Assessing biophysical variable parameters of bean crop with hyperspectral measurements

Recently high spectral resolution sensors have been developed, which allow new and more advanced applications in agriculture. Motivated by the increasing importance of hyperspectral remote sensing data, the need for research is important to define optimal wavebands to estimate biophysical parameters of crop. The use of narrow band vegetation indices (VI) derived from hyperspectral measurements acquired by a field spectrometer was evaluated to estimate bean (Phaseolus vulgaris L.) grain yield, plant height and leaf area index (LAI). Field canopy reflectance measurements were acquired at six bean growth stages over 48 plots with four water levels (179.5; 256.5; 357.5 and 406.2 mm) and tree nitrogen rates (0; 80 and 160 kg ha-1) and four replicates. The following VI was analyzed: OSNBR (optimum simple narrow-band reflectivity); NB_NDVI (narrow-band normalized difference vegetation index) and NDVI (normalized difference index). The vegetation indices investigated (OSNBR, NB_NDVI and NDVI) were efficient to estimate LAI, plant height and grain yield. During all crop development, the best correlations between biophysical variables and spectral variables were observed on V4 (the third trifoliolate leaves were unfolded in 50 % of plants) and R6 (plants developed first flowers in 50 % of plants) stages, according to the variable analyzed.

Phosphite as phosphorus source to grain yield of common bean plants grown in soils under low or adequate phosphate availability

The effects of foliar and soil applied phosphite on grain yield in common bean (Phaseolus vulgaris L.) grown in a weathered soil under low and adequate phosphate availability were evaluated. In the first experiment, treatments were composed of a 2 x 7 + 2 factorial scheme, with 2 soil P levels supplied as phosphate (40 e 200 mg P dm-3 soil), 7 soil P levels supplied as phosphite (0-100 mg P dm-3 soil), and 2 additional treatments (without P supply in soil, and all P supplied as phosphite). In the second experiment, treatments were composed of a 2 x 3 x 2 factorial scheme, with 2 soil phosphate levels (40 e 200 mg P dm-3 soil), combined with 3 nutrient sources applied via foliar sprays (potassium phosphite, potassium phosphate, and potassium chloride as a control), and 2 foliar application numbers (single and two application). Additional treatments showed that phosphite is not P source for common bean nutrition. Phosphite supply in soil increased the P content in shoot (at full physiological maturity stage) and grains, but at the same time considerably decreased grain yield, regardless of the soil phosphate availability. Foliar sprays of phosphite decreased grain yield in plants grown under low soil phosphate availability, but no effect was observed in plants grown under adequate soil phosphate availability. In general, foliar sprays of phosphate did not satisfactorily improve grain yield of the common bean plants grown under low soil phosphate availability.

Will Whole-Tree Harvest of Jack Pine (Pinus banksiana) deplete soil nutrients in low-productivity sand soils?

In 2009 and 2010 a study was conducted on the Hiawatha National Forest (HNF) to determine if whole-tree harvest (WTH) of jack pine would deplete the soil nutrients in the very coarse-textured Rubicon soil. WTH is restricted on Rubicon sand in order to preserve the soil fertility, but the increasing construction of biomass-fueled power plants is expected to increase the demand for forest biomass. The specific objectives of this study were to estimate biomass and nutrient content of above- and below-ground tree components in mature jack pine (Pinus banksiana) stands growing on a coarse-textured, low-productivity soil, determine pools of total C and N and exchangeable soil cations in Rubicon sand, and to compare the possible impacts of conventional stem-only harvest (CH) and WTH on soil nutrient pools and the implications for productivity of subsequent rotations. Four even-aged jack pine stands on Rubicon soil were studied. Allometric equations were used to estimate above-ground biomass and nutrients, and soil samples from each stand were taken for physical and chemical analysis. Results indicate that WTH will result in cation deficits in all stands, with exceptionally large Ca deficits occurring in two stands. Where a deficit does not occur, the cation surplus is small and, chemical weathering and atmospheric deposition is not anticipated to replace the removed cations. CH will result in a surplus of cations, and will likely not result in productivity declines during the first rotation. However even under CH, the surplus is small, and chemical weathering and atmospheric deposition will not supply enough cations for the second rotation.

Peptide and amino acid transporters are differentially regulated during seed development and germination in faba bean

Two peptide transporter (PTR) homologs have been isolated from developing seeds of faba bear, (Vicia faba). VfPTR1 was shown to be a functional peptide transporter through complementation of a yeast mutant. Expression patterns of VfPTR1 and VfPTR2 as well as of the amino acid permease VfAAP1 (Miranda et al., 2001) were compared throughout seed development and germination. In developing seeds, the highest levels of VfPTR1 transcripts were reached during midcotyledon development, whereas VfAAP1 transcripts were most abundant during early cotyledon development, before the appearance of storage protein gene transcripts, and were detectable until late cotyledon development. During early germination, VfPTR1 mRNA appeared first in cotyledons and later, during seedling growth, also in axes and roots. Expression of VfPTR2 and VfAAP1 was delayed compared with VfPTR1, and was restricted to the nascent organs of the seedlings. Localization of VfPTR1 transcripts showed that this FTR is temporally and spatially regulated during cotyledon development. In germinating seeds, VfPTR1 mRNA was localized in root hairs and root epidermal cells, suggesting a role in nutrient uptake from the soil. In seedling roots, VfPTR1 was repressed by a dipeptide and by an amino acid, whereas nitrate was without influence.

Jack-of-all-trades effects drive biodiversity–ecosystem multifunctionality relationships in European forests

There is considerable evidence that biodiversity promotes multiple ecosystem functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. However, the mechanisms underlying this relationship are poorly understood, especially in natural ecosystems. We develop a novel approach to partition biodiversity effects on multifunctionality into three mechanisms and apply this to European forest data. We show that throughout Europe, tree diversity is positively related with multifunctionality when moderate levels of functioning are required, but negatively when very high function levels are desired. For two well-known mechanisms, ‘complementarity’ and ‘selection’, we detect only minor effects on multifunctionality. Instead a third, so far overlooked mechanism, the ‘jack-of-all-trades’ effect, caused by the averaging of individual species effects on function, drives observed patterns. Simulations demonstrate that jack-of-all-trades effects occur whenever species effects on different functions are not perfectly correlated, meaning they may contribute to diversity–multifunctionality relationships in many of the world’s ecosystems.

Jack London: Die Herrin des großen Hauses [Rezension]

J-e.

Revision der im Exsiccat "Kryptogamen Badens von Jack, Leiner und Stitzenberger" enthaltenen Chytridiaceen, Peronosporeen, Ustilagineen und Uredineen

Von G. Lagerheim

Dr. Joseph Bernhard Jack

Anonym

Henry Neville als Jack Dudley, Rollenbild, Kniestück

Signatur des Originals: S 36/F09412

Puntos de vista acerca de la revolución mexicana en John Reed y Jack London

En el presente trabajo me centraré en el análisis comparado de "El mexicano" (1911) de Jack London con México insurgente (1914) y tres cuentos incluidos en Hija de la revolución y otros cuentos: "Mac-American" (1914), "Cuadros de México" (1914) y ?Endimión o en la frontera? (1916) de John Reed. El objetivo que me propongo es el de establecer una correlación entre dos autores que abordan en sus escritos el tema de la revolución mexicana a partir de un análisis comparado de las obras antes mencionadas. Las primeras hipótesis que construí parten de la base común de ofrecernos una visión particular del fenómeno político, social y económico que marcó a México a principios del siglo XX: la revolución mexicana. Tomando como eje de comparación esta semejanza pude ir encontrando, a lo largo del análisis, puntos de divergencia en el modo en que estos dos escritores abordaron este mismo suceso. Por un lado se sitúa London, quien construye en "El mexicano" una representación simplista tanto de las características del revolucionario y de las motivaciones que lo llevan a decidirse por la lucha armada, como del régimen al que éste se opone. Frente a esta representación populista de la revolución mexicana, Reed pone en primer plano, tanto en México insurgente como en sus cuentos, lo complejo de ese mismo hecho ya sea por la confusión de los revolucionarios en torno al trasfondo ideológico que la revolución conllevó o por las diferentes motivaciones que los impulsaron a participar en la misma. Esta tesis inicial de la complejidad de la representación en Reed se sustenta, en el plano formal, por lo que podríamos denominar "técnica del montaje mural", en relación con el movimiento artístico denominado "muralismo" que se desarrolló en México luego de la revolución

Puntos de vista acerca de la revolución mexicana en John Reed y Jack London

En el presente trabajo me centraré en el análisis comparado de "El mexicano" (1911) de Jack London con México insurgente (1914) y tres cuentos incluidos en Hija de la revolución y otros cuentos: "Mac-American" (1914), "Cuadros de México" (1914) y ?Endimión o en la frontera? (1916) de John Reed. El objetivo que me propongo es el de establecer una correlación entre dos autores que abordan en sus escritos el tema de la revolución mexicana a partir de un análisis comparado de las obras antes mencionadas. Las primeras hipótesis que construí parten de la base común de ofrecernos una visión particular del fenómeno político, social y económico que marcó a México a principios del siglo XX: la revolución mexicana. Tomando como eje de comparación esta semejanza pude ir encontrando, a lo largo del análisis, puntos de divergencia en el modo en que estos dos escritores abordaron este mismo suceso. Por un lado se sitúa London, quien construye en "El mexicano" una representación simplista tanto de las características del revolucionario y de las motivaciones que lo llevan a decidirse por la lucha armada, como del régimen al que éste se opone. Frente a esta representación populista de la revolución mexicana, Reed pone en primer plano, tanto en México insurgente como en sus cuentos, lo complejo de ese mismo hecho ya sea por la confusión de los revolucionarios en torno al trasfondo ideológico que la revolución conllevó o por las diferentes motivaciones que los impulsaron a participar en la misma. Esta tesis inicial de la complejidad de la representación en Reed se sustenta, en el plano formal, por lo que podríamos denominar "técnica del montaje mural", en relación con el movimiento artístico denominado "muralismo" que se desarrolló en México luego de la revolución

Puntos de vista acerca de la revolución mexicana en John Reed y Jack London

En el presente trabajo me centraré en el análisis comparado de "El mexicano" (1911) de Jack London con México insurgente (1914) y tres cuentos incluidos en Hija de la revolución y otros cuentos: "Mac-American" (1914), "Cuadros de México" (1914) y ?Endimión o en la frontera? (1916) de John Reed. El objetivo que me propongo es el de establecer una correlación entre dos autores que abordan en sus escritos el tema de la revolución mexicana a partir de un análisis comparado de las obras antes mencionadas. Las primeras hipótesis que construí parten de la base común de ofrecernos una visión particular del fenómeno político, social y económico que marcó a México a principios del siglo XX: la revolución mexicana. Tomando como eje de comparación esta semejanza pude ir encontrando, a lo largo del análisis, puntos de divergencia en el modo en que estos dos escritores abordaron este mismo suceso. Por un lado se sitúa London, quien construye en "El mexicano" una representación simplista tanto de las características del revolucionario y de las motivaciones que lo llevan a decidirse por la lucha armada, como del régimen al que éste se opone. Frente a esta representación populista de la revolución mexicana, Reed pone en primer plano, tanto en México insurgente como en sus cuentos, lo complejo de ese mismo hecho ya sea por la confusión de los revolucionarios en torno al trasfondo ideológico que la revolución conllevó o por las diferentes motivaciones que los impulsaron a participar en la misma. Esta tesis inicial de la complejidad de la representación en Reed se sustenta, en el plano formal, por lo que podríamos denominar "técnica del montaje mural", en relación con el movimiento artístico denominado "muralismo" que se desarrolló en México luego de la revolución