Standorts- und ernaehrungskundliche Untersuchungen zur Nutzung landwirtschaftlicher Flaechen fuer die Erzeugung von Biomasse mit schnellwachsenden Baumarten Zusammenfassung der Ergebnisse fuer die Jahre 1988 bis 1993. Abschlussbericht

An interdisciplinary field experiment with 4 fast growing poplar and willow clones was established in 1983 on land previously used agriculturally in order to investigate the influence of site, as well as the nutritional and growth aspects and the ecological consequences of this type of land use. At the end of the second rotation period (winter 1992) the height of the poplar clone Muhle Larsen amounted to 7 m, of the aspen Astria and the willow to about 5 m. Dry matter shoot biomass was 20 t/ha for Astria, 30 t/ha for the willow and 32 t/ha for Muhle Larsen. Production on soils subjected to high groundwater was lower than on moderately moist soils. Unfertilized poplars showed optimum nutrition even 10 years after planting. Nitrogen fertilization significantly enhanced shoot biomass only for Salix viminalis. Results of soil inventories in 1983, 1986 and 1992 showed a slight decrease of soil reaction by time. The organic matter and the total nitrogen concentration and the microbial biomass of the soils increased in layers near the soil surface and decreased in deeper layers of the former plough horizon, respectively. Species number of the ground vegetation increased at the afforested sites as compared with a control field. Some groups of the soil macrofauna (woodlice, earthworms, harvestmen) advanced in abundance and activity or showed an increase in biological diversity (carabid beetles). (orig.)SIGLEAvailable from TIB Hannover: F95B93+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Crescimento de plântulas de Pfaffia glomerata (Spreng.) Pedersen cultivadas in vitro sob dois níveis de nitrogênio e sacarose, durante seis subculturas sucessivas e aclimatização Growth of Pfaffia glomerata (Spreng.) Pedersen in vitro cultured plantlets on two levels of nitrogen and sucrose, during six successive subcultures and acclimatization

O presente trabalho objetivou avaliar o crescimento de ginseng brasileiro (Pfaffia glomerata (Spreng.) Pedersen) cultivado in vitro sob dois níveis de nitrogênio e sacarose, durante seis subculturas sucessivas e aclimatização. Como fonte de explantes, utilizou-se segmentos nodais de plantas previamente estabelecidas in vitro. Foram testados dois tratamentos: 100% da concentração padrão de N do meio MS + 30g L-1 sacarose; e 50% da concentração padrão de N do meio MS + 45g L-1 sacarose. Durante as seis subculturas sucessivas, os explantes de plantas cultivadas por 30 dias em ambos os tratamentos foram transferidos, respectivamente, para a subcultura seguinte nos mesmos tratamentos. Ao final da 6&ordf; subcultura, as plântulas foram transferidas para substrato Plantmax® Hortaliças e submetidas à aclimatização em sala de crescimento. Durante as subculturas, observou-se flutuações nas respostas de crescimento das plântulas às duas condições nutricionais testadas. A altura da maior brotação, a média da altura das brotações e o total de segmentos nodais por plântula, respectivamente em quatro, quatro e três subculturas, foram maiores em 100% da concentração padrão de N do meio MS + 30g L-1 sacarose do que em 50% da concentração padrão de N do meio MS + 45g L-1 sacarose. Por outro lado, as matérias secas de raízes, da parte aérea e do total das plântulas, respectivamente em duas, duas e três subculturas, foram maiores em 100% da concentração padrão de N do meio MS + 30g L-1 sacarose. Concluiu-se que o aumento da concentração de sacarose associado à redução da concentração do N estimula a produção de biomassa, enquanto o meio MS padrão estimula o crescimento em altura e número de segmentos nodais. As diferenças quanto à produção de biomassa observadas no cultivo in vitro não se refletiram no processo de aclimatização ex vitro, onde o meio MS padrão proporcionou maior crescimento em altura e número de folhas por planta.<br>The present research was aimed at evaluating the growth of brazilian ginseng (Pfaffia glomerata (Spreng.) Pedersen) in vitro cultured plantlets under two levels of nitrogen and sucrose, during six successive subcultures and acclimatization. Two nutritional treatments were tested: nitrogen at 100% strength of the MS medium + 30g L-1 sucrose; and nitrogen at 50% strength + 45g L-1 sucrose. During six successive subcultures, the explants of 30-day-old plantlets grown under both treatments were transferred, respectively to the next subculture on the same treatment conditions. At 6th subculture, plantlets were transferred to substrate Plantmax® Hortaliças and submitted to acclimatization in a growth chamber. Throughout the subcultures, fluctuations in growth response due to nutritional conditions tested were observed. The height of the higher sprout, the average height of sprouts, and the total number of nodal segments per plantlet, respectively for four, four and three subcultures were greater in 100% strength of the MS medium + 30g L-1 sucrose than in 50% strength + 45g L-1 sucrose. On the other hand, dry matter of roots, of shoots and of the whole plant, respectively for two, two and three subcultures, were greater in 50% strength + 45g L-1 sucrose. In conclusion, the increase of sucrose associated with reduction of N level in the culture medium enhanced the biomass production, while the MS at full strength enhanced the growth based in sprout length and number of nodal segments. These differences concerning the biomass production observed during in vitro culture did not persisted in the acclimatization process ex vitro, where MS at full strength give rise greater growth in sprout length and number of leaves per plant