The morphology and anatomy of the stigma of Petunia hybrida

Konar, R. N.; Linskens, H. F.

doi:10.1007/bf00396321

Cited by 105 publications

(35 citation statements)

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“…The ultrastructure showed elongated cells and intercellular spaces containing electron-dense exudates (arrows in Fig. 6) similar to those observed previously in certain other plants (16). Chloroplasts and other organelles similar to those previously observed in stigma cells were also found in the present case.…”

Section: Effect Of Enzyme Concentration and Time On Hydrolysis Ofsupporting

confidence: 91%

“…The surface of at least the so-called dry stigmas is covered by a cuticle (3,6,(8)(9)(10)(11)(16)(17)(18). Since pollen tube must penetrate this barrier in order to gain entry into the stigma on its way to the ovary, it was suspected that the germinating pollen might use an enzyme which catalyzes the hydrolysis of cutin, the structural component of the cuticle.…”

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confidence: 99%

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Production of a Novel Extracellular Cutinase by the Pollen and the Chemical Composition and Ultrastructure of the Stigma Cuticle of Nasturtium (Tropaeolum majus)

1977

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Germinating nasturtium polen (Tropaeolum majus) is shown to excrete an enzyme(s) which hydrolyzes all types of monomers from biosyntheticafly labeled cutin andp-nitrophenyl esters, which are model substrates for fungal cutases. The poUen cutinase showed an optimum pH near 6.5 and was inhibited by thiol-directed reagents such as phydroxymercurnbenzoate and N-ethyl maleimide but not by diisopropylfluoropbosphate, an "active serine"-directed reagent indicating that the polen enzyme is an "-SH cutinase" unlike the fungal enzyme which is a serine cutinase. Excretion of the pollen cutinse into the extracelular fluid was complete within 4 to 6 bourn at 30 C. Since actinomycin D and cyclohexinide showed little effect on the level of cutinase excreted, it appears that cutinase is an enzyme synthesized prior to germination. Release of cutinase into the medium did not require germination. Electron microscopy revealed the presence of a continuous cutin layer on mature stigma with extensive folds, which are proposed to play a role similar to that played by the celular papifine found in the stigma of other plants. Chemical analysis of stigma cutin by depolymerization and combined gas-liquid chromatogrphy and mass spectrometry showed that this cutin consists of mainly the C,6 family of acids. The major (70%) components were dihydroxy C,6 acids which consisted of 10,16-(64%), 9,16-(16%), 8,16-(12%), and 7,16-(8%) dihydroxy palmitic acid. Deuterium-labeling studies sbowed the presence of 16-oxo-9-hydroxy C,6 acid and 16-oxo-10-hydroxy C,6 add in this cutin. The biochemical and ultratctrl studies indicate that the poUen tube may gain entry into stigma using cutinase excreted by the pollen.tal evidence for the presence of cutinase in germinating pollen consisted of the demonstration that addition of cutin preparation to germinating pollen caused a slight increase in titratable acidity (7,18). With this increase as a measure of cutinase, it was found that the presence of cutinase in germinating pollen was a characteristic of plants which have ' cutinized" stigma. Since fungal extracts also catalyzed release of titratable acids in the presence of cutin, including a cutin preparation from stigma surface, it was suggested that cutinase of germinating pollen was "identical with" cutinase detected in molds (7). Cutinase from neither molds nor pollen had been isolated or characterized and, therefore, it was not possible to compare the enzymes from the two sources. Recently, fungal cutinases, isolated in homogeneous form, have been characterized (22, 23. 25). The products released from cutin by the germinating pollen were also not characterized and therefore it was difficult to determine whether the pollen enzyme released all types of monomers of cutin or only the peripheral fatty acids.In this paper we demonstrate, with the use of radioactive cutin, that germinating pollen from nasturtium excrete an enzyme(s) which releases all types of monomers from apple cutin. Results which suggest that the appearance of this cutinase activity...

