Ploidy levels

The next examples concern species of Ambrosia L. that are characterized, in the first, by a north-south variation, and in the second, an east-west one, with the added feature of different ploidy levels. The work is that of Seaman and Mabry (1979a, b). In the first example, we will look at A. ambrosioides (Cav.) Payne sampled from southern... 

Gong J, Traganos F, Darzynkiewicz Z. 1993. Simultaneous analysis of cell cycle kinetics at two different DNA ploidy levels based on DNA content and cyclin B measurements. 

Van der Linden, A.G. (1969) Chromosome number and ploidy level in a dutch population of Crenobia alpina Dana (Planaria). Genetica 40, 61-64. 

Three morphotypes have been observed in P. ant-arctica colonial cells and two types of flagellates. Two ploidy levels have been recorded. 

The existence of different morphotypes, two ploidy levels related to phase changes, and the ability of both haploid and diploid stages to divide mitotically (Kornmann 1955 Rousseau et al. 1994 Vaulot et al. 1994), support the existence of a haploid-diploid life cycle in P. globosa. In such life cycles, both haploid and diploid stages are related by sexual processes, meiosis and syngamy, and both are capable of mitotic division (Fig. 3 ... 

Houdan A, Billard C, Marie D, Not F, Saez AG, Young JR, Probert J (2004) Holococcolithophore-heterococco-lithophore (Haptophyta) life cycles flow cytometric analysis of relative ploidy levels. Systemat Biodiv 4 453-465... 

Htisgen U, Buttner P, Muller U, Tudzynski P. Variation in karyotype and ploidy level among field isolates of Claviceps purpurea. J Phytopathol 147 591-597, 1999. 

Brossard, D. The influence of kinetin on formation and ploidy levels of buds arising from N. tabacum pith tissue grown in vitw, Z. Pflanzenphysiol. 78 (1976) 323-333. Brown, D.C.W. and T.A. Thorpe Adenosine phosphate and nicotinamide adenine dinucleotide pool sizes during shoot initiation in tobacco callus Plant Physiol. 65 (1980) 587-590. 

Schoen, D.J. J.J. Burdon A.H.D. Brown.. Resistance of Glycine tomentella to soybean leaft rust Phakopsora pachyrhizi in relation to ploidy level and geographical distribution. Theor. Appl. Genet. 1992, 83, 827-832. 

Triticale is a hybrid of wheat (Triticum) and rye (Secale) that was first bred in labs during the late nineteenth century. When wheat and rye are crossed, wheat is used as the female parent and rye as the male parent (pollen donor). The resulting hybrid is sterile and has to be treated with the alkaloid chemical colchicine to make it fertile so that it can reproduce. Different ploidy levels have been created (i.e., different numbers of chromosomes), but hexaploid triticale has been the most successful. 

Austin et al (l) and Hieke (6) failed to detect significant differences in the rates of light dependent O2 evolution by isolated chloroplasts, between different ploidy levels. We, therefore, conducted an experiment to test whether or not there are differences in the photochemical activity of isolated chloroplasts among various species of wheat at different ploidy levels. We further attempted to correlate the photochemical activity with rates of flag leaf photosynthesis. 

Ploidy levels of the resulting progenies were mixed, as in any chemical induction, because embryonic development is not uniform between oocytes and thus different ploidy levels were achieved. Pair matings also showed different results in terms of representation of ploidy classes, indicating parental influences. A difference in size between ploidy levels, as observed in oyster by McCombie et al (2005a), was used to concentrate tetraploid offspring into pseudocohorts as they developed. 

The increase in the ploidy level often causes anatomical and structural changes, such as changes in the leaves, cell size, number of chloroplasts in cells, etc. [122, 123]. These effects of polyploidy may influence photosynthesis [124], the enzyme activities, the photosynthetic electron transport, and isoenzyme activity [13]. All these manifestations of polyploidy often lead to gigantism, i.e., to increased accumulation of plant biomass [116] and a change in secondary metabolism [13]. 

Two approaches are currently known for obtaining transformed root cultures of different ploidy level transformation of autopolyploid intact plants and in vitro polyploidization of transformed root cultures obtained from diploid intact plants. 

Biosynthetic Potential of Transformed Root Cultures with Different Ploidy Levels... 

D. stramonium L. plants accumulate various alkaloids in different plant organs. However, no differences are detected in the alkaloid profiles of diploid and tetraploid plants. There are differences in the alkaloid spectra of plants of different ploidy levels in the minority alkaloids (less than 1% of the ion current). 

In transformed root cultures, the influence of the ploidy level on the qualitative composition of the biosynthesized alkaloids is clearly defined (Table 7.3). There are certain differences in the alkaloid profiles of intact roots and in the corresponding transformed root cultures of D. stramonium L., which ccmtradicts the widespread assertion about the identity of the secondary metabolism of transformed root cultures and the respective intact roots [132, 134, 137]. Intact roots produce 3-monosubstituted, 2,3-disubstituted, 3,6-disubstituted, 3,6,7-trisubstituted alkaloids, and 3-substituted-6,7-epoxytropanes, while transformed roots biosynthesize mainly 3-monosubstimted and 3,6-disubstituted alkaloids (Table 7.3). 

It should be noted that the two ploidy levels of the transformed root cultures of D. stramonium L. show significant differences as regards the spectrum of the biosynthesized alkaloids. Unlike the diploid, tetraploid-transformed roots biosynthesized ten alkaloids. One of them (entry 15, Table 7.3) was not detected in the diploid root culture of D. stramonium L. The pharmacologically active alkaloid hyoscyamine 1 is the principal alkaloid biosynthesized by both root cultures at 78.8% and 56.6% of the total ion ciuxent in the diploid and tetraploid-transformed roots of D. stramonium L., respectively (entry 9, Table 7.3). In contrast to diploid roots, which accumulate 7.12% apoatropine, the tetraploid-transformed root culture biosynthesize 3-acetoxytropane (28.4%) as a second... 

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