Abstract
The Pelargonium flower has five carpels, each with two ovules, yet it is rare for both ovules to develop into twin embryos. The frequency of twin embryos is correlated with the variance in fertilities but not the low mean fertilities of six cultivars tested. An analysis of variance shows no effect of plastids, whereas a highly significant effect among the cultivars reveals their genetic heterogeneity. The behaviour of selfs and hybrids within and between two unlike cultivars confirms the genetic basis of twin formation both by the non-random occurrence of twins, and by the parent offspring correlation in which the lower the parental twin frequency, the fewer the families with twins among their offspring, and the lower the overall mean. In contrast to the many families of selfs and hybrids without twins, a few have a high frequency reaching up to 16.4 per cent. It is suggested that twin formation may follow the weakening of the inhibition of pollen tube growth that normally appears to restrict fertilization to one ovule per carpel. Owing, perhaps, to seasonal conditions, the survival of embryos in twins is sometimes poorer than in singles, in which case the survival of the upper embryo tends to be better than the lower. The mis-shapen appearance of twin seeds suggests that the better adapted single seed has evolved in response to selection for increased seed size.
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Claims 10
Claim · model-written summary
Twin embryos were rare despite two ovules per carpel.
- Taxon
- Pelargonium
.jpg?width=60)
Pelargoniume0 - Outcome
- rare for both ovules to develop into twin embryose0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“The Pelargonium flower has five carpels, each with two ovules, yet it is rare for both ovules to develop into twin embryos”
Claim · model-written summary
Twin embryo frequency correlated with variance in cultivar fertility.
- Taxon
- PelargoniumPelargoniumt0
- Material
- six cultivarse0
- Outcome
- frequency of twin embryose0
- Qualifier
- variance in fertilitiese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The frequency of twin embryos is correlated with the variance in fertilities but not the low mean fertilities of six cultivars tested”
t0“Pelargonium”
Claim · model-written summary
Twin embryo frequency did not correlate with low mean fertility.
- Taxon
- PelargoniumPelargoniumt0
- Material
- six cultivarse0
- Outcome
- frequency of twin embryose0
- Direction
- note0
- Qualifier
- low mean fertilitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The frequency of twin embryos is correlated with the variance in fertilities but not the low mean fertilities of six cultivars tested”
t0“Pelargonium”
Claim · model-written summary
Plastids had no effect in the analysis of variance.
- Taxon
- PelargoniumPelargoniumt0
- Gene
- plastidse0
- Outcome
- no effect of plastidse0
- Direction
- no effecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An analysis of variance shows no effect of plastids”
t0“Pelargonium”
Claim · model-written summary
Cultivars differed significantly, indicating genetic heterogeneity.
- Taxon
- PelargoniumPelargoniumt0
- Material
- cultivarse0
- Outcome
- genetic heterogeneitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a highly significant effect among the cultivars reveals their genetic heterogeneity”
t0“Pelargonium”
Claim · model-written summary
Self and hybrid families supported a genetic basis for twin formation.
- Taxon
- PelargoniumPelargoniumt0
- Outcome
- genetic basis of twin formatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The behaviour of selfs and hybrids within and between two unlike cultivars confirms the genetic basis of twin formation both by the non-random occurrence of twins”
t0“Pelargonium”
Claim · model-written summary
Lower parental twin frequency corresponded to fewer offspring families with twins and a lower overall mean.
- Taxon
- PelargoniumPelargoniumt0
- Outcome
- families with twins among their offspringe0
- Direction
- fewere0
- Comparator
- parental twin frequencye0
Not reportedMaterial
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the lower the parental twin frequency, the fewer the families with twins among their offspring, and the lower the overall mean”
t0“Pelargonium”
Claim · model-written summary
A few self and hybrid families reached 16.4 per cent twin frequency.
- Taxon
- PelargoniumPelargoniumt0
- Outcome
- high frequencye0
- Value
- 16.4 per cente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a few have a high frequency reaching up to 16.4 per cent”
t0“Pelargonium”
Claim · model-written summary
Twin embryo survival was sometimes poorer than single embryo survival.
- Taxon
- PelargoniumPelargoniumt0
- Outcome
- survival of embryos in twinse0
- Direction
- poorere0
- Comparator
- singlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the survival of embryos in twins is sometimes poorer than in singles”
t0“Pelargonium”
Claim · model-written summary
Upper twin embryos tended to survive better than lower twin embryos.
- Taxon
- PelargoniumPelargoniumt0
- Outcome
- survival of the upper embryoe0
- Direction
- bettere0
- Comparator
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the survival of the upper embryo tends to be better than the lower”
t0“Pelargonium”