摘要:

Leaching effects, biological activity of leachates and extracts from unripe endosperms of Triticum. — Unripe endosperms ofTriticum durumcv.Cappelliinhibit germination and depress growth of after-ripe embryos, as revealed by embryo transplantation technique. Leaching of unripe endosperms increases their capacity to depress germination and growth of after-ripe embryos. Bioassay of leachates showed that water soluble substances are removed from the endosperm. These are able to stimulate growth of lettuce hypocothyl. Their removal seems to allow leached endosperms to exibit a depressing activity, unopposed by leached stimulating substances, stronger than unleached endosperms. Fractionation on Sephadex G 10 column of aqueous extract from unripe leached endosperms was carried out to display substances responsible of depressing activity. Bioassay of 12 eluted fractions revealed the presence of two groups of active fractions, which differ for molecular weight (m.w.). These are able to stimulate — fractions with high m.w. — or to depress — fractions with low m.w. — growth of lettuce hypocothyl. The depressing activity of unripe endosperms could be due to low m.w. fractions, of which activity exceeds the stimulating effects of fractions with high m.w. The germination and growth behaviour of unripe caryopses ofTriticummay be explained as a consequence of the relationships between depressing and stimulating growth substances. Their unstable balance controls the behaviour of seed during ripening.

ISSN:0017-0070    

DOI:10.1080/11263507209426534

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

About the presence of two varieties of Ranunculus bullatus L. Karyological and ecological observations in subjects of Sardinia. — In the present paper ecological and cytotaxonomical observations in two varieties of theRanunculus bullatusL.:Ranunculus bullatusL. ssp.eu-bullatusMaire var.plantagineus(Jord. et Fourr.) Maire andRanunculus bullatusL. ssp.eu-bullatusMaire var.supranudus(Jord. et Fourr.) Maire have been carried out. The two entities are indifferent to any rocky substratum and they settle on thin and half-arid muddy-sandy soil. The caryological analysis show the coincidence of the two karyotypes and the attribution of the somatic differences to the natural intraspecific variability. The karyotype formula of each variety is:

ISSN:0017-0070    

DOI:10.1080/11263507209426535

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The unicellular marine algaAcetabularia mediterraneaconstitutes an excellent material for radiobiological research. It was found that gamma radiation (60Co) interferes with the morphogenetic process by producing several types of abnormal morphological differentiation. It is shown that whorl modification, one of the most interesting radioinduced anomalies, takes place both in whole and anucleate cells and that it is a dose dependent phenomenon.

ISSN:0017-0070    

DOI:10.1080/11263507209426536

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Rhododendron ferrugineum L. on dolomitic calcareous soils in the Western Ligurian Alps. — The presence ofRhododendron ferrugineumin some localities of Upper Bormida Valley (Western Liguria) on dolomitic calcareous soils is recorded for the first time. The characteristics of the plant communities in these stations are described and a list of the species found there is given; the main geological, geomorphological and climatic features of the localities are outlined. A particular attention is devoted to the distribution ofRhododendron ferrugineumin Maritimes and Ligurian Alps and to the composition of the plant communities to which it belongs. The author considers that the most important features of the plant communities withRhododendron ferrugineumin Liguria are the following: their occurrence on dolomitic calcareous soils, probably connected with the great amount of humus; their presence at an unusually low altitude and at a short distance from the sea coast, due to numerous ecological factors, particularly to the local conditions of the climate; and their very heterogeneous floristic composition, which can be explained by the shifting downwards of the upper altitudinal belt of vegetation.

ISSN:0017-0070    

DOI:10.1080/11263507209426537

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Young embryos ofEruca sativaMiller, with and without suspensor, were culturedin vitro. The probable importance and/or necessity of suspensor during the embryo development was pointed out. Some data about the suspensor citology are also reported.

ISSN:0017-0070    

DOI:10.1080/11263507209426538

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0017-0070    

DOI:10.1080/11263507209426533

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor