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Gituru Wahiti Robe rt Wang Qing |feng Wang Yong Guo You |hao Colleg e of Life Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2003,8(1)
0 IntroductionAlismataceaeisacosmopolitanfamilythatconsistsof 11generaandapproximately 95species[1] .Allthespeciesinthisfamilyareaquaticorsemi aquaticwiththemajorityoccurringintheNewWorld .ThegenusCaldesiaisrestrictedtotheOldWorldfromAfricaandMadagascarandS… 相似文献
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Gituru Wahiti Robert 《武汉大学学报:自然科学英文版》2007,12(2):337-342
Outcrossing rate in a natural population of Caldesia grandis was estimated by the dominant random amplified polymorphism DNA (RAPD) marker using 10 open-pollinated progeny arrays of 24 individuals. The multilocus outcrossing rate estimated based on all 25 RAPD loci was 0.872 ±0.033 and the single-locus outcrossing rate was 0.795 ±0.032. Multilocus estimates did not differ significantly from the single-locus estimates. The fixation index, F, in the progeny estimated from RAPD data was -0.142 ±0.000. The estimates of multilocus outcrossing rates (t_m) and single-locus outcrossing rates (t_s) obtained from MLDT clearly indicate that outcrossing is predominant in the open-pollinated C. grandis population. An empirical analysis suggests that 15 should be the minimum number of dominant marker loci necessary to achieve robust estimates of t_m. 相似文献
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Caldesia parnassi folia (Bassi ex Linn.) Parl. in China has declined in number in recent years and is increasingly faced with the risk of extirpation
arising from anthropogenic changes associated with rapid urbanization and expansion of both agriculture and infrastructure.
To aid in provision of the data needed for effective conservation of the species, studies on the habitat, pollination ecology,
and breeding system ofC. parnassi folia were carried out on natural populations occurring in Southeastern China. Flowering in the study populations extended for
more than eighty days beginning in early summer. Floral anthesis occurred in the morning hours and proceeded rapidly, lasting
about 45 min. Flowers lasted ca. 8 h.Caldesia parnassi folia is self-compatible; however autogamy resulted in lower seed set than geitonogamy and xenogamy as well as free pollination.
The data on pollen/ ovule (P∶O) ratio is consistent with a partially selfing and outcrossing mating system. Interpopulational
crosses yielded similar seed set to within-population crosses. Agamospermy did not occur in the study populations. Propagation
is achieved through seeds as well as through turions which commonly occur in the inflorescences. Flies (Insecta; Diptera)
were the most frequent visitors to the flowers ofC. parnassi folia; however bees (Insecta; Hymenoptera) composed a larger proportion of effective pollinators. The Syrphidae speciesSphaerophoria indiana (Bigot) presents evidence of oligolectic foraging behavior. Recommendations are made on the immediate steps necessary for
conservation ofCaldesia species in China.
Foundation item: Supported by the State Key Basic Research and Development Plan of China (973) (G2000046805) and the National Natural Science
Foundation of China (30070055)
Biography: Robert Wahiti, Gituru (1967-), male, Kenya, Ph. D., research direction: plant biosystematics. 相似文献
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Using information from literature as well as records of localities on herbarium specimen labels at the East African Herbarium
Nairobi (EA), materials ofCissus quadrangularis L.,C. cactiformis Gilg. andC. quinquangularis Chiov. were collected and new localities were sought. On the basis of the nature of their stem angles, the specimens ofC. quadrangularis were sorted into two variants, A and B. Variant A has smooth stem angles while variant B has rough stem angles. The authors
have proposed that variant B should be recognized as a new variety withinC. quadrangularis. Variant A is the type variety ofC. quadrangularis. A map showing the distribution of the two variants in Kenya has been prepared. The rough-edged variant was found to be absent
from the low-lying semi-arid regions of northern Kenya. The variants were found occurring in distinct, separate populations
but without separate geographical patterns. The results of t-test show no significant difference (p=0.05) between the means of measurements of dimensions of various organs in the two variants. The stem angles of specimens
of the two variants were studied under scanning electron microscope (SEM). This showed a clear morphological difference between
the two variants. The results of the investigation support the hypothesis that the variation withinC. quadrangularis represents distinct kinds that can be recognized as taxa at infra-specific level.
Foundation item: Supported by the China Ministry of Education Fund for University Staff Development in Key Subject Areas and
Kenyatta University.
Biography: Robert Wahiti. Gituru (1967-), male, Kenya, Ph. D. candidate, research direction: plant biosystematics. 相似文献
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0 IntroductionItshoeet essuibsdi avi spiroin mi tLiyvceo pvsaisdcaul,a rw hpilcahnt t aclkaesssi faie dve riyni mportant positioninthe evolutionary history of thepteridophytes .Isoetes sinensisis also representativeof a li mited number of aquatic plants that displaycrassulacean acid metabolism[1], which renders thespecies especially valuable for research into thisunique metabolic pathway.Ecology attaches i mportance to the study ofpatterns of various scales[2].The spatial distributionpattern … 相似文献
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RAPD Analysis for Genetic Variation within the Endangered Quillwort Isoetes hypsophila (Isoetaceae) 总被引:2,自引:0,他引:2
CHENJin-ming WANGJing-yuan LIUXing GituruWahitiRobert WANGQing-feng 《武汉大学学报:自然科学英文版》2005,10(2):455-459
The genetie variation in the critically endangered species Isoetes hypsophila was investigated using Random Amplified Polymorphism DNA (RAPD) markers. Thirteen primers were screened from sixty primers, and a total of 104 DNA fragments were scored, of which, 52 were polymorphic loci. Low-level genetic diversity within populations with PPB values ranging from 7.69% to 25.96% was found. An Analysis of Molecular Variance (AMOVA) indicated that the most of variance (78.30%) occurred between Yunnan and Sichuan. The variances among populations within regions and within populations were only 3.89% and 17.82%, respectively. 相似文献
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