Wang Y.-Q./Публикации

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Автор
АВТОР ПУБЛИКАЦИЙ 2
Wang Y.-Q.
2
Wang Y.-Q.
Автор антэкологических публикаций

, Zhang D.-X.
1
Zhang D.-X.
Автор антэкологических публикаций

, Chen Z.-Y.
1
Chen Z.-Y.
Автор антэкологических публикаций

Annals of Botany
514
Журнал с антэкологическими публикациями.
Oxford University Press · office@annbot.com

. 2004. V. 94. No. 4. P. 583–591. Статья
Background and Aims. Pollen grains of 37 species from 11 genera in the family Zingiberaceae were examined to assess qualitatively starch or lipid contents; the pollen grain and ovule numbers per flower and pollen : ovule ratios were also counted and calculated. Pollen : ovule ratios were studied to reveal patterns of variation in the Zingiberaceae. Methods. Freshly open flowers with dehiscing anthers were collected at random from plants growing in natural habitats or in botanical gardens. Presen
ce of lipids or starch in pollen grains was tested by Sudan solution and IKI solution, respectively, and examined under a microscope. To estimate the pollen and ovule numbers per flower, one anther from each bud was carefully dissected and all pollen grains were counted; ovaries were carefully dissected out of each flower and counted. Whenever possible, at least 10–15 buds were used in the determination.

Key Results. Thirty-three of all the 37 species examined had starchy pollen. Starch was not found in only four species and lipid was not found in only one species; among the four tribes in subfamily Zingiberoideae, all species of Zingibereae and Globbeae had pollen with no starch, Alpineae and Hedychieae had pollen with and without starch, whereas, all species of subfamily Costoideae had starchy pollen with abundant lipids. The mean pollen : ovule ratios in the members of the Zingiberaceae investigated range from 3·25 ± 1·56 to 616·52 ± 117·83.

Conclusions. The pollen nutrition types seemed not related to mating systems. The pollen : ovule ratios in members of the Zingiberaceae with the same breeding system are noticeably lower than those recorded by previous authors. The lower pollen : ovule ratios in this family are presumed to be related to the highly efficient pollination systems, mediated by pollen which can be quite glutinous and the relatively large stigma area. In most of the Alpinia species the anaflexistylous flowers have much larger numbers of pollen grains and higher pollen : ovule ratios than the cataflexistylous flowers. There are significant differences in mean pollen grain numbers and pollen : ovule ratios between different life forms but ovule numbers are approximately the same.
AID0090980130
Оригинал
Wang Y.-Q.
2
Автор антэкологических публикаций

, Melzer R.
2
Автор антэкологических публикаций

, Theißen G.
1
Автор антэкологических публикаций

Annals of Botany
514
Журнал с антэкологическими публикациями.
Oxford University Press · office@annbot.com

. 2011. V. 107. No. 9. P. 1445–1452. Статья
Background and AimsHomeotic transitions are usually dismissed by population geneticists as credible modes of evolution due to their assumed negative impact on fitness. However, several lines of evidence suggest that such changes in organ identity have played an important role during the origin and subsequent evolution of the angiosperm flower. Better understanding of the performance of wild populations of floral homeotic varieties should help to clarify the evolutionary potential of homeotic mut
ants. Wild populations of plants with changes in floral symmetry, or with reproductive organs replacing perianth organs or sepals replacing petals have already been documented. However, although double-flowered varieties are quite popular as ornamental and garden plants, they are rarely found in the wild and, if they are, usually occur only as rare mutant individuals, probably because of their low fitness relative to the wild-type. We therefore investigated a double-flowered variety of lesser periwinkle, Vinca minor flore pleno (fl. pl.), that is reported to have existed in the wild for at least 160 years. To assess the merits of this plant as a new model system for investigations on the evolutionary potential of double-flowered varieties we explored the morphological details and distribution of the mutant phenotype.MethodsThe floral morphology of the double-flowered variety and of a nearby population of wild-type plants was investigated by means of visual inspection and light microscopy of flowers, the latter involving dissected or sectioned floral organs.Key ResultsThe double-flowered variety was found in several patches covering dozens of square metres in a forest within the city limits of Jena (Germany). It appears to produce fewer flowers than the wild-type, and its flowers are purple rather than blue. Most sepals in the first floral whorl resemble those in the wild-type, although occasionally one sepal is broadened and twisted. The structure of second-whorl petals is very similar to that of the wild-type, but their number per flower is more variable. The double-flowered character is due to partial or complete transformation of stamens in the third whorl into petaloid organs. Occasionally, ‘flowers within flowers’ also develop on elongated pedicels in the double-flowered variety.ConclusionsThe flowers of V. minor fl. pl. show meristic as well as homeotic changes, and occasionally other developmental abnormalities such as mis-shaped sepals or loss of floral determinacy. V. minor fl. pl. thus adds to a growing list of natural floral homeotic varieties that have established persistent populations in the wild. Our case study documents that even mutant varieties that have reproductive organs partially transformed into perianth organs can persist in the wild for centuries. This finding makes it at least conceivable that even double-flowered varieties have the potential to establish new evolutionary lineages, and hence may contribute to macroevolutionary transitions and cladogenesis.