Studies on the expression of somatic crossing over in Glycine max L.

1970 ◽  
Vol 40 (7) ◽  
pp. 316-321 ◽  
Author(s):  
B. K. Vig ◽  
E. F. Paddock
Genetics ◽  
1973 ◽  
Vol 75 (2) ◽  
pp. 265-277
Author(s):  
B K Vig

ABSTRACT Glycine max (soybean) is one angiosperm which lends itself to the study of somatic crossing over. This is made possible because some varieties have gene combinations Y11Y11, Y11y11 and y11y11 in the segregating populations from Y11y11 plants. The gene in question is responsible for chlorophyll synthesis. The Y11Y11 plants have dark green leaves, Y11y11 are light green and y11y11 plants are golden yellow. The heterozygous plants have dark green, yellow and dark green-yellow (double) spots on the leaves of the untreated control material, whereas the two homozygotes are almost always devoid of somatic sectoring. Application of caffeine, or mitomycin C, to the seeds increased the frequency of double, dark green and yellow spots on the Y11y11 background. Possibly, some dark green or yellow spots originate by failure of one of the two components of what might start as a double spot due to somatic crossing over. The application of NaN3 increases the frequency of dark green or yellow spots, almost exclusively. The two spots increase in equal frequency. The y11y11 plants so treated do not have any light green sectors, but dark green, Y11Y11, plants do develop a few light green or very dark green spots. The data indicate that NaN3 is capable of inducing nondisjunction, but does not cause mutations (at this locus), chromosome fragmentations (segmental losses) or somatic crossing over to an appreciable degree. It has previously been shown that caffeine-induced chromosome rejoining in Vicia faba can be inhibited by treating the roots with NaN3. In the present experiments NaN3 did not affect the processes of somatic crossing over as induced by caffeine or mitomycin C. The effect was additive. This system offers advantages for studying chemical mutagens in that somatic crossing over, point mutations, segmental losses through chromosome breakage and nondisjunction can all be studied in a single treatment to the seeds.


1969 ◽  
Vol 11 (1) ◽  
pp. 147-152 ◽  
Author(s):  
B. K. Vig

Chromosome analysis of the root tips of Glycine max (L.) Merrill variety T219 revealed several aberrations. Chromosome stickiness, reductional groupings and multiple spindles (as well as multipolar spindles) were observed. In our previous work, we had observed the expression of homozygous genotypes on the heterozygous background in the form of small spots on the leaves of this variety. This paper tends to correlate the two findings. The appearance of some of the spots on the leaves is attributed to the loss of one or more chromosomes, besides somatic crossing-over.


Author(s):  
R. W. Yaklich ◽  
E. L. Vigil ◽  
W. P. Wergin

The legume seed coat is the site of sucrose unloading and the metabolism of imported ureides and synthesis of amino acids for the developing embryo. The cell types directly responsible for these functions in the seed coat are not known. We recently described a convex layer of tissue on the inside surface of the soybean (Glycine max L. Merr.) seed coat that was termed “antipit” because it was in direct opposition to the concave pit on the abaxial surface of the cotyledon. Cone cells of the antipit contained numerous hypertrophied Golgi apparatus and laminated rough endoplasmic reticulum common to actively secreting cells. The initial report by Dzikowski (1936) described the morphology of the pit and antipit in G. max and found these structures in only 68 of the 169 seed accessions examined.


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