Symbiotic capability of calopo rhizobia from an agrisoil with different crops in Pernambuco

Biological nitrogen fixation by rhizobium-legume symbiosis represents one of the most important nitrogen sources for plants and depends strongly on the symbiotic efficiency of the rhizobium strain. This study evaluated the symbiotic capacity of rhizobial isolates from calopo (CALOPOGONIUM MUCUNOIDES) taken from an agrisoil under BRACHIARIA DECUMBENS pasture, sabi�� (MIMOSA CAESALPINIIFOLIA) plantations and Atlantic Forest areas of the Dry Forest Zone of Pernambuco. A total of 1,575 isolates were obtained from 398 groups. A single random isolate of each group was authenticated, in randomized blocks with two replications. Each plant was inoculated with 1 mL of a bacterial broth, containing an estimated population of 10(8) rhizobial cells mL-1. Forty-five days after inoculation, the plants were harvested, separated into shoots, roots and nodules, oven-dried to constant mass, and weighed. Next, the symbiotic capability was tested with 1.5 kg of an autoclaved sand:vermiculite (1:1) mixture in polyethylene bags. The treatments consisted of 122 authenticated isolates, selected based on the shoot dry matter, five uninoculated controls (treated with 0, 50, 100, 150, or 200 kg ha-1 N) and a control inoculated with SEMIA 6152 (=BR1602), a strain of BRADYRHIZOBIUM JAPONICUM The test was performed as described above. The shoot dry matter of the plants inoculated with the most effective isolates did not differ from that of plants treated with 150 kg ha-1 N. Shoot dry matter was positively correlated with all other variables. The proportion of effective isolates was highest among isolates from SABI�� forests. There was great variation in nodule dry weight, as well as in N contents and total N.

New York versus Tragedy and Oedipus. The Legacy of Sophocles and the Sophists in Woody Allen's "Crimes and Misdemeanors"

Beyond the explicit reference to the Greek tragedy and Oedipus, the aim of this article is to show the clear relationship, in the author's opinion, between what the protagonists of the film maintain and the theories of the Greek Sophists about God, the law, etc. An accurate analysis both of their texts and the screenplay of Crimes and Misdemeanors reveals different sophistic roots, which, in this case, cannot be attributed to the constant presence of the Jewish legacy in W. Allen's work.

Effects of tillage systems on physical properties of a cohesive yellow argisol in the northern state of Esp��rito Santo, Brazil

Tillage systems are a key element of the technology of crop production, both with a view to crop yield and from the perspective of soil conservation and sustainability of the production system. The aim of this paper was to evaluate the effects of five tillage systems on the physical properties of a cohesive Yellow Argisol. The experiment was installed in the field on January 21, 2011 and lasted 260 days, in an area previously used as pasture with Brachiaria grass without liming or fertilization, but irrigated by a low pressure spray system. The treatments, in five replications and in a randomized block design, consisted of: 1) disk plow (twice) + disk harrow + ridge-furrow tillage (raising a ridge along the planting row), 135 days after transplanting (DP + RID); 2) disk plow (twice) + disk harrow (DP no RID); 3) subsoiler (SB); 4) disk plow (twice) + disk harrow + scarification with three shanks along the plant row (DP + SPR); and 5) disk plow (twice) + disk harrow + scarification with three shanks in the total area (DP + STA). In all tillage systems, furrows were mechanically opened for the papaya plants. After the treatments, the mechanical resistance to penetration was determined, followed by soil moisture, mean weight diameter (MWD), geometric mean diameter (GMD), bulk density (BD), macroporosity (Ma), microporosity (Mi), and number of fruits per plant. There were differences in penetration resistance (PR) between treatments. The subsoiler was more effective to decrease RP to a distance of 0.35 m from the plants, perpendicular to the plant row. The scarifier resulted in a lower PR than DP or SB, even at the depth of 0.40 m, and it was more effective at greater distances perpendicular to the plant. All tillage systems induced a PR between 2.0 and 3.0 MPa at the depth with the highest concentration of papaya tree roots (0-0.25 m), improving the physical conditions to this depth. There was no statistical difference among the treatments for BD, Ma, Mi, MWD, and GMD at a depth of 0.20 m. The disk plow changed the physical properties of the soil most intensely to a depth of 0.20 m. The use of scarification, reduced tillage with a forest subsoiler, or ridge-furrow tillage did not improve the physical properties in the rhizosphere. Reduced tillage with a forest subsoiler resulted in a lower number of fruits per plant than all other treatments, which did not differ from each other.

