Silicon attenuates calcium deficiency by increasing ascorbic acid content, growth and quality of cabbage leaves.

Calcium (Ca) deficiency in cabbage plants induces oxidative damage, hampering growth and decreasing quality, however, it is hypothesized that silicon (Si) added to the nutrient solution may alleviate crop losses. Therefore, this study aims at evaluating whether silicon supplied in the nutrient solution reduces, in fact, the calcium deficiency effects on cabbage plants. In a greenhouse, cabbage plants were grown using nutrient solutions with Ca sufficiency and Ca deficiency (5 mM) without and with added silicon (2.5 mM), arranged as a 2 × 2 factorial in randomized blocks, with five replications. At 91 days after transplanting, the plants were harvested for biological evaluations. In the treatment without added Si, Ca deficiency promoted oxidative stress, low antioxidant content, decreased dry matter, and lower quality leaf. On the other hand, added Si attenuated Ca deficiency in cabbage by decreasing cell extravasation while increasing both ascorbic acid content and fresh and dry matter, providing firmer leaves due to diminished leaf water loss after harvesting. We highlighted the agronomic importance of Si added to the nutrient solution, especially in crops at risk of Ca deficiency.

Exploring the role of zinc fertilization methods for agronomic bio-fortification and its impact on phenology, growth and yield characteristics of maize / Explorando o papel dos métodos de fertilização com zinco para bio-fortificação agronômica e seu impacto na fenologia, crescimento e características de rendimento do milho

Zinc (Zn) is a key mineral nutrient for plant and human growth and its deficiency can reduce the plant growth and development, however; agronomic bio-fortification can cure plant and human Zn deficiency. By using different Zn fertilization approaches, this study investigated the role and its impact on phenology, growth and yield of maize during two growing seasons 2015 and 2016. The treatments comprised of: no Zn application (ZnC0), basal application of 10 kg ZnSO4.7H2O ha-1 (ZnB1), basal application of 15 kg ZnSO4.7H2O ha-1 (ZnB2), foliar application of 1% solution of ZnSO4.7H2O ha-1 (ZnF3), foliar application of 1.5% solution of ZnSO4.7H2O ha-1 (ZnF4) applied to two hybrids of maize (YSM-112 and DK-6525). The maize hybrid DK-6525 showed superiority in term of growth and yield than YSM-112. The ZnF4 brings early emergence, tasseling and silking that resulted in early crop maturity. However, ZnB2 improved crop growth rate, grain yield and Zn concentration in maize grain by 44, 11.39 and 33.24%, respectively than ZnC0 (control). Regression model indicated that each 1 g increment in 1000-grain weight improved the grain yield by 0.01 and 0.16 t ha-1 of YSM-112 and DK-6525, respectively. Conclusively, it is concluded that DK-6525 with ZnB2 is suitable for optimal growth and yield of maize and would also be helpful to optimize the yield and Zn concentration of maize.

O zinco (Zn) é um nutriente mineral chave para o crescimento de plantas e humanos, e sua deficiência pode reduzir o crescimento e o desenvolvimento das plantas; bio-fortificação agronômica pode curar a deficiência de Zn humano e vegetal. Utilizando diferentes abordagens de fertilização com Zn, este estudo investigou o papel e seu impacto na fenologia, crescimento e produção de milho durante duas safras 2015 e 2016. Os tratamentos foram compostos por: sem aplicação de Zn (ZnC0), aplicação basal de 10 kg de ZnSO4. 7H2O ha-1 (ZnB1), aplicação basal de 15 kg de ZnSO4.7H2O ha-1 (ZnB2), aplicação foliar de solução a 1% de ZnSO4.7H2O ha-1 (ZnF3), aplicação foliar de solução a 1,5% de ZnSO4.7H2O ha-1 (ZnF4) aplicado a dois híbridos de milho (YSM-112 e DK-6525). O híbrido de milho DK-6525 apresentou superioridade em termos de crescimento e produtividade que o YSM-112. O ZnF4 traz emergência precoce, pendoamento e silagem que resultaram em maturação precoce da cultura. No entanto, o ZnB2 melhorou a taxa de crescimento da cultura, a produtividade de grãos e a concentração de Zn no grão de milho em 44, 11,39 e 33,24%, respectivamente, do que ZnC0 (controle). O modelo de regressão indicou que cada incremento de 1 g no peso de 1000 grãos melhorou o rendimento de grãos em 0,01 e 0,16 t ha-1 de YSM-112 e DK-6525, respectivamente. Conclusivamente, conclui-se que o DK-6525 com ZnB2 é adequado para o crescimento e produção ideais de milho e também seria útil para otimizar o rendimento e a concentração de Zn do milho.

