| Summary: | 碩士 === 國立中興大學 === 植物學系 === 83 === This thesis have studied the chromosome characteristics of
indigenous and naturalized Convolvulaceae in Taiwan, including
7 genera 21 species 2 subspecies. The chromosome number 2n=30
is the most general one, which occurs in Hewittia, Ipomoea,
Merremia and Operculina. Cuscuta australis (2n=56), Dichondra
micrantha (2n=28), I. pes-tigridis (2n=28), I. plebeia (2n=60),
Jacquemontia tamnifolia (2n=18) and Merremia gemella (2n=58)
are different from the others.The chromosome numbers of C.
australis, I. plebeia, I. wrightii, M. hirta and M. tridentata
subsp. hastata are reported for the first time. The chromosomes
of this family are small in size and symmetrical in shape. The
frequency of polyploids is low, only 8.7﹪. Both I. plebeia and
M. gemella are tetraploids. B chromosomes are less common and
unstable which could be found in I. gracilis, I. nil, I.
obscura, I. plebeia, I. wrightii and M. tridentata subsp.
hastata. Satellites are found in I. alba, I. cairica, I.
gracilis, I. plebeia,I. wrightii and J. tamnifolia. The genus
Cuscuta has its chromosome quite different from the other
genera. But it still belongs to the Convolvulaceae based on the
primary chromosome basic number. Hewittia, Ipomoea, Merremia
and Operculina are similar in cytological data. This fact
probably indicates that these genera have close relationships.
Jacquemontia is more primitive. Though its morphology resembles
the other genera of this family, there are many differences in
the chromosome characteristics. The genus Jacquemontia should
be grouped to the Jacquemontieae separating from the
Convolvuleae. Dichondra is more advanced in the family, and
should be grouped into the Convolvuloideae as the tribe
Dichondraeae.
|
|---|
