Die waldbauliche Bedeutung der Samenprovenienz bei der Eiche

Ohne Zusammenfassung     

Die waldbauliche Bedentung der Samenprovenienz bei der Eiche

Ohne Zusammenfassung     

Jack beans and vetiver grass growth on iron ore tailing sediments from the Doce River dam disaster in Brazil: plant growth regulator effects under different edaphic conditions

Journal of Soils and Sediments - After the greatest environmental disaster in the history of Brazil and the deposition of the iron ore tailings in alluvial regions, the process of revegetation for...     

Biologische Engerlingsbekämpfung

Ohne Zusammenfassung Mit 2 Abbildungen.     

Aboveground biomass,transpiration and water use efficiency in eucalypt plantation fertilized with KCl,NaCl and phonolite rock powder

Potassium has important physiological functions in eucalypt plantations, increasing their productivity when applied to soil via mineral fertilizers. There is interest in identifying alternative sources to KCl owing to its high cost and limited reserves. The aim of the study was to test the effect of replacing KCl with NaCl and phonolite rock powder. Two comparisons were made: (1) application of 283 kg ha^?1 of KCl compared with that of 2125 kg ha^?1 of phonolite rock powder (equivalent to 170 kg ha^?1 of K₂O in both treatments); (2) application of 139 kg ha^?1 of NaCl compared with that of 183 kg ha^?1 of KCl (equivalent to 2.33 kmol Na and K, respectively). Radial growth, soil water content, leaf water potential (Ψ), accumulated transpiration, stem volume and biomass increment, as well as water use efficiency (WUE) were evaluated. In the first comparison, both fertilizations presented equal values for all characteristics evaluated. In the second, the accumulated transpiration in trees fertilized with KCl was 17% higher than that in plants fertilized with NaCl. In contrast, the WUE was 20% higher in the trees fertilized with NaCl than in those fertilized with KCl, reflecting the lower water consumption for the same increment in stem volume and biomass. We conclude that phonolite rock powder and NaCl are possible substitutes for conventional K fertilization performed with KCl.

     

Chromosomes of salmon (Salmo salar) by leukocyte culture

Chromosome preparations from salmon (Salmo salar) were obtained by means of leukocyte culture. The chromosome number varied from 55 to 60 with a clear maximum of 2n = 58. The chromosomes are tentatively grouped as follows: group A, two large submetacentrics; group B, 14 metacentrics; group C, two large telocentrics; group D, 22 medium telocentrics; group E, 18 small telocentrics.     

Seminal plasma composition and its relationship with physical spermatological parameters of Grass carp (Ctenopharyngodon idella) semen: with emphasis on sperm motility

In this research, the mineral and organic composition of the seminal plasma, physical spermatological parameters and their physiological relationships were investigated in grass carp (Ctenopharyngodon idella). The seminal plasma contained 98.14±5.23 mM L^?1 (Na⁺), 380.85±25.95 mM L^?1 (K⁺), 30.25±4.96 mg dL^?1 (Ca²⁺), 19.16±1.70 mEq L^?1 (Mg²⁺), 1.36±0.11 mg dL^?1 glucose, 0.37±0.08 g dL^?1 total protein, 12.02±1.18 mg dL^?1 cholesterol, 14.85±1.50 mg dL^?1 triglyceride and 43.5±9.56 mg dL^?1 urea. The following spermatological parameters were found: sperm volume 14.44±1.16 mL, sperm motility 80.60±1.55%, movement duration 67.68±4.32 s, density 15.43±0.72 × 10⁹ mL^?1, total density 337.43+45.86 × 10⁹ and pH 7.24±0.17. The Na⁺ and Ca²⁺ ions correlated negatively with spermatozoa motility (r=?0.453, P>0.05 and r=?0.192, P>0.05) respectively. The K⁺ ion correlated positively with spermatozoa motility (r=0.545, P>0.05). But a statistically significant correlation was not observed between sperm motility and seminal plasma parameters. The following correlations were observed between mineral and organic components. The Mg²⁺ was positively correlated with glucose and cholesterol (r=0.692, P<0.05 and r=0.680, P<0.05) respectively. A highly significant positive relationship was also found between Mg²⁺ and total protein (r=0.837, P<0.01). On the other hand, a significantly negative relationship was found between Ca²⁺ and triglyceride (r=?0.639, P<0.05). These parameters should be considered when developing procedures for either artificial fertilization or for cryopreservation of grass carp sperm.     

Natural Stable Isotopes for Determination of Gastrointestinal Transit Time in Fish

This study evaluated the application of stable isotopes of carbon as an alternative and more accurate method to determine gastrointestinal transit time (GTT) in fish by comparing it to the inert marker method. The stable isotope method detects alterations of the normal carbon flow in a biological system by analyzing naturally occurring isotopes of carbon, contrary to studies based on conventional techniques that apply external markers to the diet to determine GTT through visual observation of the color change in feces. Therefore, 320 pacu, Piaractus mesopotamicus juveniles were reared in 32 tanks under two different temperatures (25 and 29 C). The pacu juveniles received two different diets, one based on ingredients derived from C₃ photosynthetic cycle plants and the other based on C₄ plant ingredients, both containing titanium oxide (TiO₂) as a marker. After 40 d, the isotopic signature of the diets was changed, and the marker was replaced by chromic oxide (Cr₂O₃). In the isotopic technique, the feces were analyzed to determine the exchange in the isotopic ratio of carbon δ¹³C. Both methods found that GTT was faster (nearly 6 h) in fish at 29 C when using the C₄/C₃ feeding strategy and slower in fish at 25 C using the C₃/C₄ strategy (15 h by inert marker and 18 h by the isotopic method). In conclusion, GTT determination in pacu juveniles using the stable isotope technique exhibits the same accuracy obtained with the inert marker method at temperatures suitable (nearly 29 C) for the metabolism of these animals.     

Factors influencing the survivorship of the burrowing nematode,Radopholus similis (Cobb.) Thorne in two types of soil from banana plantations in Martinique

The burrowing nematode, Radopholus similis (Cobb.) Thorne, causes the most damage to bananas. To minimize nematicide applications, cropping systems that use fallow, crop rotation and clean planting material have been developed in the French West Indies. In order to optimize the benefit of the intercropping period, we studied the survivorship of R. similis in different soil types and conditions. We monitored the survivorship of calibrated populations of R. similis in the laboratory on a Nitisol and on an Andosol, two soils derived from volcanic ashes and pumices. We studied water potentials ranging from 0 to ?700 kPa on undisturbed soil and on soil previously frozen to get rid of living nematodes. Mortality of adult R. similis decreased regularly, and was fairly well described by Teissier's model. In the previously frozen soils, R. similis survived longer in wet soils (half-life of 21–46 days at 0 to ?5 kPa) than in dry soils (half-life of less than 10 days between ?80 and ?250 kPa). In contrast, in undisturbed soils, R. similis survived longer in dry soils: half-lives ranged from 57 days at ?273 kPa to 17 days at water saturation in the Andosol, and 36 days at ?660 kPa to 14 days at water saturation in the Nitisol. These results are consistent with the absence of anhydrobiosis in R. similis, unlike Pratylenchus coffeae. P. coffeae survivorship curves over time do not follow a model derived from exponential decrease like Teissier's model. These results also show that the recommended one year host-free period required to sanitize soils cannot be shortened without risk, even if flooding the soil could improve it.