bivalents, presence of bridges and laggards during anaphases and telophases, cytomixis involving more than 2 PMCs at A-I, A-II, T-I and T-II. The chromatin transfer phenomenon among the pollen mother cells (PMCs) in 6 populations caused various meiotic abnormalities. Hence this phenomenon of cytomixis seems to be directly under genetic control and it affects the meiotic course and is directly responsible for abnormal meiotic behavior. Besides abnormal meiotic course the microsporogenesis was found to be normal. No significant correlation was found between cytomixis and pollen fertility, however some cytomictic plants showed low values with 79.56-89.40% of pollen fertility.