Intermittent Growth of Fruits of Phalaenopsis. A Correlation of the Growth Phases of an Orchid Fruit with Internal Development

Duncan, Robert E.; Curtis, John T.

doi:10.2307/2481654

Cited by 35 publications

(15 citation statements)

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“…However, this study showed that the pollen tube could reach the ovule (chalaza) beyond the funiculus without the matured embryo sac, but only when the embryo sac became two-nucleate. One might consider that the intermittent growth of the pollen tube is restricted to Fagales, but an arrested growth of pollen tubes in the pistil is known in unrelated plant groups such as Rosaceae (17) and Orchidaceae (32,33). Attention should be paid to detecting mutants strictly destitute of any of the steps of the pollen-tube growth we reported because no mutants are known yet in which the pollen tube stops growing in the style or ovule.…”

Section: The Study Of the Mechanism Of Pollen-tube Guidance In Angiosmentioning

confidence: 94%

Intermittent pollen-tube growth in pistils of alders (Alnus)

Sogo

Tobe

2005

Proc. Natl. Acad. Sci. U.S.A.

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In alders, where fertilization occurs Ϸ8 weeks after pollination, the pollen tube (male gametophyte) grows intermittently in four steps in close association with the development of the ovary and its ovules. Pollen tubes stop growing in the style, at the ovarian locule, and at the chalaza (ovule), before reaching an embryo sac for fertilization. At the stage when the ovary develops an ovule primordium in each of the two locules, many pollen tubes germinate on the stigma, and a few of them reach the style, where they remain for Ϸ7 weeks. Thereafter, a single tube resumes growing; with a short stop in the upper space of the ovarian locule, it reaches the older of the two ovules when it has developed a two-nucleate embryo sac. Except in the last step, where the tube grows from the chalaza to an embryo sac (female gametophyte), an eight-nucleate mature embryo sac is not necessary for pollen-tube guidance in the pistil. Although the intermittent pollen-tube growth appears to play an important role in the selection of a single pollen tube from many and one ovule from two, its detection provides insight into the study of the mechanism of pollen-tube guidance.Betulaceae ͉ chalazogamy ͉ Fagales ͉ fertilization ͉ ovule I n flowering plants, fertilization occurs when the pollen tube (male gametophyte) reaches the embryo sac (female gametophyte) through the tissue of the pistil (sporophyte), unifying a sperm nucleus with an egg nucleus. This process suggests interaction not only between the pollen tube and the embryo sac, but also between the pollen tube (and embryo sac) and an intervening tissue, i.e., the tissue of the pistil. Recent studies using mutants of Arabidopsis thaliana that lacked normally developed ovules or embryo sacs showed that the pollen tubes lost their way to the target within the pistil (1-3). However, these studies mainly paid attention to interaction between pollen tubes and the embryo sac, and analysis of the correlation between the pollen-tube growth and the developmental stage of the pistils is still scarce.In a majority of cases, the length of time between pollination and fertilization ranges from 24 to 48 h, and in some plants it is even shorter (4-8). In fagalean species, however, the pollen tube spends Ͼ1 month in the pistil before fertilization occurs, because the ovules are not yet mature when the pistil receives pollen grains on the stigma (9-11). We recently reported the pollentube growth pattern in Casuarinaceae (Fagales), where a unique mode of fertilization (i.e., chalazogamy) in place of the ordinary mode (i.e., porogamy) was reported (12, 13) (for details regarding chalazogamy and porogamy, see Fig. 5A, which is published as supporting information on the PNAS web site). In Casuarina equisetifolia (12), fertilization occurs in five discontinuous steps of pollen tube growth from the stigma to the embryo sac. We suggested that the pollen tube exhibited repeated steps of growth in accordance with the development of the ovary and ovule(s). However, C. equisetifolia develops four to eight emb...

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Section: The Study Of the Mechanism Of Pollen-tube Guidance In Angiosmentioning

confidence: 94%

Intermittent pollen-tube growth in pistils of alders (Alnus)

Sogo

Tobe

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…Following pollination, a prolonged period of reproductive development occurs during which time ovules are formed from rudimentary primordia in the ovary. The time elapsed between pollination and final fertilization among orchid species varies greatly from 7 to 130 days (Duncan and Curtis, 1942), reflecting the amount of time required for the formation of ovules and the mature embryo sacs within. The prolonged development of ovules only after pollination is a unique feature of the orchid flower and, as such, presents a unique opportunity to study the developmental processes of megasporogenesis and female gametophyte development.…”

