Prajitha V, Thoppil J E
Cell and Molecular Biology Division, Department of Botany, University of Calicut, Kerala, 673635, India.
Cytotechnology. 2018 Feb;70(1):95-101. doi: 10.1007/s10616-017-0100-9. Epub 2017 May 5.
The present study is aimed to identify genetic variability between two species of Amaranthus viz., A. caudatus and A. hybridus subsp. cruentus, two economically important species, cultivated mainly for grain production. Karyomorphological studies in Amaranthus are scarce, probably due to higher number of small sized chromosomes. Karyomorphological studies were conducted using mitotic squash preparation of young healthy root tips. Karyological parameters and karyotypic formula were established using various software programs and tabulated the karyomorphometric and asymmetry indices viz., Disparity index, Variation coefficient, Total forma percentage, Karyotype asymmetry index, Syi index, Rec index, Interchromosomal and Intrachromosomal asymmetry index and Degree of asymmetry of karyotypes. The mitotic chromosome number observed for A. caudatus was 2n = 32 with a gametic number n = 16 and A. hybridus subsp. cruentus was 2n = 34 with a gametic number n = 17. In A. caudatus the chromosome length during somatic metaphase ranged from 0.8698 to 1.7722 μm with a total length of 39.1412 μm. In A. hybridus subsp. cruentus the length of chromosome ranged from 0.7756 to 1.9421 μm with a total length of 44.9922 μm. Various karyomorphometry and asymmetry indices analyzed revealed the extend of interspecific variation and their evolutionary status.
本研究旨在确定两种苋属植物之间的遗传变异性，即尾穗苋和红叶苋亚种，这是两种经济上重要的物种，主要用于粮食生产。苋属植物的核形态学研究很少，可能是因为小染色体数量较多。使用幼嫩健康根尖的有丝分裂压片制备进行核形态学研究。使用各种软件程序建立核型参数和核型公式，并将核形态测量和不对称指数制成表格，即差异指数、变异系数、总形态百分比、核型不对称指数、Syi指数、Rec指数、染色体间和染色体内不对称指数以及核型不对称程度。观察到尾穗苋的有丝分裂染色体数为2n = 32，配子数n = 16，红叶苋亚种的有丝分裂染色体数为2n = 34，配子数n = 17。在尾穗苋中，体细胞中期的染色体长度范围为0.8698至1.7722μm，总长度为39.1412μm。在红叶苋亚种中，染色体长度范围为0.7756至1.9421μm，总长度为44.9922μm。分析的各种核形态测量和不对称指数揭示了种间变异的程度及其进化状态。