Morphogenic and structural characteristics and chemical composition of grass aruana, submitted to nitrogen fertilization / Características morfogênicas, estruturais e composição química de capim-aruana, submetido à adubação nitrogenada

This study aimed at evaluating the morphogenic and structural characteristics of Panicum maximum Jacq. cv. Aruana, as well as its chemical composition after submitting it to different nitrogen levels. The experiment was performed by adopting a randomized block design which included four treatments (0, 75, 150 and 225 kg ha-1 of N) and three replications, in 100 m2 plots. Twice a week, for the 63 days of regrowth, the morphogenic characteristics were determined and estimated, after which the chemical composition was assessed. The aruana grass revealed a quadratic and positive response to the nitrogen fertilization, and showed a remarkable rise in the elongation rates, leaf appearance and senescence, besides the number of live leaves per tiller and final leaf length. However, the nitrogen fertilization reduced the phyllochron and leaf life in the aruana grass, implying the direct effect of nitrogen on the flow of tissues. A quadratic and positive effect of the nitrogen fertilization was observed for the dry mass production, from 5,840.80 kg ha-1 for plants lacking the nitrogen fertilization to 8,862.55 kg ha-1 for those fertilized with 225 kg ha-1 of N. Thus, while the nitrogen fertilization positively affected both tillering and morphogenesis, the N doses used in this study were insufficient to induce any change in the chemical composition of the aruana grass.

Objetivou-se avaliar as características morfogênicas, estruturais e a composição química do Panicum maximum Jacq. cv. Aruana sob diferentes doses de nitrogênio. O experimento foi instalado em delineamento de blocos casualizados com quatro tratamentos (0, 75, 150 e 225 kg ha-1 de N) e três repetições, em parcelas de 100 m2. As características morfogênicas foram determinadas duas vezes por semana, durante 63 dias de rebrotação, após a qual estimou-se e determinou-se a composição química. Plantas de capim-aruana responderam de maneira quadrática e positiva à adubação nitrogenada com aumento significativo nas taxas de alongamento, aparecimento e senescência de folhas bem como no número de folhas vivas por perfilhos e no comprimento final da lâmina. Por outro lado, a adubação nitrogenada diminui o filocrono e a duração de vida das folhas em capim-aruana, o que indica efeito direto do nitrogênio no fluxo de tecidos. Observou-se efeito quadrático e positivo da adubação nitrogenada para a produção de massa seca, que variaram de 5.840,80 kg ha-1 para plantas sem adubação nitrogenada a 8.862,55 kg ha-1 para a adubação de 225 kg ha-1 de N. A adubação nitrogenada influencia o perfilhamento e a morfogênese, porém, as doses utilizadas de N não foram suficientes para afetar a composição química em plantas de capim-aruana.

Morphogenic and structural characteristics and chemical composition of grass aruana, submitted to nitrogen fertilization / Características morfogênicas, estruturais e composição química de capim-aruana, submetido à adubação nitrogenada

This study aimed at evaluating the morphogenic and structural characteristics of Panicum maximum Jacq. cv. Aruana, as well as its chemical composition after submitting it to different nitrogen levels. The experiment was performed by adopting a randomized block design which included four treatments (0, 75, 150 and 225 kg ha-1 of N) and three replications, in 100 m2 plots. Twice a week, for the 63 days of regrowth, the morphogenic characteristics were determined and estimated, after which the chemical composition was assessed. The aruana grass revealed a quadratic and positive response to the nitrogen fertilization, and showed a remarkable rise in the elongation rates, leaf appearance and senescence, besides the number of live leaves per tiller and final leaf length. However, the nitrogen fertilization reduced the phyllochron and leaf life in the aruana grass, implying the direct effect of nitrogen on the flow of tissues. A quadratic and positive effect of the nitrogen fertilization was observed for the dry mass production, from 5,840.80 kg ha-1 for plants lacking the nitrogen fertilization to 8,862.55 kg ha-1 for those fertilized with 225 kg ha-1 of N. Thus, while the nitrogen fertilization positively affected both tillering and morphogenesis, the N doses used in this study were insufficient to induce any change in the chemical composition of the aruana grass.(AU)