Arsenic toxicity in Acacia mangium willd. and mimosa Caesalpiniaefolia benth. seedlings

Acacia mangium and Mimosa caesalpiniaefolia are fast-growing woody fabaceous species that might be suitable for phytoremediation of arsenic (As)-contaminated sites. To date, few studies on their tolerance to As toxicity have been published. Therefore, this study assessed As toxicity symptoms in A. mangium and M. caesalpiniaefolia seedlings under As stress in a greenhouse. Seedlings of Acacia mangium and M. caesalpiniaefolia were grown for 120 d in an Oxisol-sand mixture with 0, 50, 100, 200, and 400 mg kg-1 As, in four replications in four randomized blocks. The plants were assessed for visible toxicity symptoms, dry matter production, shoot/root ratio, root anatomy and As uptake. Analyses of variance and regression showed that the growth of A. mangium and M. caesalpiniaefolia was severely hindered by As, with a reduction in dry matter production of more than 80 % at the highest As rate. The root/shoot ratio increased with increasing As rates. At a rate of 400 mg kg-1 As, whitish chlorosis appeared on Mimosa caesalpiniaefolia seedlings. The root anatomy of both species was altered, resulting in cell collapse, death of root buds and accumulation of phenolic compounds. Arsenic concentration was several times greater in roots than in shoots, with more than 150 and 350 mg kg-1 in M. caesalpiniaefolia and A. mangium roots, respectively. These species could be suitable for phytostabilization of As-contaminated sites, but growth-stimulating measures should be used.

Physical properties of a Red-Yellow Latosol and productivity of a signalgrass pasture fertilized with increasing nitrogen doses

The physical properties and fertility of the soil are important factors in the formation and establishment of pasture. Changes in physical properties affect the movement of water, air, nutrients and roots, which, in turn, affect the productivity and longevity of pastures. The objective of this study was to evaluate the physical properties of the soil and the dry matter yield of a pasture with signalgrass cv. Basilisk (Brachiaria decumbens cv. Basilisk), fertilized with increasing nitrogen doses (N), on a dystrophic Red-Yellow Latosol. The experiment was conducted on the Fazenda Rio Manso of the Universidade Federal dos Vales do Jequitinhonha e Mucuri, in Couto de Magalh��es de Minas, State of Minas Gerais, Brazil. To evaluate the annual forage yield, a split plot scheme in a randomized block design with four replications was used, with N doses (0, 50, 100, 150, and 200 kg/ha/year) in the plots and growing seasons (first and second) in the subplots. For soil evaluation, a split plot scheme was used with N doses (0, 25, 50, 75 and 100 kg/ha/cut) in the plots and three sampling times (prior to the experiment, at the end of the first growing season and at the end of the second growing season) in the subplots in a randomized block design with four replications. This analysis was performed separately at two soil depths (0-3 and 10-13 cm). Forage samples were analyzed for the annual dry matter yield (DMY), and soil samples were analyzed for pre-consolidation pressure (σp), initial soil bulk density (Bd), total pore volume (TPV) and void index (Vd). Higher nitrogen doses increased the dry matter yield of signalgrass pasture and the pre-consolidation pressure of the soil. The total pore volume and void index decreased, and the initial soil bulk density increased, though without promoting soil compaction.

Soil nitrogen dynamics after Brachiaria desiccation

Brachiaria species, particularly B. humidicola, can synthesize and release compounds from their roots that inhibit nitrification, which can lead to changes in soil nitrogen (N) dynamics, mainly in N-poor soils. This may be important in crop-livestock integration systems, where brachiarias are grown together with or in rotation with grain crops. The objective of the present study was to determine whether this holds true in N-rich environments and if other Brachiaria species have the same effect. The soil N dynamics were evaluated after the desiccation of the species B. brizantha, B. decumbens, B. humidicola, and B. ruziziensis, which are widely cultivated in Brazil. The plants were grown in pots with a dystroferric Red Latosol in a greenhouse. Sixty days after sowing, the plants were desiccated using glyphosate herbicide. The plants and soil were analyzed on the day of desiccation and 7, 14, 21 and 28 days after desiccation. The rhizosphere soil of the grasses contained higher levels of organic matter, total N and ammonium than the non-rhizosphere soil. The pH was lowest in the rhizosphere of B. humidicola, which may indicate that this species inhibits the nitrification process. However, variations in the soil ammonium and nitrate levels were not sufficient to confirm the suppressive effect of B. humidicola. The same was observed for B. brizantha, B. decumbens and B. ruziziensis, thereby demonstrating that, where N is abundant, none of the brachiarias studied has a significant effect on the nitrification process in soil.

