Title: Floral morphology and anatomy of Pittosporum tobira (Pittosporaceae)
Author(s): Zhou QY, Fu DZ, An XB
Source: NORDIC JOURNAL OF BOTANY 23 (3): 345-352 2004
Document Type: Article
Language: English
Cited References: 16 Times Cited: 0
Abstract: Comparative studies are made on floral morphology and anatomy of female and male flowers of Pittosporum tobira. The two types of flower differ little from each other in structure at the early stage of floral development, but appear dimorphic towards anthesis. The male flower becomes cryptically bisexual, although its pistil is slender compared to that of the female flower. The stigmas of the male flower are receptive and can induce pollen germination. The structure of the style in the male flower is identical to that in the female flower. Ovules are produced on the protruded parietal placenta in the male flower, but their development is arrested at the stage of the 4-nucleate embryo sac. The female flower is clearly unisexual, with obviously aborted and sagittate anthers. Its pistil is rather plump and can produce darkish red seeds immersed in sticky pulp. The male and female flowers are similar in vascular anatomy. A conspicuous difference between the two types of flower lies in the stamens. Variation of sexual organs in the genus Pittosporum is reviewed. We assume that the flowers of Pittosporum are derived from the hermaphrodite- flowered ancestor and the female flower has become unisexual through partial reduction of sexual organs at a faster rate than the male flower.
Addresses: Fu DZ (reprint author), Chinese Acad Sci, Inst Bot, Beijing 100093, Peoples R China
Chinese Acad Sci, Inst Bot, Beijing 100093, Peoples R China
E-mail Addresses: dzfu2@ns.ibcas.ac.cn
Publisher: NORDIC JOURNAL OF BOTANY, THE SECRETARY BOTANICAL MUSEUM GOTHERSGADE 130, DK-1123 COPENHAGEN K, DENMARK
Subject Category: Plant Sciences
IDS Number: 922JA
ISSN: 0107-055X
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Title: Developmental morphology of obturator and micropyle and pathway of pollen tube growth in ovary in Phellodendron amurense (Rutaceae)
Author(s): Zhou QY, Jin XB, Fu DZ
Source: ACTA BOTANICA SINICA 46 (12): 1434-1442 DEC 2004
Document Type: Article
Language: English
Cited References: 26 Times Cited: 0
Abstract: The developmental morphology of the obturator and micropyle and the pathway of the pollen tubes in the ovarian locule in Phellodendron amurense Rupr. have been investigated by scanning electron microscopy and light microscopy. The obturator of the ovule is of funicular origin. As the ovule is fully developed, the obturator becomes considerably large and closely covers the micropyle. When the pistillate flower reaches the receptive phase, the morphology of the obturator is greatly modified, and its cells on the surface are radially expanded and appear to be columnar, semi-papillar or papillar. Following fertilization the obturator reduces in size and degenerates. The pollen tubes need not necessarily traverse the obturator. Whether the pollen tubes pass the obturator or not depends on the sites at which they enter the ovarian locule. This observation does not support the idea that the obturator mainly serves the function of mechanical guidance for the growth of pollen tubes. Our investigations indicate that the structure of the micropyle changes with the different stages of the reproductive process, and becomes asymmetrical during pollination. The development of the obturator and the micropyle correlates with that of the female gametophyte in P. amurense.
Author Keywords: developmental morphology; micropyle; obturator; Phellodendron amurense; pollen tube pathway
KeyWords Plus: ORNITHOGALUM-CAUDATUM LILIACEAE; REPRODUCTIVE PROCESS; STIGMA; OVULE; ULTRASTRUCTURE; ATTRACTION; PISTIL; STYLE
Addresses: Fu DZ (reprint author), Chinese Acad Sci, Inst Bot, Beijing 100093, Peoples R China
Chinese Acad Sci, Inst Bot, Beijing 100093, Peoples R China
E-mail Addresses: qyzhou@ibcas.ac.cn
Publisher: SCIENCE CHINA PRESS, 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA
Subject Category: Biochemistry & Molecular Biology; Plant Sciences
IDS Number: 880OA
ISSN: 1672-6650