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.
Parasite surveys of free-ranging wildlife provide important information for monitoring population health. Between March 2001 and March 2003, we sampled 10 ocelots (Leopardus pardalis), eight Geoffroy's cats (Oncifelis geoffroyi), a jaguarundi (Herpailurus yaguarondi), five pampas foxes (Pseudalopex gymnocercus), and three crab-eating foxes (Cerdocyon thous) at three sites in the Bolivian Chaco. The objective of the study was to survey the parasite fauna of these carnivores and compare prevalence of parasites among the sites. The parasite community of these carnivores was diverse, with representatives from eight genera of nematodes, two families of cestodes, two protozoan species, and six arthropod species. Fecal parasites identified from 12 of the 13 felids and five of the six canids examined included Aelurostrongylus abstrusus, Ancylostoma tubaeforme, Uncinaria sp., Crenosoma sp., Toxocara cati, Spirurida, Capillaria aerophila, Spirometra sp., Taeniidae, and Cystoisospora sp. Four tick species, Amblyomma parvum, A. tigrinum, A. ovale, and A. cajennense, and two flea species, Pulex irritans and Delostichus phyllotis, were identified. Two crab-eating foxes had serologic evidence of heartworm disease (HWD). Antibodies against Toxoplasma gondii were found in 15 of 26 animals. Although HWD was found only in canids inside the national park, parasite prevalence did not appear to differ among sites, and no evidence was found of parasite spillover from domestic to wild carnivores. 相似文献
Amaranthus leaf mottle virus (AmLMV) was classified as a member of the genus Potyvirus on the basis of its particle morphology, serology, and biological properties (Casetta et al., 1986). Based on these properties, an Amaranthus viridis-infecting virus isolated in Spain, causing mottle and leaf blistering as well as reduced growth has been identified as AmLMV.
The 3′ terminal genomic region of this and a reference isolate from Italy has been sequenced and reveals a 95% nucleotide
identity between the two isolates. The sequenced part comprises the coat protein with 281 amino acids and 315 nucleotides
of the 3′ untranslated region (UTR) preceding a polyadenylated tail. Pairwise comparisons and phylogenetic analysis of the
nucleotide and deduced amino acid sequences of the CP and 3′ UTR of the cloned cDNAs with those of other potyviruses shows
that AmLMV is a distinct potyvirus closely related to Potato virus Y.相似文献
Shoot growth and dieback were compared among progenies of nursery-grown seedlings of Nothofagus obliqua belonging to seven progenies of the same provenance (Quila-Quina, Argentina). First-year shoots consisted of one growth unit (GU) and second-year shoots of one or two GUs. The probability of development of two GU was similar for all progenies. Progenies were different in terms of shoot size, terminal bud abscission, the extent of shoot dieback after shoot extension and the node of origin of the relay shoot on the first shoot. Plants with a second-year shoot consisting of two GUs had a thicker stem and more nodes than those with single-GU shoots. The selection of N. obliqua seed trees based on architectural traits suitable for forestry development at specific sites must contemplate variability among progenies and their probabilities of successful development under different conditions. 相似文献
Patterns of shoot elongation of 2-yr seedlings from native North American populations of ponderosa pine and Douglas-fir were compared to those of Argentine land races originating from unknown provenances. The comparisons were conducted in Moscow, Idaho (USA), and suggested that the ponderosa pine land race was descended from a California provenance at low or middle elevations but that the growth potential of the land race was only mediocre in comparison to eight native populations. The Douglas-fir land race exhibited a relatively high growth potential in comparison to 19 native provenances and undoubtedly originated from a mild coastal environment. The results provide concrete recommendations for upgrading the growth potential of the Argentine land races by importing germ plasm of specific provenances. 相似文献
This paper points out the usefulness of biopartitioning micellar chromatography (BMC) using capillary columns as a high-throughput primary screening tool providing key information about the oral absorption, skin permeability, and brain-blood distribution coefficients of 15 polyphenols (6 flavones, 2 flavonols, a flavanone, 2 flavan-3-ols, 3 phenolic acids, and a phloroglucinol) in a simple and economical way. For the compounds studied, except vicenin-2, rutin, chlorogenic acid, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid, maximal oral absorption (>90%) can be expected, if there are not solubility problems or metabolic processes. On the other hand, the most retained compounds in BMC, that is, 5-hydroxyflavone, flavone, and flavanone, show the highest brain-blood distribution coefficients and skin permeability coefficients. 相似文献
New Forests - Previous studies have reported that phosphorus transporters are involved in glyphosate uptake by plants, so phosphorus fertilization might act as an attenuator of glyphosate effects... 相似文献
The amount of short-wave solar radiation willingly tolerated by lactating Holstein cows on pasture was determined in an equatorial semi-arid environment. The study was carried out on a dairy farm located in Limoeiro do Norte, CE, northeastern Brazil. The observed behaviours were as follows: grazing, under the sun, under the shade, standing, lying, ruminating, idling and wallowing in the water. The behaviours were recorded using instantaneous scan sampling at regular intervals of 15 min from 0600 to 1800 hours over 5 days. On all sampling days, the meteorological variables, including local short-wave solar radiation (RS-W, W m?2), were recorded. The RS-W data were divided into five levels. The sun exposure was more frequent under low (100 %) and moderately low (97 %) levels, when RS-W remained below 500 W m?2. The grazing was more intense under low (100 %) and moderately low (93 %) levels. Above 500 W m?2, the grazing time significantly decreased (11 %). The cows avoided grazing under high (0 %) and very high (0 %) levels, when RS-W exceeded 700 W m?2. The ruminating behaviour was more frequent under high (33 %) and very high (37 %) levels, in which the highest averages of RS-W were recorded (815 and 958 W m?2, respectively). The standing posture was more frequent under low (100 %) and moderately low (97 %) levels. Therefore, the critical RS-W level that motivates cows to stop grazing and seek shade was in the interval between 500 and 700 W m?2. 相似文献
This study was conducted to determine the age and liveweight at puberty of 120 crossbred beef heifers submitted to four diets to achieve predetermined weight gains (kg/day): 0.5 (G500; n?=?32), 0.75 (G750; n?=?32), 1.0 (G1000; n?=?29), and 1.25 (G1250; n?=?27). Animals were classified depending on their level of crossing between Nelore (N) and Hereford (H): 25%N-75%H, 37.5%N-63.5%H, 43.7%N-56.7%H, 50%N-50%H, and 75%N-25%H. Reproductive evaluation was performed at the beginning and at the end of the experimental period by ultrasonography and hormone analysis. The average age and liveweight at puberty were 388.0?±?1.9 days and 331.4?±?1.3 kg, respectively. Animals from the 25%N-75%H group reached puberty earlier than heifers from other genetic groups supplemented with G1250 diet (P?<?0.05). Heifers with higher degree of Nelore (75%N-25%H) fed with G1000 diet showed estrus 42 days prior to mating, but only 57 % reached puberty at mating (P?<?0.05). Heifers with follicles of higher diameter reached puberty (P?<?0.05) earlier. Higher average daily weight gain showed a positive effect on follicular diameter and IGF-I level at puberty (P?<?0.01). Concentrations of GH were lower in heifers fed G1250 compared to G1000 diet (P?<?0.05). There was a significant interaction between nutritional level and insulin levels at puberty (P?<?0.01). We demonstrated the relationship between IGF-I and average daily gain on the onset of puberty in heifers. In conclusion, heifers submitted to the higher feeding level showed a higher follicular diameter and were younger at puberty. 相似文献