Two Cultures of Arts Education, Finland and Canada? An integrated View

<b>Taidekasvatuksen kaksi kulttuuria, Suomi ja Kanada? Integroitu n��kemys</b> Tutkimuksessa kuvataan kanadalaisen Learning Through The Arts ���pedagogiikan mukainen suomalainen kokeiluhanke, jonka aikana taiteilija���opettaja-parit opettivat yhdess�� eri oppiaineita koululuokille: esim. matematiikkaa tanssien, biologiaa maalaten tai yhdist��en eri taiteenlajeja projektimuotoiseen oppimiseen. Hanketta arvioitaessa nousee esille, ei niink����n yksitt��isten taiteilijoiden ja opettajien toiminta, vaan pikemminkin Kanadan ja Suomen rakenteelliset sek�� kulttuuriset eroavuudet. Tutkimus sivuaa my��s Suomessa k��yt��v���� keskustelua taiteen hy��dyllisyydest�� ja pohtii samalla taito- ja taideaineiden asemaa koulussa. Ty��n teoreettisessa osassa integroidaan opetussuunnitelmateoriaa, kasvatuksen historiaa ja filosofiaa, t��hdent��en taidekasvatuksen merkityst�� osana koko ihmisen kasvatusta. Opetussuunnitelmateorian osalta tarkastellaan romanttista ja klassista opetussuunnitelmaa, jotka eroavat toisistaan menetelmiens��, sis��lt��jens��, tavoitteidensa sek�� arvioinnin osalta. Ns. kovat ja pehme��t aineet tai matemaattis-luonnontieteelliset aineet vastakohtanaan humanismi, voidaan ymm��rt���� sek�� historiallisia ett�� epistemologisia taustojaan vasten. Pepperin maailmanhypoteesien mukaisesti on kasvatuksen ongelmien ratkaisemiseksi hahmotettavissa nelj�� selv��sti toisistaan eroavaa l��hestymistapaa: formismi; organisismi; mekanisismi; sek�� kontekstualismi. Kantin filosofiaan viitaten tutkimus puolustaa k��sityst�� taiteesta rationaalisena ja propositionaalisena kokonaisuutena, joka ei ole vain kommunikaation v��line, vaan yksi todellisuuden kohtaamisen lajeista, tiedon ja etiikan rinnalla. N��in ajateltuna taito- ja taidekasvatuksen tulisi olla luonteeltaan aina my��s kulttuurikasvatusta. Tutkimuksen tulosten perusteella voidaan v��itt����, ett�� moniammatillinen yhteisty�� monipuolistaa koulun opetusta. Mik��li huolehditaan siit��, ett�� taiteilijat saavat riitt��v��sti koulutusta opettamiseen liittyviss�� asioissa, on mahdollista k��ytt���� taiteilijoita opettajien rinnalla kouluty��ss��.

A genetic and biochemical investigation of malondialdehyde production and turnover in Arabidopsis

Malondialdehyde (MDA) is a small reactive molecule which occurs ubiqui��tous among eukaryotes. Interest in this molecule stems from the fact that it can be highly reactive. In green tissues of plants it is apparently formed pre��dominantly by reactive oxygen species (ROS)-mediated non-enzymatic oxi��dation (nLPO) of triunsaturated fatty acids (TFAs). MDA which is formed by nLPO is widely used as a disease marker and is regarded to be a cel-lular toxin. Surprisingly, sites of ROS production like mitochondria and chloroplasts possess membranes which are enriched in nLPO-prone polyun��saturated fatty acids (PUFAs). In this work we showed that chloroplasts are the major site of MDA production in leaves of adult Arabidopsis thaliana plants, whereas analyses in seedlings revealed accumulation in meristematic tissues like the root tip, lateral roots and the apical meristem region. Char-acterizing the MDA pools in more detail, we could show that MDA in plants was predominantly present in a free, non-reactive enolate form. This might explain why it is tolerated in sites where its protonated form could poten��tially damage the genome and proteome. Analyzing the biological fate of MDA in leaves using labeled MDA-isotopes. we were able to show that MDA is metabolized and used to assemble lipids. The major end-point metabolite was identified as 18:3-16:3-monqgalactosyldiacylglycerol (MGDG), which is the most abundant lipid in chloroplasts. We hypothesize that PUFAs in sites of ROS production, like at PS II in chloroplasts, might act as buffers pre��venting damage of proteins, thereby generating molecules such as MDA. The MDA produced in this way appears predominantly in a non-reactive enolate form in the cell until it fulfills a biological function or until it is metabo��lized in order to assemble polyunsaturated MGDGs. Additionally, nLPO has been reported to increase in pathogenesis and we challenged seedlings and adult plants with necrotrophic fungi. Monitoring MDA during the in��fections, we found MDA pools in seedlings were highly inducible although they were tightly controlled in the leaves of adult plants. - Malondialdehyde (MDA) est une petite molecule r��active pr��sente de mani��re ubiquitaire dans les eucaryotes. L'int��r��t de cette mol��cule vient du fait que celle-ci pourrait ��tre tr��s r��active. Dans les tissus verts des plantes, la majorit�� du MDA est apparement form��e par l'oxydation non-enzymatique (nLPO) des acides gras polyinsatur��s (PUFAs) transmis par des esp��ces ac��tives d'oxyg��ne (ROS). Le MDA form�� par nLPO est souvent utilis�� comme marqueur de maladies et il est consid��r�� comme une toxine cellulaire. Etonnament, les sites de production comme les mitochondries et les chloro- plastes sont riches en PUFAs qui sont sensibles �� la nLPO. Dans cette th��se nous montrons que les chloroplastes r��presentent le site de production de MDA dans les feuilles adultes d'Arabidopsis thaliana. Les analyses de MDA dans les plantules ont r��v��l�� que le MDA s'accumule dans les tissus meris- tematiques comme celles de la pointe de la racine, des racines lat��ralles et du merist��me apical. Par la caract��risation du MDA pr��sent nous avons pu montrer que la majorit�� du MDA ��tait pr��sent sous la forme d'un ��nolate non-r��actif. Ceci pourrait expliquer pourquoi le MDA est tol��r�� dans les sites o�� il pourrait casser le genome ou le prot��ome s'il est pr��sent sous sa forme proton��e. Les analyses du devenir du MDA dans les feuilles par des isotopes du MDA ont montr�� que celui-ci est metabolis�� et utilis�� pour assembler des lipides. Le lipide majoritairement m��tabolis�� a ��t�� identifi�� comme ��tant le 18:3-16:3-monogalactosyldiacylglycerole (MGDG); le lipide le plus abondant dans les chloroplastes. Nous supposons que la pr��sence des PUFAs dans les sites de production du ROS, tout comme le PS II dans les chloroplastes, pourrait jouer un r��le de tampon pour prevenir les prot��ines de diff��rentes d��gradations et ainsi g��n��rer des mol��cules telle que le MDA. La majorit�� du MDA produit par cette r��action est pr��sente dans la cellule sous la forme d'��nolate non-r��actif, jusqu'au moment de son utilisation ou lorsqu'il serra metabolis�� pour produire des MGDGs polyinsatur��s. De plus, il a ��t�� d��crit que nLPO pourait augmenter dans la pathogen��se, et nous avons test�� des plantes adultes et des plantules en pr��sence de champignons n��crotrophiques. L'observation du MDA pendant les infections a montr�� que les concentrations en MDA sont fortement induites dans les plantules mais contr��l��es dans les plantes adultes.

Soybean root growth and crop yield in reponse to liming at the beginning of a no-tillage system

Analyzing the soil near crop roots may reveal limitations to growth and yield even in a no-tillage system. The purpose of the present study was to relate the chemical and physical properties of soil under a no-tillage system to soybean root growth and plant yield after five years of use of different types of limestone and forms of application. A clayey Oxisol received application of dolomitic and calcitic limestones and their 1:1 combination in two forms: surface application, maintained on the soil surface; and incorporated, applied on the surface and incorporated mechanically. Soil physical properties (resistance to mechanical penetration, soil bulk density and soil aggregation), soil chemical properties (pH, exchangeable cations, H+Al, and cation exchange capacity) and plant parameters (root growth system, soybean grain yield, and oat dry matter production) were evaluated five years after setting up the experiment. Incorporation of lime neutralized exchangeable Al up to a depth of 20 cm without affecting the soil physical properties. The soybean root system reached depths of 40 cm or more with incorporated limestone, increasing grain yield an average of 31 % in relation to surface application, which limited the effect of lime up to a depth of 5 cm and root growth up to 20 cm. It was concluded that incorporation of limestone at the beginning of a no-tillage system ensures a favorable environment for root growth and soybean yield, while this intervention does not show long-term effects on soil physical properties under no-tillage. This suggests that there is resilience in the physical properties evaluated.

Dynamic, auxin-responsive plasma membrane-to-nucleus movement of Arabidopsis BRX.

In Arabidopsis, interplay between nuclear auxin perception and trans-cellular polar auxin transport determines the transcriptional auxin response. In brevis radix (brx) mutants, this response is impaired, probably indirectly because of disturbed crosstalk between the auxin and brassinosteroid pathways. Here we provide evidence that BRX protein is plasma membrane-associated, but translocates to the nucleus upon auxin treatment to modulate cellular growth, possibly in conjunction with NGATHA class B3 domain-type transcription factors. Application of the polar auxin transport inhibitor naphthalene phthalamic acid (NPA) resulted in increased BRX abundance at the plasma membrane. Thus, nuclear translocation of BRX could depend on cellular auxin concentration or on auxin flux. Supporting this idea, NPA treatment of wild-type roots phenocopied the brx root meristem phenotype. Moreover, BRX is constitutively turned over by the proteasome pathway in the nucleus. However, a stabilized C-terminal BRX fragment significantly rescued the brx root growth phenotype and triggered a hypocotyl gain-of-function phenotype, similar to strong overexpressors of full length BRX. Therefore, although BRX activity is required in the nucleus, excess activity interferes with normal development. Finally, similar to the PIN-FORMED 1 (PIN1) auxin efflux carrier, BRX is polarly localized in vascular cells and subject to endocytic recycling. Expression of BRX under control of the PIN1 promoter fully rescued the brx short root phenotype, suggesting that the two genes act in the same tissues. Collectively, our results suggest that BRX might provide a contextual readout to synchronize cellular growth with the auxin concentration gradient across the root tip.

Macronutrient uptake, accumulation and export by the irrigated 'vit��ria' pineapple plant

The nutritional state of the pineapple plant has a large effect on plant growth, on fruit production, and fruit quality. The aim of this study was to assess the uptake, accumulation, and export of nutrients by the irrigated 'Vit��ria' pineapple plant during and at the end of its development. A randomized block statistical design with four replications was used. The treatments were defined by different times of plant collection: at 270, 330, 390, 450, 510, 570, 690, 750, and 810 days after planting (DAP). The collected plants were separated into the following components: leaves, stem, roots, fruit, and slips for determination of fresh and dry matter weight at 65 ��C. After drying, the plant components were ground for characterization of the composition and content of nutrients taken up and exported by the pineapple plant. The results were subjected to analysis of variance, and non-linear regression models were fitted for the significant differences identified by the F test (p<0.01). The leaves and the stem were the plant components that showed the greatest accumulation of nutrients. For production of 72 t ha-1 of fruit, the macronutrient accumulation in the 'Vit��ria' pineapple exhibited the following decreasing order: K &gt; N &gt; S &gt; Ca &gt; Mg &gt; P, which corresponded to 898, 452, 134, 129, 126, and 107 kg ha-1, respectively, of total accumulation. The export of macronutrients by the pineapple fruit was in the following decreasing order: K &gt; N &gt; S &gt; Ca &gt; P &gt; Mg, which was equivalent to 18, 17, 11, 8, 8, and 5 %, respectively, of the total accumulated by the pineapple. The 'Vit��ria' pineapple plant exported 78 kg ha-1 of N, 8 kg ha-1 of P, 164 kg ha-1 of K, 14 kg ha-1 of S, 10 kg ha-1 of Ca, and 6 kg ha-1 of Mg by the fruit. The nutrient content exported by the fruits represent important components of nutrient extraction from the soil, which need to be restored, while the nutrients contained in the leaves, stems and roots can be incorporated in the soil within a program of recycling of crop residues.

Variability of root traits in common bean genotypes at different levels of phosphorus supply and ontogenetic stages

Selection of common bean (Phaseolus vulgaris L.) cultivars with enhanced root growth would be a strategy for increasing P uptake and grain yield in tropical soils, but the strong plasticity of root traits may compromise their inclusion in breeding programs. The aim of this study was to evaluate the magnitude of the genotypic variability of root traits in common bean plants at two ontogenetic stages and two soil P levels. Twenty-four common bean genotypes, comprising the four growth habits that exist in the species and two wild genotypes, were grown in 4 kg pots at two levels of applied P (20 and 80 mg kg-1) and harvested at the stages of pod setting and early pod filling. Root area and root length were measured by digital image analysis. Significant genotype �� P level and genotype �� harvest interactions in analysis of variance indicate that the genotypic variation of root traits depended on soil nutrient availability and the stage at which evaluation was made. Genotypes differed for taproot mass, basal and lateral root mass, root area and root length at both P levels and growth stages; differences in specific root area and length were small. Genotypes with growth habits II (upright indeterminate) and III (prostrate indeterminate) showed better adaptation to limited P supply than genotypes of groups I (determinate) and IV (indeterminate climbing). Between the two harvests, genotypes of groups II and III increased the mass of basal and lateral roots by 40 and 50 %, respectively, whereas genotypes of groups I and IV by only 7 and 19 %. Values of the genotypic coefficient of determination, which estimates the proportion of phenotypic variance resulting from genetic effects, were higher at early pod filling than at pod setting. Correlations between shoot mass and root mass, which could indicate indirect selection of root systems via aboveground biomass, were higher at early pod filling than at pod setting. The results indicate that selection for root traits in common bean genotypes should preferentially be performed at the early pod-filling stage.

Discours ��conomique et ��volution institutionnelle, les apports de J. R. Commons

John Roger Commons est, de mani��re quasi syst��matique, consid��r�� comme l'un des p��res fondateurs de l'ancien institutionnalisme am��ricain. On souligne tout aussi couramment l'influence que la philosophie pragmatiste a pu avoir sur ses travaux, du moins en ce qui concerne son ouvrage de 1934. Plus rares sont les commentateurs soulignant le r��le qu'a le langage, a fortiori le langage de l'��conomiste, dans l'analyse qu'il fait de l'��volution institutionnelle. Notre but sera de souligner ce fait : pour Commons, dire c'est faire, dans la lign��e de la linguistique performativiste, dire c'est agir sur l'��volution institutionnelle. Abstract : John Roger Commons is well known as one of the founders of old institutionnalism. It is current to emphazise his philosophical roots : the american pragmatism, at least in his masterpiece of 1934. On the other hand, it is less frequent to point out the important role that the langage, and a fortiori economics' langage, has in his understanding of institutional evolution. Our aim will be to spotlight this point : for Commons, we can do things with words, on the way of performativist linguistic, when we use words, we influence institutional evolution.

Stabilization of soil hydraulic properties under a long term no-till system

The area under the no-tillage system (NT) has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean) on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam) from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM) model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, &#949;ma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC) for these soils, but not the hydraulic conductivity (K) vs tension (h) curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.

Public-domain software for root image analysis

In the search for high efficiency in root studies, computational systems have been developed to analyze digital images. ImageJ and Safira are public-domain systems that may be used for image analysis of washed roots. However, differences in root properties measured using ImageJ and Safira are supposed. This study compared values of root length and surface area obtained with public-domain systems with values obtained by a reference method. Root samples were collected in a banana plantation in an area of a shallower Typic Carbonatic Haplic Cambisol (CXk), and an area of a deeper Typic Haplic Ta Eutrophic Cambisol (CXve), at six depths in five replications. Root images were digitized and the systems ImageJ and Safira used to determine root length and surface area. The line-intersect method modified by Tennant was used as reference; values of root length and surface area measured with the different systems were analyzed by Pearson's correlation coefficient and compared by the confidence interval and t-test. Both systems ImageJ and Safira had positive correlation coefficients with the reference method for root length and surface area data in CXk and CXve. The correlation coefficient ranged from 0.54 to 0.80, with lowest value observed for ImageJ in the measurement of surface area of roots sampled in CXve. The IC (95 %) revealed that root length measurements with Safira did not differ from that with the reference method in CXk (-77.3 to 244.0 mm). Regarding surface area measurements, Safira did not differ from the reference method for samples collected in CXk (-530.6 to 565.8 mm��) as well as in CXve (-4231 to 612.1 mm��). However, measurements with ImageJ were different from those obtained by the reference method, underestimating length and surface area in samples collected in CXk and CXve. Both ImageJ and Safira allow an identification of increases or decreases in root length and surface area. However, Safira results for root length and surface area are closer to the results obtained with the reference method.