Abstract
One of the phenomena uncovered in cytological studies of Abies grandis LIndley, the Lowland White Fir, was the existence of pairing of chromosomes in somatic cells of the very young ovules. Huskins (1948) has shown that somatic pairing is not rare in the plant world, but is seldom properly recorded. It was thought necessary to undertake a study of the morphology of the Individual chromosomes of the tree. Counts and measurements were made on the chromosomes in several cells, and the measurements reduced to a percentage of the total chromosome length in the cell. Positions of the spindle-fibre attachments or centromeres were also tentatively located and recorded as percentages. The lengths of the twelve chromosomes in the genome are as follows: Chromosome 1, 14.4% units long; 2, 11.3% units; 3, 10.6% units; 4, 9.6% units; 5, 9.1% units; 6, 8.4% units; 7, 8.1% units; 8, 1.2% units; 9, 6.4% units; 10, 6.1% units; 11, 5.5% units; 12, 3.3% units. Two chromosomes have club-shaped ends without any constriction, while five have single terminal knobs. One has three constrictions, one has two, and four have but a single constriction. One chromosome is dicentric, four are approximately isomeral, five are distinctly heteromeral, and two have terminal centromeres. Somatic cells from young ovules showing apparent pairing of chromatin strands at early anaphase were examined. In one cell studied, the pairing is so distinct and the similarity between chromatin threads so striking that It is thought to be indication of some sort of reduced meiosis. The differences between somatic pairing and true meiosis are discussed and also some theories on the reason for somatic pairing. Some problems in technique of conifer cytology and the methods used in this study are set forth.
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Claims 6
Claim · model-written summary
Somatic pairing of chromatin strands was observed in young ovules.
- Taxon
- Abies grandis
Abies grandise1 - Organ / stage
- young ovulese0
- Outcome
- apparent pairing of chromatin strands at early anaphasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Somatic cells from young ovules showing apparent pairing of chromatin strands at early anaphase were examined.”
e1“Abies grandis LIndley”
Claim · model-written summary
One cell showed distinct pairing and striking similarity between chromatin threads, interpreted as possible reduced meiosis.
- Taxon
- Abies grandisAbies grandise1
- Outcome
- pairing is so distinct and the similarity between chromatin threads so strikinge0
- Qualifier
- indication of some sort of reduced meiosise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In one cell studied, the pairing is so distinct and the similarity between chromatin threads so striking that It is thought to be indication of some sort of reduced meiosis.”
e1“Abies grandis LIndley”
Claim · model-written summary
Two chromosomes had club-shaped ends and five had single terminal knobs.
- Taxon
- Abies grandisAbies grandise1
- Outcome
- club-shaped ends without any constriction, while five have single terminal knobse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two chromosomes have club-shaped ends without any constriction, while five have single terminal knobs.”
e1“Abies grandis LIndley”
Claim · model-written summary
One chromosome had three constrictions, one had two, and four had one.
- Taxon
- Abies grandisAbies grandise1
- Outcome
- three constrictions, one has two, and four have but a single constrictione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“One has three constrictions, one has two, and four have but a single constriction.”
e1“Abies grandis LIndley”
Claim · model-written summary
One chromosome was dicentric, four approximately isomeral, five heteromeral, and two had terminal centromeres.
- Taxon
- Abies grandisAbies grandise1
- Outcome
- dicentric, four are approximately isomeral, five are distinctly heteromeral, and two have terminal centromerese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“One chromosome is dicentric, four are approximately isomeral, five are distinctly heteromeral, and two have terminal centromeres.”
e1“Abies grandis LIndley”
Claim · model-written summary
The twelve chromosomes had distinct relative lengths ranging from 14.4% to 3.3% units.
- Taxon
- Abies grandisAbies grandise1
- Outcome
- lengths of the twelve chromosomese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lengths of the twelve chromosomes in the genome are as follows: Chromosome 1, 14.4% units long; 2, 11.3% units; 3, 10.6% units; 4, 9.6% units; 5, 9.1% units; 6, 8.4% units; 7, 8.1% units; 8, 1.2% units; 9, 6.4% units; 10, 6.1% units; 11, 5.5% units; 12, 3.3% units.”
e1“Abies grandis LIndley”