1,721,164 research outputs found
Ultrastructure of develqping chloroplasts and chlorophyll content in a hornwort sporophyte as affected by darkness
No full textCHLOROPLAST DEVELOPMENT IN LIGHT‐ AND DARK‐GROWN SPOROPHYTES OF PHAEOCEROS LAEVIS (L.) PROSK. (ANTHOCEROTOPHYTA)
No full textChloroplast development in light and in darkness was investigated in the sporophyte of the anthocerote, Phaeoceros laevis (L.) Prosk. In both light‐and dark‐grown sporophytes, chloroplasts with an elaborate inner membrane system were found in chlorenchyma cells about 3 mm from the sporophyte base. Development in the dark resulted in a net increase of the average number of grana per unit of chloroplast area and of thylakoids per granum, and a parallel diminution in the chlorophyll a/b ratio. Substantial amounts of chlorophyll were synthesized in the dark. Small, paracrystalline arrays of membranes associated with extensive thylakoid stacks were found in immature plastids of dark‐grown sporophytes. These structures disappeared during early stages of subsequent chloroplast differentiation. These results are the first indication that the anthocerotes do not require light for the differentiation of their photosynthetic apparatus. Copyright © 1987, Wiley Blackwell. All rights reserve
Studi sulla dinamica di decomposizione della lettiera di foglie di Pinus laricio Poiret in Sila
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Denitrification potential of beech soils as influenced by the seasonal cycle.
No full textThe potential for nitrification is appreciable throughout the whole seasonal cycle, but nitrate is depleted at different rates during the year. The highest values of nitrate depletion occurred in late spring, early summer and at leaf-fall when readily available carbon substrates are released from root exudates or from litter decomposition. -from Author
Nitrogen mineralization in southern beech forests.
No full textNitrogen mineralization has been studied in the slightly acidic brown earth on limestone of a beech stand and a beech-fir stand, in the forests of Monte Taburno (Campania Apennines). NH4 is the predominant form of the mineral N in the soil of both stands. Yearly NO3- production is 42.4 kg ha-1 in the beech stand and 47.0 kg ha-1 in the beech-fir stand.-from Author
The contribution of bacteria and fungi to soil biological activity in a Pinus pinea wood on Vesuvius mount
No full textTrace metals accumulation in sediment and in different organs of Phragmites communis Trin. along the Calore river
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