Chromosome Observation And Karyotype Analysis Of Culinary Rhubarb

Culinary rhubarb (Rheum rhaponticum L.) is a cultivar belong to Polygonaceae, Rheum.. Based on theprevious research work of rhubarb introduction group from Henan Institute of Science and Technology, thispaper studied chromosome observation and karyotype analysis of culinary rhubarb from the existing twovarieties of rhubarb RAMB and RO. Using root tips of seedlings and tissue cultured plantlets, chromosomenumber, karyotype formula, the karyotype, chromosome arm ratio, relative length, index of relative length,karyotype asymmetry coefficient were investigated. The investigations had provided information forculinary rhubarb with cytology, rhubarb chromosomes number and morphological characteristics, includingthe following main findings:(1)The chromosome number of seedling and tissue cultured plantlets from the two cultivars ofculinary rhubarb was stable (2n=44), with a basic number of chromosome being11. The two cultivars ofculinary rhubarb were both tetraploidy.(2)The chromosomes of seedling and tissue cultured plantlets from the two cultivars of culinaryrhubarb mainly contained by center chromosome (m), near center centromere chromosome (sm). Theiraverage arm ratio changed from1.32to1.36.(3)The chromosomes karyotype of seedling and tissue cultured plantlets from the two cultivars ofculinary rhubarb were all “1B” type. The karyotype asymmetry coefficient changed from56%to59%.(4)The chromosomes formula of seedling and tissue cultured plantlets from the two cultivars showeddifference, rhubarb RAMB being2n=44=36m+8sm and RO being2n=44=32m+12sm.(5)The chromosomes of seedling and tissue cultured plantlets from the two cultivars of culinaryrhubarb varied in relative length and coefficient of relative length. Chromosomes from seedling has a lagervariation relative length, RAMB showed chromosome relative length was6.41to1.49, and RO was5.37~12.95. Chromosome relative length from tissue cultured plantlets changed relative smaller, RAMBwas6.82~10.96and RO was6.71~10.76. There were4types of chromosome length observed in seedlings,including long (L), medium long (M2), medium short (M1) and short chromosome(S). But the numbers ofthese4types of chromosomes were different, RAMB was2n=44=4L+16M2+20M1+4S, RO was2n=44=4L+16M2+16M1+8S. Fro tissue cultured plantlets, only3types of chromosomes were observed,including M2, M1and S. The number of different chromosome type was also different, RAMB was2n=44=28M2+12M1+4S, RO was2n=44=24M2+16M1+4S.