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confidence: 99%

“…In spite of the obvious advantages of the ovule development system in orchids, only a few comprehensive studies of ovule development have been conducted and in only a few orchid genera. Duncan and Curtis (1942) reported that following pollination in Phalaenopsis, the development of the ovary was intermittent and characterized by three well-defined phases of growth in diameter that could be correlated with interna1 structural development. Severa1 additional studies have examined reproductive development in orchids and provide a description of the process in several Development was assessed by determining hair cell growth following pollination in the presence and absence of AVG and in the presence of AVG plus ethylene (ETH) 6 days after treatment in vitro.…”

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confidence: 99%

Ovary and Gametophyte Development Are Coordinately Regulated by Auxin and Ethylene following Pollination.

1993

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The differentiation and development of ovules in orchid flowers are pollination dependent. To define the developmental signals and timing of critical events associated with ovule differentiation, we have examined factors that regulate the initial events in megasporogenesis and female gametophyte development and characterized its progression toward maturity and fertilization. Two days after pollination, ovary wall epidermal cells begin to elongate and form hair cells; this is the earliest visible morphological change, and it occurs at least 3 days prior to pollen germination, indicating that signals associated with pollination itself trigger these early events. The effects of inhibitors of ethylene biosynthesis on early morphological changes indicated that ethylene, in the presence of auxin, is required to initiate ovary development and, indirectly, subsequent ovule differentiation. Surprisingly, pollen germination and growth were also strongly inhibited by inhibitors of ethylene biosynthesis, indicating that male gametophyte development is also regulated by ethylene. Detailed characterization of the development of both the female and male gametophyte in pollinated orchid flowers indicated that pollen tubes entered the ovary and grew along the ovary wall for 10 to 35 days, at which time growth was arrested. Approximately 40 days after pollination, coincident with ovule differentiation as indicated by the presence of a single archesporial cell, the direction of pollen tube growth became redirected toward the ovule, suggesting a chemical signaling between the developing ovule and male gametophyte. Taken together, these results indicate that both auxin and ethylene contribute to the regulation of both ovary and ovule development and to the coordination of development of male and female gametophytes.

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“…6a). Duncan and Curtis (1942) also reported three well defined phases of fruit growth in Phalaenopsis, where the third phase of growth was correlated to the seed development that usually demands more space for the growth of embryos. In the present investigation, a significantly greater fruit diameter (3.05 ± 0.35 mm) found at 158 DAP is due to the embryo development as observed in the histological section (Table 2; Fig.…”

Section: Discussionmentioning

confidence: 93%

“…In addition, a large number of seedlings can be developed from a pod since orchids produce many tiny seeds. However, orchid ovules are not mature at the time of pollination and the period of time elapsed between pollination and subsequent developmental events such as the formation of the macrogametophyte, fertilization, and the development of orchid embryos varies greatly at both the genus and species level (Duncan and Curtis 1942;Lee et al 2006). Thus, the basic information on pollination biology and embryo development after pollination will aid in designing an effective experimental protocol for asymbiotic seed germination of orchids (Lee et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Fruit harvesting time and corresponding morphological changes of seed integuments influence in vitro seed germination of Dendrobium nobile Lindl.

Vasudevan

Staden

2009

Plant Growth Regul

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In vitro asymbiotic seed germination of Dendrobium nobile varied significantly with fruit harvesting time and growth medium used for culturing seeds. Seeds harvested 129 days after pollination (DAP) possessing globular shaped embryos and a discontinuous cuticle layer showed a substantially greater germination on P668 medium. Alternatively, immature seeds harvested 96 and 116 DAP displayed a significantly lower germination response on various growth media. Most of the ovules at 96 DAP are in archesporial and megaspore mother cell stages, whereas the majority of ovules are mature and fertilized at 116 DAP. Mature seeds harvested 158 DAP also germinated at a higher frequency at Stage 5 (emergence of the first leaf) after 8 weeks of culture on different growth media indicating the absence of testa imposed dormancy in this endangered epiphytic orchid.

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Intermittent Growth of Fruits of Phalaenopsis. A Correlation of the Growth Phases of an Orchid Fruit with Internal Development

Cited by 35 publications

References 0 publications

Intermittent pollen-tube growth in pistils of alders (Alnus)

Intermittent pollen-tube growth in pistils of alders (Alnus)

Ovary and Gametophyte Development Are Coordinately Regulated by Auxin and Ethylene following Pollination.

Fruit harvesting time and corresponding morphological changes of seed integuments influence in vitro seed germination of Dendrobium nobile Lindl.

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