摘要:

By means of thin layer chromatography and gas liquid chromatography the distribution of monoterpenes and flavonoid aglycones in the leaves of 19 samples of 15 species ofAcmadeniahas been investigated. The distribution of flavonol and flavone aglycones shows a close agreement with recently proposed taxonomic divisions within the genus. It is proposed that these patterns may be of importance in interpreting the evolutionary development of the genus.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00970.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A description of the development of marginal leaf nodules inArdisia crispais given. The bacterial endophyte, maintained as a colony in the closed shoot tips of the plant, enters young developing leaves through stomatal pores. With further development the bacterial cells are pushed deeper into the leaf and come into contact with the procambial tissue. The module develops lysischizogenously within the procambium and the microsymbiont occupies the intercellular spaces thus formed. Some of the procambial cells secrete large quantities of nutrient material in which the bacteria thrive and grow. A major vascular strand and a number of smaller strands develop around the periphery of the nodule, enclosing the bacterial mass in a ring of vascular tissue. This major vascular strand runs the length of the leaf margin, splitting up to surround each nodule in turn along the edge. This intimate association of the nodule with the vascular tissue has not hitherto been fully appreciated.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00971.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Three southern Spanish populations ofHelleborusfoetidusL. (Ranunculaceae) were sampled for nectar content in the absence of nectarivorous flower visitors. Nectar volume was measured in individual nectaries of flowers at the same stage in the anthesis cycle. Total nectar content per flower was extremely variable between plants within populations and between flowers within plants, but much less so between populations. Average sugar content per flower was roughly similar in the three populations sampled. High variances in nectar abundance occurred also among nectaries within the same flower. Heterogeneity in pollinator rewards thus occurs simultaneously at several spatial scales, namely between nectaries, between flowers and between plants. This implies a strong component of uncertainty to foraging pollinators, which may therefore tend to avoidHelleborusflowers.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Flowers ofPrimula elatiorexhibit all the dimorphic traits typical of distyly. The difference in pollen production between pin and thrum flowers is not thought to be caused by the pollen size dimorphism. The percentage of pin pollen which is probably viable exceeds that of thrum pollen. In the population studied the morph ratio is 1:1, and plants are randomly dispersed with regard to morph type. Bumblebees are the main pollinators, and analysis of the stigmatic pollen load in naturally |xjllinated flowers shows that pin stigmas receive many more pollen grains than thrum stigmas. Intramorph pollination is considerable in pins, while thrums are subject to some differential pollination. Emasculation experiments have shown that intraflower pollination in the thrum morph is negligible. Aging of pin flowers has a reducing effect on their total pollen loads, while in thrums there is no change in total pollen load after the first days of anthesis.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Two glossoptcrid fructifications from the Permian are described.Mudgea, from Australia, consists of a tuft of scales bearing winged orbicular seeds andBreyteniais an urceolate receptacle with biconvex ovules.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The reproductive units of the Glossopteridae are unisexual gonophylls, some with the potential for direct conversion into angiosperm flowers. Compound fructifications in both major taxa may be anthostrobili or the newly defined anthofasciculi. The enclosure of ovules in the angiosperm manner, but with extrorse orientation, places the beginning of angiospermy in the Permian. A few angiosperm gynoecia are extrorse. The presence of the leaf + branch berberoid unit is traced throughout the plant and accounts for the presence of protostelic bundles in the ventral traces and other parts of the flower. This evidence invalidates the carpel theory, but supports the gonophyll theory. The extensive evidence for relationship from reproductive organs is supported by leaf and petal venation patterns forming a continuous series linking the two taxa.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY