Abstract
1. Data were obtained on the seeds, endosperms, and embryos from cones of previously described trees of Pinus ponderosa. Volumetric measurements were made, cotyledons were counted for embryos from different sizes of seeds, and the rate of growth of the embryos was computed. 2. For a period of about 5 weeks there is little embryonic differentiation, the embryos within each seed being engaged in a competitive struggle for survival-a period of embryonic selection. 3. After the dominant embryo has been established, it spurts ahead in rapid growth and differentiates all its organs in a period of 10-12 days. Seed ripening occurs in a few weeks with little change in embryo size. 4. A great diversity of stages is found among embryos collected on a given date. This makes possible a computation of the presumable rate of growth between successive collections of seeds from the same tree. 5. The average rate of growth is about 1/2 stage per day during embryo differentiation. It is much slower in the smallest seeds. 6. At the time of shoot-tip differentiation and of cotyledon initiation, the volume of the embryo is closely related to the volumes of endosperm and of seed. 7. There exists a correlation among seed size, embryo size, endosperm size, and number of cotyledons in the embryo.
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Claims 9
Claim · model-written summary
Embryos showed little differentiation for about five weeks.
- Taxon
- Pinus ponderosa
Pinus ponderosat0 - Outcome
- embryonic differentiatione0
- Value
- about 5 weekse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For a period of about 5 weeks there is little embryonic differentiation”
t0“Pinus ponderosa”
Claim · model-written summary
Embryos within each seed competed until a dominant embryo survived.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- embryonic selectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the embryos within each seed being engaged in a competitive struggle for survival-a period of embryonic selection”
t0“Pinus ponderosa”
Claim · model-written summary
The dominant embryo grew rapidly and differentiated all organs over 10 to 12 days.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- rapid growth and differentiates all its organse0
- Value
- 10-12 dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After the dominant embryo has been established, it spurts ahead in rapid growth and differentiates all its organs in a period of 10-12 days”
t0“Pinus ponderosa”
Claim · model-written summary
Seed ripening occurred over a few weeks with little change in embryo size.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- little change in embryo sizee0
- Value
- a few weekse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed ripening occurs in a few weeks with little change in embryo size”
t0“Pinus ponderosa”
Claim · model-written summary
Embryos collected on the same date occupied diverse developmental stages.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- diversity of stagese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A great diversity of stages is found among embryos collected on a given date”
t0“Pinus ponderosa”
Claim · model-written summary
Average embryo growth during differentiation was about half a stage daily.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- average rate of growthe0
- Value
- about 1/2 stage per daye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average rate of growth is about 1/2 stage per day during embryo differentiation”
t0“Pinus ponderosa”
Claim · model-written summary
Embryo growth was slower in the smallest seeds.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Material
- smallest seedse0
- Outcome
- average rate of growthe1
- Direction
- slowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is much slower in the smallest seeds”
e1“The average rate of growth is about 1/2 stage per day during embryo differentiation”
t0“Pinus ponderosa”
Claim · model-written summary
At shoot tip differentiation and cotyledon initiation, embryo volume related closely to endosperm and seed volumes.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Organ / stage
- shoot-tip differentiation and of cotyledon initiatione0
- Outcome
- volume of the embryoe0
- Comparator
- volumes of endosperm and of seede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the time of shoot-tip differentiation and of cotyledon initiation, the volume of the embryo is closely related to the volumes of endosperm and of seed”
t0“Pinus ponderosa”
Claim · model-written summary
Seed size, embryo size, endosperm size, and cotyledon number were correlated.
- Taxon
- Pinus ponderosaPinus ponderosat0
- Outcome
- number of cotyledons in the embryoe0
- Comparator
- seed size, embryo size, endosperm sizee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There exists a correlation among seed size, embryo size, endosperm size, and number of cotyledons in the embryo”
t0“Pinus ponderosa”