Objetivou-se avaliar as características morfogênicas, estruturais e a composição química do Panicum maximum Jacq. cv. Aruana sob diferentes doses de nitrogênio. O experimento foi instalado em delineamento de blocos casualizados com quatro tratamentos (0, 75, 150 e 225 kg ha-1 de N) e três repetições, em parcelas de 100 m2. As características morfogênicas foram determinadas duas vezes por semana, durante 63 dias de rebrotação, após a qual estimou-se e determinou-se a composição química. Plantas de capim-aruana responderam de maneira quadrática e positiva à adubação nitrogenada com aumento significativo nas taxas de alongamento, aparecimento e senescência de folhas bem como no número de folhas vivas por perfilhos e no comprimento final da lâmina. Por outro lado, a adubação nitrogenada diminui o filocrono e a duração de vida das folhas em capim-aruana, o que indica efeito direto do nitrogênio no fluxo de tecidos. Observou-se efeito quadrático e positivo da adubação nitrogenada para a produção de massa seca, que variaram de 5.840,80 kg ha-1 para plantas sem adubação nitrogenada a 8.862,55 kg ha-1 para a adubação de 225 kg ha-1 de N. A adubação nitrogenada influencia o perfilhamento e a morfogênese, porém, as doses utilizadas de N não foram suficientes para afetar a composição química em plantas de capim-aruana.(AU)

Exploring the role of zinc fertilization methods for agronomic bio-fortification and its impact on phenology, growth and yield characteristics of maize / Explorando o papel dos métodos de fertilização com zinco para bio-fortificação agronômica e seu impacto na fenologia, crescimento e características de rendimento do milho

Zinc (Zn) is a key mineral nutrient for plant and human growth and its deficiency can reduce the plant growth and development, however; agronomic bio-fortification can cure plant and human Zn deficiency. By using different Zn fertilization approaches, this study investigated the role and its impact on phenology, growth and yield of maize during two growing seasons 2015 and 2016. The treatments comprised of: no Zn application (ZnC0), basal application of 10 kg ZnSO4.7H2O ha-1 (ZnB1), basal application of 15 kg ZnSO4.7H2O ha-1 (ZnB2), foliar application of 1% solution of ZnSO4.7H2O ha-1 (ZnF3), foliar application of 1.5% solution of ZnSO4.7H2O ha-1 (ZnF4) applied to two hybrids of maize (YSM-112 and DK-6525). The maize hybrid DK-6525 showed superiority in term of growth and yield than YSM-112. The ZnF4 brings early emergence, tasseling and silking that resulted in early crop maturity. However, ZnB2 improved crop growth rate, grain yield and Zn concentration in maize grain by 44, 11.39 and 33.24%, respectively than ZnC0 (control). Regression model indicated that each 1 g increment in 1000-grain weight improved the grain yield by 0.01 and 0.16 t ha-1 of YSM-112 and DK-6525, respectively. Conclusively, it is concluded that DK-6525 with ZnB2 is suitable for optimal growth and yield of maize and would also be helpful to optimize the yield and Zn concentration of maize.(AU)

O zinco (Zn) é um nutriente mineral chave para o crescimento de plantas e humanos, e sua deficiência pode reduzir o crescimento e o desenvolvimento das plantas; bio-fortificação agronômica pode curar a deficiência de Zn humano e vegetal. Utilizando diferentes abordagens de fertilização com Zn, este estudo investigou o papel e seu impacto na fenologia, crescimento e produção de milho durante duas safras 2015 e 2016. Os tratamentos foram compostos por: sem aplicação de Zn (ZnC0), aplicação basal de 10 kg de ZnSO4. 7H2O ha-1 (ZnB1), aplicação basal de 15 kg de ZnSO4.7H2O ha-1 (ZnB2), aplicação foliar de solução a 1% de ZnSO4.7H2O ha-1 (ZnF3), aplicação foliar de solução a 1,5% de ZnSO4.7H2O ha-1 (ZnF4) aplicado a dois híbridos de milho (YSM-112 e DK-6525). O híbrido de milho DK-6525 apresentou superioridade em termos de crescimento e produtividade que o YSM-112. O ZnF4 traz emergência precoce, pendoamento e silagem que resultaram em maturação precoce da cultura. No entanto, o ZnB2 melhorou a taxa de crescimento da cultura, a produtividade de grãos e a concentração de Zn no grão de milho em 44, 11,39 e 33,24%, respectivamente, do que ZnC0 (controle). O modelo de regressão indicou que cada incremento de 1 g no peso de 1000 grãos melhorou o rendimento de grãos em 0,01 e 0,16 t ha-1 de YSM-112 e DK-6525, respectivamente. Conclusivamente, conclui-se que o DK-6525 com ZnB2 é adequado para o crescimento e produção ideais de milho e também seria útil para otimizar o rendimento e a concentração de Zn do milho.(AU)

Floral induction management in 'Palmer' mango using uniconazole / Manejo da indução floral da mangueira 'Palmer' com uso de uniconazole

