High levels of pollen dispersal detected through paternity analysis from a continuous Symphonia globulifera population in the Brazilian Amazon     

Francimary da Silva Carneiro  Bernd Degen  Milton Kanashiro  Andre Eduardo Biscaia de Lacerda  Alexandre Magno Sebbenn   《Forest Ecology and Management》2009,258(7):1260-1266

In this study, six highly polymorphic microsatellite loci and a categorical paternity analysis approach were used to investigate the contemporary pollen gene flow in the neotropical tree species Symphonia globulifera. Data for this study were taken from a 500 ha experimental plot in a dense terra firme forest in the Eastern Brazilian Amazon and included the mapping and genotyping of 161 reproductive trees, representing more than 90% of all adult trees, and the collection of 748 open-pollinated seeds from 56 seed-trees over two field seasons (2002 and 2003). High levels of pollen immigration from outside of the study plot were detected in both sampled seed-years (≥49%) suggesting long distance pollen gene flow. Low levels of self-fertilization were also detected (≤2%). The analysis showed long distance pollen dispersal occurred within the study area in both 2002 (δ = 907 ± 652 m SD) and 2003 (δ = 963 ± 542 m SD). Patterns of pollen dispersal distance within the plot were also found to be shorter than the distances between potential male parents and seed-trees. This result indicates that the distance between trees does not explain the identified pollen dispersal pattern. Our results support the hypothesis that animal pollinated species occurring in low-density populations can disperse pollen in long distances, despite the very dense nature of the forest.  相似文献   

Fine root production and turnover in Brazilian Eucalyptus plantations under contrasting nitrogen fertilization regimes   总被引：1，自引：0，他引：1  

C. Jourdan  E.V. Silva  J.L.M. Gonalves  J. Ranger  R.M. Moreira  J.-P. Laclau 《Forest Ecology and Management》2008,256(3):396-404

Nitrogen fertilization increased largely over the last decade in tropical eucalypt plantations but the behaviour of belowground tree components has received little attention. Sequential soil coring and ingrowth core methods were used in a randomized block experiment, from 18 to 32 months after planting Eucalyptus grandis, in Brazil, in order to estimate annual fine root production and turnover under contrasting N fertilization regimes (120 kg N ha⁻¹ vs. 0 kg N ha⁻¹). The response of growth in tree height and basal area to N fertilizer application decreased with stand age and was no longer significant at 36 months of age. The ingrowth core method provided only qualitative information about the seasonal course of fine root production and turnover. Mean fine root biomasses (diameter <2 mm) in the 0–30 cm layer measured by monthly coring amounted to 0.91 and 0.84 t ha⁻¹ in the 0 N and the 120 N treatments, respectively. Fine root production was significantly higher in the 0 N treatment (1.66 t ha⁻¹ year⁻¹) than in the 120 N treatment (1.12 t ha⁻¹ year⁻¹), probably as a result of the greater tree growth in the control treatment throughout the sampling period. Fine root turnover was 1.8 and 1.3 year⁻¹ in the 0 N and the 120 N treatments, respectively. However, large fine root biomass (diameter <1 mm) was found down to a depth of 3 m one year after planting: 1.67 and 1.61 t ha⁻¹ in the 0 N and the 120 N treatments, respectively. Fine root turnover might not be insubstantial in deep soil layers where large changes in soil water content were observed.  相似文献   

Physiological and biochemical responses to low non-freezing temperature of two Eucalyptus globulus clones differing in drought resistance     

Alla Shvaleva  Filipe Costa e Silva  Paula Scotti  Mouhssin Oufir  Jean-François Hausman  Guignard Cedric  Paula Ramos  M. Helena Almeida  M. Lucília Rodrigues  João S. Pereira  M. Manuela Chaves 《Annals of Forest Science》2008,65(2):204-204

We have compared the metabolic responses of leaves and roots of two Eucalyptus globulus L. clones CN5 and ST51 that differ in their sensitivity to water deficits (ST51 is more drought sensitive), with regard to the effect of chilling (10/5 °C, day/night). We studied changes in growth, osmotic potential and osmotically active compounds, soluble proteins, leaf pigments, and membrane lipid composition. Our data showed that both clones have the ability to acclimatize to chilling temperatures. As a result of 10 days of acclimation, an increase of soluble sugars in leaves of treated plants of both clones was observed that disappeared later on. Differences between clones were observed in the photosynthetic pigments and soluble protein content which were more stable in CN5 under chilling. It also was apparent that CN5 presented a less negative predawn water potential (ψ_pd) and a higher leaf turgor than ST51 throughout the chilling treatment. In the case of the CN5, increased total lipids (TEA) and concomitant increase of linolenic acid (C18:3) in leaves after acclimatization may be related to a better clone performance under chilling temperatures. Moreover, a higher constitutive investment in roots in the case of CN5 as compared to ST51 may benefit new root regeneration under low temperatures favoring growth after cold Mediterranean winter.  相似文献   

