Cytomorphological Study of Trigonella disperma (Fabaceae) in Iran

Abstract

Summary Chromosome number, meiotic behaviour and morphological characters related to habit and pollen grains were studied in 8 populations of Trigonella disperma of Trigonella sect. Ellipticae native to Iran. All populations are diploid and possess a chromosome number of 2n=2x=16, which is consistent with the proposed base number of x=8. This taxon displayed regular bivalent pairing and chromosome segregation at meiosis. However, some meiotic abnormalities observed included varied degrees of sticky chromosomes with laggards and bridges in metaphase I or II, asynchronous nuclei in metaphase II, desynapsis in metaphase I, and cytomixis. This paper reports the first known study of the meiotic chromosome number and behaviour of T. disperma. We evaluated and determined the population limits within T. disperma, employing multivariate statistics. Results from meiotic behaviour supports the phenetic grouping. We found a striking association between morphological patterns of the pollen grains, meiotic behaviour and habit morphology. Our results showed that Iranian populations of T. disperma represent the same chromosome, suggesting that the pollen size in different populations can be served to obtain useful information. The environment of origin seems to have an effect on the chromosomes within different populations.

Meiotic behavior of B chromosome in two species of <i>Trigonella</i> L. from Bangladesh

“…Thus tri-polarity and disturbed polarity could be found due to un-oriented spindle apparatus which may lead to producing unbalanced and sterile gametes. Moreover, failure of chromosome movement occurred in one of the poles of anaphase cells, leading to the formation of tri-polar cells (Ranjbar et al 2011). Chromosome breakage and vagrant chromosome (Grewal and Rani 2019) might be due to the clumping of chromosomes and clumping might occur as a consequence of the stickiness of chromosomes in this present study.…”

“…Meiotic abnormalities or irregularities observed at meiosis probably have a direct relation with pollen fertility (Ranjbar et al 2011). In the present investigation, the pollen fertility of BARI Methi-1, BARI Methi-2, BARI Methi-3, and BARI Firingi-1 was more than 95% though these specimens exhibited several kinds of meiotic abnormalities (Table 5).…”

A new species of Trigonella sect. Ellipticae (Leguminosae-Papilionoideae) from Iran, including cytogenetic and anatomical notes

“…The results of our cytogenetic study showed that the basic chromosome number of x = 8 for the new species is equal to that of all species of T. sect. Ellipticae (Hesamzadeh & Ziaei-Nasab 2009;Ranjbar et al 2011aRanjbar et al , 2012b. Hence, the diploid state has been retained during speciation within this perennial section.…”

Onosma maculata sp. nov. (Boraginaceae) from Iran

“…H, J, D). Desynapsis is considered as the precocious separation of bivalents in metaphase of meiosis I, leading to formation of various numbers of univalents (Ranjbar et al , ). Desynapsis was found only in 2.5% of D/MI cells (Fig.…”