摘要:

A British population ofPrimula vulgariswas visited four times between 1971 and 1976 for study of the nature and functioning of distyly. The stainability and production of pollen from pins exceeded those of thrums. About 20% of pin pollen and 48% of thrum pollen was removed from anthers by insect visitors. Pins and thrums were present in a 1:1 ratio in 1971 but pins outnumbered thrums in 1976. Thrums produced more seeds per flower than pins though the number of ovules produced by each was similar. Two methods for collecting stigmas from open flowers and analyzing them for pollen loans produced somewhat different results. For pin stigmas, the pollen load consisted of 2–23% thrum pollen; for thrum stigmas, the pollen load consisted of 0–71% pin pollen with most stigmas having less than 50% pin pollen. In general, intermorph pollen flow is less than would be expected if pollen flow were random. It is probable that most intramorph pollen on stigmas is a result of self‐ or geitonogamous pollination. The extensive literature concerning the natural pollinators of the primrose is reviewed. Although Darwin's hypothesis concerning the functional significance of distyly in promoting intermorph pollination was never quantified, the pollen flow patterns observed inP. vulgarisare unexpectedly deviant and are similar to those patterns observed in several unrelated heterostylous species in other plant fam

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02181.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Erythroxylum cocais a distylous species with a strong self‐incompatibility system linked with the floral dimorphism. The two sets of stamens in the flowers are usually unequal in length, but between individuals of both morphs there is considerable variation in the relative qengths of the two sets of stamens, which is unrelated to the incompatibility system. Pin flowers produce more pollen grains than thrum flowers, but thrum pollen is larger than pin pollen. Within each morph the two sets of stamens produce pollen grains of slightly different diameter.Erythroxylum novogranateweis also distylous. Pin flowers ofE. novogranatensevar.novogranatenseare partially self‐compatible, while thrum flowers ofE. novogranatensevar.truxillenseare self‐incompatible. Reports of tristyly and of four different morphs in species ofErythroxylumare probably misinterpretations, resulting from limited sampling, of the continuous variation in the relative lengths of the two sets of st

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02182.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Ficus vogeliiis a primitive monoecious species, in which staminate and pistillate flowers are distributed throughout the syconium without localization. There is no bimodal structural distinction between seed flowers and gall flowers, and any pistillate flower is capable of seed production. Each syconium follows a development cycle lasting approximately 45 days. The chief pollen vector is the agaonid waspAllotriozoon heterandromorphum, which is an obligate symbiont. Adult females of this species have mesothoracic “pockets” in which pollen is carried. Adult males do not display the anther‐cutting activity reported in other species. The life cycle of the pollinator is described in relation to the developmental cycle of the syc

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02183.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The oil cell development inLaurus nobilisleaves has been studied. At the early developmental stage, when the cell wall consists of the outer cellulose wall only, the oil cells differ from the neighbouring mesophyll cells in their larger size, lower starch content and in their plastid organization. After the deposition of the lamellated suberin layer and the inner cellulose layer, a wall protuberance (cupule) is formed on the periclinal wall facing the epidermis. From its reaction with periodic acid‐hexamine‐silver nitrate, it is suggested that the cupule is cellulosic. The portion of the inner cellulose wall layer bearing the cupule seems to contain patches of suberin. Plasmodesmata occur in special wall protuberances and appear to become occluded with age. The oil produced inside the protoplast is secreted to the outside of the plasmalemma, and accumulates as a drop at the place predetermined by the cupule. Except at the cupule, the oil drop is surrounded by the plasmale

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02184.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Subsidiary cell formation in leaves of the Oncidieae begins with the production of a trapezoid cell on each side of the guard cell mother cell. The trapezoid cells are formed by oblique divisions in the tiles of cells next to the tile of cells containing the guard cell mother cell. The trapezoid cell usually divides unequally to form a subsidiary cell and a derivative cell. The subsidiary cell is smaller and next to the guard cell mother cell. The derivative cell enlarges and is often indistinguishable from the other epidermal cells. Rarely, polar subsidiary cells are also formed. In very rare cases the smaller of the division products of the trapezoid cell divides to form two subsidiary cells next to each guard cell. Subsidiary cells have been found in all tribes of the epidendroid and vandoid groups, all neottoid tribes examined except the Orchideae, and the subfamily Cypripedioideae. The absence of subsidiary cells in primitive genera of the epidendroid tribes and the presence of subsidiary cells in the most advanced genera of the epidendroid and vandoid groups supports the hypothesis that the presence of subsidiary cells is an advanced condition in the Orchidaceae.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02185.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1979.tb02181a.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY