Some observations on the stigmatic exudate inPetunia hybrida

1965 ◽  
Vol 52 (22) ◽  
pp. 625-625 ◽  
Author(s):  
R. N. Konar ◽  
H. F. Linskens
Keyword(s):  
Stigmatic Exudate

The floral development and anatomy of Carica papaya (Caricaceae)

1999 ◽  
Vol 77 (4) ◽  
pp. 582-598 ◽  
Author(s):  
LP Ronse Decraene ◽  
E F Smets
Keyword(s):  
Calcium Oxalate ◽  
Carica Papaya ◽  
Floral Development ◽  
Floral Anatomy ◽  
Structural Basis ◽  
Unisexual Flowers ◽  
Stigmatic Exudate ◽  
Large Ovary ◽  
Further Development ◽  
Shed Light

Floral development and anatomy of Carica papaya L. have been investigated to shed light on (i) the morphology of the flower, (ii) the structural basis for the pollination mechanism, and (iii) the relationships of the Caricaceae. Carica is mostly dioecious with a strong dimorphism between staminate and pistillate flowers. The development of staminate flowers resembles that of pistillate flowers up to the initiation of the stamens. Further development leads to highly diverging morphologies. In staminate flowers a combination of contorted growth and the development of a common stamen-petal tube produces a long floral tube. The gynoecium grows into a central spearlike pistillode. The pistillate flowers have no traces of stamens and initiate five antesepalous carpel primordia. Common basal growth leads to the development of a large ovary with staglike stigmatic lobes and intruding placentae covered with numerous ascending ovules. Floral anatomy of staminate and pistillate flowers is described. The nature of the colleters is discussed. The morphological basis for reward production in C. papaya is clarified, and conflicting views on pollination are discussed. Nectaries of staminate flowers are located on the central rudimentary pistil and not at the base of the stamens, as previously reported. The anthers contain packages of calcium oxalate crystals. Pistillate flowers produce no nectar but have a stigmatic exudate. We compared the floral development and anatomy of Carica with that of Adenia (Passifloraceae) and Moringa (Moringaceae) in the view of a relationship with other glucosinolate-producing families. Although a derivation of the unisexual flowers from bisexual ancestors is probable, Storey's hypothetical derivation of pistillate flowers is not supported by the floral ontogeny and vasculature.Key words: Adenia, Caricaceae, Moringa anatomy, calcium oxalate packages, dioecy, floral structure, nectaries, ontogeny, pollination, systematic relationships.

scholarly journals Putrescine Increases Effective Pollination Period in Roses

1992 ◽  
Vol 2 (2) ◽  
pp. 211-213 ◽  
Author(s):  
Serge Gudin ◽  
Laurence Aréne
Keyword(s):  
Pollen Germination ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Rosa Hybrida ◽  
In Vitro Pollen Germination ◽  
Stigmatic Exudate ◽  
Germinated Pollen ◽  
Number Of Seeds

Flowers of two cultivars of Rosa hybrida were treated or not with putrescine before being pollinated from 2 to 8 days after anther emasculation. On both cultivars the 10-3 M putrescine treatment extended the effective pollination period, as shown by the best hip formation rates and mean number of seeds per hip. On one cultivar, the 10-5 M putrescine treatment increased fertilization efficiency (more hips obtained). The effect of putrescine was proportionally more important on the cultivar characterized by the highest stigmatic exudate pH. Putrescine also influenced in vitro pollen germination by increasing the length of emitted pollen tubes (10-3 and 10-5 M-putrescine) and the quantity of germinated pollen grains (10-5 M putrescine).

Pollination Sub-Systems Distinguished by Pollen Tube Arrest after Incompatible Interspecific Crosses in Rhododendron (Ericaceae)

1982 ◽  
Vol 53 (1) ◽  
pp. 255-277
Author(s):  
ELIZABETH G. WILLIAMS ◽  
BRUCE R. KNOX ◽  
JOHN L. ROUSE
Keyword(s):  
Pollen Tube ◽  
Tip Growth ◽  
Interspecific Cross ◽  
Embryo Sac ◽  
Epifluorescence Microscopy ◽  
Interspecific Crosses ◽  
Abnormal Behaviour ◽  
Callose Deposition ◽  
Variable Diameter ◽  
Stigmatic Exudate

The cytology of compatible and interspecific incompatible pollinations has been followed in selected species of the genus Rhododendron (Ericaceae). Pollinated pistils were fixed, cleared, stained in decolourized aniline blue, and observed by epifluorescence microscopy. Ten different abnormalities of arrested pollen tube tips have been detected, including burst, tapered, swollen, coiled, spiralling, spiky and variable diameter syndromes. A series of five errors of callose deposition in incompatible tubes has also been defined. Six different regions in the pistil for expression of pollen tube arrest have been found, including the stigmatic exudate, the mucilage of the upper and lower style canal, the ovary loculus, the micropyle. There may also be abnormal behaviour after entry into the embryo sac. Both the site of pollen tube arrest within the pistil, and the error syndrome of tip growth and callose deposition anomalies, are characteristic of each interspecific cross. These results are discussed in relation to the genetic control of reproduction.

A scanning electron microscope study of the pollen tube pathway in pistils of Rhododendron

1992 ◽  
Vol 70 (5) ◽  
pp. 1039-1060 ◽  
Author(s):  
Barbara F. Palser ◽  
John L. Rouse ◽  
Elizabeth G. Williams
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pollen Tube ◽  
Electron Microscope Study ◽  
Pollen Grains ◽  
Scanning Electron Microscope Study ◽  
Stigma Surface ◽  
Stigmatic Exudate ◽  
Days After Anthesis ◽  
Scanning Electron

The pollen tube pathway was observed at regular intervals in pistils of four species of Rhododendron, with emphasis on Rhododendron fortunei. Rhododendron is characterized by a nonpapillate wet stigma, angled stylar canal, placentae with central clefts, and many unitegmic anatropous ovules. Receptive stigmas were hand-pollinated with self pollen 1 – 8 days after anthesis. The pollen, which occurs in permanent tetrads, started germinating during the 1st day. After crossing the stigma surface to one of the grooves leading into the stylar canal, pollen tubes grew straight through the style, and continued into the placental clefts from which they emerged onto the placental surface to grow among the ovules. Tubes reached the ovary in 5 – 10 days depending on the species and took several days after entering the upper ovary to reach the base of the placentae. Single tubes (rarely two or more) diverged from the interovular network and grew under the integument (which is close against the placental surface) to enter the slit-like micropylar opening of an ovule. The morphology of the micropylar slit and the direction of pollen tube entry showed variation among ovules. In R. fortunei ovule entries occurred first on the upper half of the placenta, though not at the top, and in ovules closest to the placental cleft. All portions of the pathway, from stigma surface to micropylar opening, are covered by exudate. Stigmatic exudate increased in amount and became more viscous after pollination, burying the pollen grains and tubes, then gradually dried. Exudate was produced in the style and ovary whether or not pollination occurred. Characteristics of the pollen tube pathway in Rhododendron are discussed relative to those in other angiosperm taxa. Key words: Rhododendron, pollen–pistil interactions, fertilization, transmitting tissues, pistil exudates, ovule entries.

scholarly journals The Composition of Stigmatic Exudate from Lilium longiflorum

1970 ◽  
Vol 46 (1) ◽  
pp. 150-156 ◽  
Author(s):  
C. Labarca ◽  
M. Kroh ◽  
F. Loewus
Keyword(s):  
Lilium Longiflorum ◽  
Stigmatic Exudate
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