The yield pattern considering the distance to flow accumulation lines     

J.R. Marques da Silva  L.L. Silva 《European Journal of Agronomy》2008,28(4):551-558

Precision agriculture techniques imply a spatial management of fields and to do so a good understanding of the spatial and temporal variability of yield is needed. Average yield data from seven irrigated maize fields were used to study the yield pattern considering the distance of plants to flow accumulation lines. It was found that there is a significant correlation between average yield and distance to flow accumulation lines (DFL). This correlation is best represented by a polynomial function. The most common shape of the yield pattern curve considering the distance to flow accumulation lines shows that there is an increase in average yield with DFL from 0 to 12.5–17.5 m. Near the flow lines the average yield presents lower values due to drainage problems causing plant growth problems. It was also observed higher yield variability near the flow lines. For higher distances from the flow lines there is a continuous decrease in average yield due to less water availability and other variations of soil properties.  相似文献   

Evapotranspiration of “Superior” grapevines under intermittent irrigation     

Pedro Vieira de Azevedo  Jose Monteiro Soares  Bernardo Barbosa da Silva 《Agricultural Water Management》2008,95(3):301-308

This study deals with the effects of intermittent irrigation on actual evapotranspiration (ET) and leaf area index (LAI) of “Superior” grapevines grown in a semiarid environment in northeastern Brazil. The field experiments were carried out during two consecutive fruiting cycles (dry season and rainy season) of grapevines (Vitis vinifera, L) irrigated by drip at a rate of 2.3 L h⁻¹. Four irrigation time intervals were used as follow: one turn irrigation-time (I-1), two turn irrigation-time (I-2), three turn irrigation-time (I-3), and four turn irrigation-time (I-4). The growing cycles received different amounts of water by irrigation, which for dry and rainy seasons were 470.5 and 243.5 mm, respectively. The ET increased from 5.7 to 7.5 mm day⁻¹ when the irrigation time interval changed from I-1 to I-4 and resulted in a higher value of LAI. The values of ET during the rainy-season growing cycle were much lower throughout the phenological stages, reaching a maximum of 6.4 mm day⁻¹ for I-4 in the maturation stage. For both growing cycles, an increase in the cumulated vineyard evapotranspiration was observed when changing the irrigation time interval from I-1 to I-4, except I-2, which was slightly greater than I-3. Soil water drainage had a very gradual exponential decrease from I-1 to I-4 in both fruiting cycles. The grapevine coefficient under intermittent irrigation can be described as function of days after pruning by polynomial models.  相似文献   

Astaxanthin Delivery Systems for Skin Application: A Review     

Sarah Giovanna Montenegro Lima  Marjorie Caroline Liberato Cavalcanti Freire  Vernica da Silva Oliveira  Carlo Solisio  Attilio Converti  dley Antonini Neves de Lima 《Marine drugs》2021,19(9)

Astaxanthin (AST) is a biomolecule known for its powerful antioxidant effect, which is considered of great importance in biochemical research and has great potential for application in cosmetics, as well as food products that are beneficial to human health and medicines. Unfortunately, its poor solubility in water, chemical instability, and low oral bioavailability make its applications in the cosmetic and pharmaceutical field a major challenge for the development of new products. To favor the search for alternatives to enhance and make possible the use of AST in formulations, this article aimed to review the scientific data on its application in delivery systems. The search was made in databases without time restriction, using keywords such as astaxanthin, delivery systems, skin, cosmetic, topical, and dermal. All delivery systems found, such as liposomes, particulate systems, inclusion complexes, emulsions, and films, presented peculiar advantages able to enhance AST properties, among which are stability, antioxidant potential, biological activities, and drug release. This survey showed that further studies are needed for the industrial development of new AST-containing cosmetics and topical formulations.  相似文献   

Genetic diversity associated with in vitro and conventional bud propagation of Saccharum varieties using RAPD analysis     