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Section: Effect Of Enzyme Concentration and Time On Hydrolysis Ofsupporting

confidence: 91%

mentioning

confidence: 99%

Production of a Novel Extracellular Cutinase by the Pollen and the Chemical Composition and Ultrastructure of the Stigma Cuticle of Nasturtium (Tropaeolum majus)

1977

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“…My observations in G. quadriradiata, reported here, and in Glycine max (TILTON et al 1983;TILTON et al 1984) and my interpretation of relevant literature (LINSKENS 1960(LINSKENS , 1975KoNAR andLINSKES 1966a, 1966b;KANNO and HINATA 1969;MARTIN 1969MARTIN , 1970aMARTIN , 1970bMARTIN andRuBERTE 1972, 1973;KNox et al 1976;DuMAS 1974DuMAS , 1977HINATA and Nismo 1978;HINATA 1978, 1982;CLARKE and KNoX 1978;KRisTEN et al 1979;LoRD and WEBSTER 1979;SHIV ANNA and SASTRI 1981;FERRARI et a/.1981;HINATA et al 1982;CRESTI et al 1982;CIAMPOLINI et al 1983) lead me to believe that lipids comprise the major fraction of all stigmal exudates even though dry stigmas secrete much less lipid relative to protein and carbohydrate than do wet stigmas. Without doubt, lipid compounds account for the great bulk of the exudate volume secreted by wet stigmas.…”

Section: Discussionsupporting

confidence: 71%

Stigma, Style, and Pollen Recognition inGalinsoga QuabriradiataRuiz & Pav. (Compositae)

Tilton¹

1984

Caryologia

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“…When mature pollen land on a mature stigma, they first come into contact with the exudate that completely covers the grains and the emerging pollen tubes, which grow further through the exudate in the intercellular spaces toward the transmitting tissue. The exudate consists of a complex mixture of mainly lipids, proteins, and saccharides (Konar and Linskens, 1966;Cresti et al, 1986). Wolters-Arts et al (1998) showed that the lipids present in the exudate are sufficient and essential for pollen tube initiation and can functionally replace both the exudate and the stigmatoid tissue.…”

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confidence: 99%

STIG1 Controls Exudate Secretion in the Pistil of Petunia and Tobacco

et al. 2005

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The lipid-rich, sticky exudate covering the stigma of solanaceous species such as tobacco (Nicotiana tabacum) and petunia (Petunia hybrida) contains several proteins, of which only some have been characterized to date. Proteome analysis of the stigmatic exudate in both species revealed the presence of a cysteine-rich, slightly acidic 12-kD protein called stigma-specific protein 1 (STIG1). In both tobacco and petunia, Stig1 is highly expressed at the mRNA level in very young and developing flowers, whereas hardly any Stig1 transcript is detected in mature flowers. This expression pattern coincides with the differentiation of the secretory zone, forming the intercellular spaces into which the exudate is secreted. Using reverse genetics, we show that STIG1 is involved in the secretion and merging of exudate lipids in the intercellular spaces of the secretory zone and that plants lacking STIG1 show an accelerated deposition of exudate onto the stigmatic surface. This phenotype was observed both in a petunia knockout mutant and in tobacco transgenic plants. We therefore propose that STIG1 plays a role in the temporal regulation of the essential exudate secretion onto the stigma.

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The morphology and anatomy of the stigma of Petunia hybrida

Cited by 105 publications

References 9 publications

Production of a Novel Extracellular Cutinase by the Pollen and the Chemical Composition and Ultrastructure of the Stigma Cuticle of Nasturtium (Tropaeolum majus)

Production of a Novel Extracellular Cutinase by the Pollen and the Chemical Composition and Ultrastructure of the Stigma Cuticle of Nasturtium (Tropaeolum majus)

Stigma, Style, and Pollen Recognition inGalinsoga QuabriradiataRuiz & Pav. (Compositae)

STIG1 Controls Exudate Secretion in the Pistil of Petunia and Tobacco

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