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1

Microsporogenesis in vivo and in vitro. Autofluorescence of pollen wall of Lilium and changes in pollen wall of Gasteria in Lilium anther

100%
Willemse M. T. M.
Acta Societatis Botanicorum Poloniae
|
1981
|
tom 50
|
nr 1-2
2

Interactions with the environment during plant sexual reproduction and dispersal consequences for the concept of sexual reproduction and life

100%
Willemse M. T. M.
Acta Biologica Cracoviensia. Series Botanica
|
2005
|
tom 47
|
nr 1
The interaction between seed plants and animals during pollination and fruit and seed dispersal is well known, and marks the sexual reproduction process. During the history of the plant kingdom, the development of sexual reproduction has been governed by changes in the environment of the plant, together with the increasing complexity of organisms. The interactions between gametes and the environment are prepared during gametogenesis, and therefore reproduction and dispersal are related from the beginning. The dynamic environment should be considered as an interactive partner. The more intensive interactions in multicellular organisms make the interaction in seed plants far more complex. Sexual reproduction plays a key role in the progress of the interaction between the dynamic environment and the biosphere. Sexual reproduction embodies the renewal and dispersal of organisms. This means that the interactions between organisms and their environment are not only an essential element of sexual reproduction but also a characteristic of life, based on the unity of organism and environment. The driving force of the increasing complexity of life is the dynamic environment and the persisting organism.
3

Increased carbohydrate supply in the pollen tube pathway after cross-pollination of Gasteria verrucosa [Mill.] H.Duval

100%
Willemse M. T. M.
Acta Biologica Cracoviensia. Series Botanica
|
2000
|
tom 42
|
nr 2
Gasteria has ovular incompatibility, and recognition of cross- and self-pollen takes place. Cross-pollination includes recognition and pistil activation and leads to seed set. Self-pollen germinate, and their pollen tubes penetrate the ovules but after fertilization they abort. A group of glycoproteins in the pollen coat seems implicated as signal molecules for recognition and activation. Pistil activation is expressed as extra water uptake in the pistil, especially in the fluid pollen tube pathway, and results in higher in vitro pollen tube penetration in the ovular micropyle. In the fluid pollen tube pathway of unpollinated styles a high concentration of sucrose, glucose and fructose is present. The level of these carbohydrates remains the same during the pollen tube growth of cross-pollen. This level decreases after the passage of self-pollen through the stylar channel, and the level of carbohydrates is restored. This implies extra carbohydrate influx in the pollen tube pathway after cross-pollination. Recognition and activation signals act together after cross-pollination of Gasteria. After self-pollination the utilization of carbohydrates lowers the pistil’s carbohydrate capacity, perhaps also leading to a late-acting incompatibility.
4

Recognition and activation signals during pollination in Gasteria verrucosa [Mill] H.Duval

100%
Willemse M. T. M.
Acta Biologica Cracoviensia. Series Botanica. Supplement
|
1999
|
tom 41
|
nr 1
5

Plant sexual reproduction: Aspects of interaction, history and regulation

100%
Willemse M. T. M.
Acta Biologica Cracoviensia. Series Botanica
|
2003
|
tom 45
|
nr 1
Sexual reproduction in angiosperms is an interactive process involving the sporophyte, gametophytes, embryo and endosperm as well as the environment, aimed at achieving pollination, fertilization and dispersal. This interaction occurs via an interface with nutrients and signals outside the cell and even outside the plant. Sexual reproduction has a history. In water, algae have different types of sex organs and gametes, and in some cases the female gamete stays on the plant. The zygote uses water movement and gravity for dispersal. Some algae have alternation of generations in the life cycle, and only the gametophyte functions in sexual reproduction. On land, ferns and mosses inherited alternation of generations, with oogamy and zygote development on the gametophyte, with wind dispersal of the meiospore. In angiosperms, heterospory and the retention of the megaspore, megagametophyte and embryo on the sporophyte lead to a seed with gravity and biotic dispersal. The history of sexual reproduction is based on sex determination, due to cross-fertilization and recombination. Sex differentiation is manifested in the increasing complexity of interaction in the nutrient supply, the retention of the gametophyte or even the embryo, and the type of vector of dispersal. Regulation of sexual reproduction in angiosperms is governed mainly by the sporophyte, with the expression of new genes for biotic pollination and seed dispersal. In the heterotrophic gametophyte some gene expression is suppressed. The development of sexual reproduction is due to the communication between the organism and a dynamic environment.
6

Megasporogenesis and early megagametogenesis

63%
Willemse M. T. M., De Boer-de Jeu M. J.
Acta Societatis Botanicorum Poloniae
|
1981
|
tom 50
|
nr 1-2
7

The function of the tapetal tissue during microsporogenesis in Lilium

63%
Reznickova S. A., Willemse M. T. M.
Acta Societatis Botanicorum Poloniae
|
1981
|
tom 50
|
nr 1-2
8

Apomixis in Brachiaria decumbens Stapf.: gametophytic development and reproductive calendar

63%
Dusi D. M. A., Willemse M. T. M.
Acta Biologica Cracoviensia. Series Botanica
|
1999
|
tom 41
Brachiaria decumbens is a forage grass widely cultivated in tropical areas. This apomictic species reproduces mainly by facultative apospory. A comparison of male and female gamete development between the diploid sexual ecotype and the tetraploid apomictic B. decumbens was made. Aspects of sporophytic and gametophytic development such as developmental stage, several morphological variations, and callose deposition during meiosis are compiled in a real-time reproductive calendar which can be used to select plants as well as reproductive stages. Based on this calendar, part of the differences observed may be related to tetraploidy. Apomictic embryo sacs are formed earlier than the sexual ones, and callose deposition during meiosis follows a different pattern in sexual and apomictic plants. Effects of apomixis are expressed during both male and female development.
9

Analysis of poly[A] plus RNA distribution during maize somatic embryogenesis using digoxigenated oligo-dT probes

51%
Bimal R., Bronsema F. B. F., Willemse M. T. M., Schel J. H. N.
Acta Societatis Botanicorum Poloniae
|
1996
|
tom 65
|
nr 1-2
25-29
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