C. M. da Silva  C. A. Mangolin    A. S. Mott    M. F. P. S. Machado 《Plant Breeding》2008,127(2):160-165

Polymorphisms in the genomic DNA of eight varieties maintained by conventional bud propagation (via rhizomes) and by in vitro shoot tip cultures were detected by RAPD analysis of sugarcane varieties. The study estimated the genetic diversity induced after in vitro multiplication of these varieties. Higher (28.9%) and lower (12%) numbers of polymorphic bands were detected in plants propagated via rhizomes; the genetic similarity estimate varying from 0.63 to 0.80. Plants of SP90‐3723 and SP91‐1049, or RB85‐5113 and SP90‐3723, varieties involving greater genetic distances may be indicated as progenitors in breeding programmes. In vitro multiplication of RB86‐7515, RB85‐5113, RB83‐5054 and SP86‐42 varieties increases genetic variability, while in vitro multiplication of SP91‐1049, SP90‐1638, RB92‐8064 and SP90‐3723 leads to genetic similarity. Results show that the RAPD technique is an effective tool for detecting polymorphism in sugarcane clones and it allows quick collection of the necessary information (more genetically divergent plant varieties) to guide new crossing in sugarcane breeding programmes.  相似文献   

Investigating pig survival in different production phases using genomic models     

Natlia Galoro Leite  Egbert Frank Knol  Andr Luiz Seccatto Garcia  Marcos Soares Lopes  Louisa Zak  Shogo Tsuruta  Fabyano Fonseca e Silva  Daniela Lourenco 《Journal of animal science》2021,99(8)

Pig survival is an economically important trait with relevant social welfare implications, thus standing out as an important selection criterion for the current pig farming system. We aimed to estimate (co)variance components for survival in different production phases in a crossbred pig population as well as to investigate the benefit of including genomic information through single-step genomic best linear unbiased prediction (ssGBLUP) on the prediction accuracy of survival traits compared with results from traditional BLUP. Individual survival records on, at most, 64,894 crossbred piglets were evaluated under two multi-trait threshold models. The first model included farrowing, lactation, and combined postweaning survival, whereas the second model included nursery and finishing survival. Direct and maternal breeding values were estimated using BLUP and ssGBLUP methods. Furthermore, prediction accuracy, bias, and dispersion were accessed using the linear regression validation method. Direct heritability estimates for survival in all studied phases were low (from 0.02 to 0.08). Survival in preweaning phases (farrowing and lactation) was controlled by the dam and piglet additive genetic effects, although the maternal side was more important. Postweaning phases (nursery, finishing, and the combination of both) showed the same or higher direct heritabilities compared with preweaning phases. The genetic correlations between survival traits within preweaning and postweaning phases were favorable and strong, but correlations between preweaning and postweaning phases were moderate. The prediction accuracy of survival traits was low, although it increased by including genomic information through ssGBLUP compared with the prediction accuracy from BLUP. Direct and maternal breeding values were similarly accurate with BLUP, but direct breeding values benefited more from genomic information. Overall, a slight increase in bias was observed when genomic information was included, whereas dispersion of breeding values was greatly reduced. Combined postweaning survival presented higher direct heritability than in the preweaning phases and the highest prediction accuracy among all evaluated production phases, therefore standing out as a candidate trait for improving survival. Survival is a complex trait with low heritability; however, important genetic gains can still be obtained, especially under a genomic prediction framework.  相似文献   

Synthesis of proximal sensing,terrain analysis,and parent material information for available micronutrient prediction in tropical soils     

Pelegrino  M. H. P.  Weindorf  D. C.  Silva  S. H. G.  de Menezes  M. D.  Poggere  G. C.  Guilherme  L. R. G.  Curi  N. 《Precision Agriculture》2019,20(4):746-766

Precision Agriculture - In developing countries, the use of proximal and remotely sensed data is of critical importance as a less expensive means of obtaining soils information. While proximal...  相似文献   

Use of real-time extend GNSS for planting and inverting peanuts     

dos Santos  Adão Felipe  da Silva  Rouverson Pereira  Zerbato  Cristiano  de Menezes  Patricia Candida  Kazama  Elizabeth Haruna  Paixão  Carla Segato Strini  Voltarelli  Murilo Aparecido 《Precision Agriculture》2019,20(4):840-856

Among the main techniques employed in precision agriculture, yield mapping and automatic guidance of agricultural machines are the best-known to farmers. The objective of this study was to evaluate, using statistical process control tools, the quality of automatic guidance using satellite signals, to reduce positioning errors and losses in peanut digging. The treatments consisted of the use of manual (operator guidance) and automatic (autopilot) guidance with RTX satellite signals in sowing and digging operations. The quality of the operation was evaluated after collection of 30 points spaced at 100 m for each quality indicator, which are the losses and the errors of alignment of the mechanised sets in sowing and digging operations. From the perspective of statistical control, manual guidance was shown to be compromised for the quality indicators of digging losses. Despite the instability in the sowing and digging operations, the use of automatic guidance proved to be accurate. The use of automatic guidance increases the precision and reduces overlaps (<?38 mm, as stipulated by the supplier) for sowing and digging. The manual sowing mean error between overlaps was stable; however, it did not remain constant over time.

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