The objective of this study was to evaluate the effects of different doses of uniconazole (UCZ) on 'Palmer' mango vegetative and reproductive response and on fruit physical, chemical, and productive characteristics during the off-season in northern Minas Gerais, Brazil. The experiment followed a randomized block design. UCZ was tested at the following doses applied to leaves and expressed in g of UCZ active ingredient (a.i.) per tree: 0.0, 1.0, and 1.0+1.0 (2.0) after 30 days; 1.0+1.0+1.0 (3.0) subdivided into 30-day intervals; and 1.0+1.0+2.0 (4.0) subdivided into 30-day intervals. All of the UCZ treatments reduced branch elongation in the 'Palmer' mango trees, leading to a mean reduction of 81.6% compared to the control. However, the UCZ application of 1.0+1.0+2.0g a.i. per tree subdivided into 30-day intervals was efficient in promoting flowering during the off-season, enabling a 167% mean increase in the number of fruit per tree and a 9.78t ha-1 mean increase in productivity.(AU)

Este trabalho teve como objetivo avaliar a eficiência da aplicação de diferentes doses de uniconazole (UCZ) em mangueira 'Palmer' no comportamento vegetativo, reprodutivo e nas características físicas, químicas e produtivas dos frutos durante o período de entressafra na região Norte de Minas Gerais. O delineamento experimental foi em blocos ao acaso, testando-se as doses 0,0; 1,0; 1,0+1,0 (2,0) após 30 dias; 1,0+1,0+1,0 (3,0) parcelado a cada 30 dias; 1,0+1,0+2,0 (4,0) parcelado a cada 30 dias, em g, do ingrediente ativo (i.a.) de UCZ por planta, aplicado via foliar. Verificou-se que todos os tratamentos com uso de uniconazole reduziram o alongamento dos ramos da mangueira 'Palmer', quando comparada com a testemunha, apresentando uma redução média de 81,6%, no entanto, apenas a aplicação de 1,0+1,0+2,0g i.a. UCZ/planta parcelado a cada 30 dias foi eficiente em promover a floração no período da entressafra, possibilitando um incremento médio de 167% no número de frutos por planta e de 9,78t ha-1 na produtividade.(AU)

Grape yield, and must compounds of 'Cabernet Sauvignon' grapevine in sandy soil with potassium contents increasing / Produção e composição do mosto de viníferas 'Cabernet Sauvignon' cultivadas em solo arenoso com teores crescentes de potássio

Content of exchangeable potassium (K) in t soil may influence on its content in grapevines leaves, grape yield, as well as, in must composition. The study aimed to assess the interference of exchangeable K content in the soil on its leaf content, production and must composition of 'Cabernet Sauvignon' cultivar. In September 2011, in Santana do Livramento (RS) five vineyards with increasing levels of exchangeable K in the soil were selected. In the 2012/13 and 2013/14 harvests, the grape yield, yield components, total K content in the leaves in full bloom and berries veraison were evaluated. Values of total soluble sugar (TSS), pH, total titratable acidity (TTA), total polyphenols and anthocyanins were evaluated in the must. Exchangeable K content increase in soil with sandy surface texture increased its content in leaves collected during full flowering and in berries and must pH; however, it did not affect production of the 'Cabernet Sauvignon'.(AU)

O potássio (K) é um dos macronutrientes exigidos em maior quantidade pela videira, porém o seu incremento no solo pode não aumentar a produção de uva, mas pode modificar a sua composição. O trabalho objetivou avaliar a interferência do teor de K trocável no solo sobre o seu teor na folha, produção e composição do mosto da cv. 'Cabernet Sauvignon'. Em setembro de 2011, em Santana do Livramento (RS), foram selecionados cinco vinhedos com níveis crescentes de K trocável no solo. Nas safras 2012/13 e 2013/14, foi avaliada a produção de uva, os componentes de produção, o teor total de K nas folhas no pleno florescimento e na mudança da cor das bagas. No mosto, foram avaliados os valores de sólidos solúveis totais (SST), pH, a acidez total titulável (ATT) e os totais de polifenóis e antocianinas. O incremento do teor de K trocável no solo aumentou o K total nas folhas no pleno florescimento, nas bagas e a composição do mosto, mas não afetou a produção de uva da cv. 'Cabernet Sauvignon'.(AU)

Detection of salt marsh vegetation stress and recovery after the Deepwater Horizon Oil Spill in Barataria Bay, Gulf of Mexico using AVIRIS data.

The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

Green chemistry in protected horticulture: the use of peroxyacetic acid as a sustainable strategy.

Global reduction of chemical deposition into the environment is necessary. In protected horticulture, different strategies with biodegradable products are used to control pathogens. This review presents the available tools, especially for the management of protected horticultural species, including vegetables and ornamental plants. An analysis of the potential for degradable products that control pathogens and also encourage other productive factors, such as oxygen in the root system, is presented. Biosecurity in fertigation management of protected horticulture is conducted by using peroxyacetic acid mixtures that serve three basic principles: first, the manufacture of these products does not involve polluting processes; second, they have the same function as other chemicals, and third, after use and management there is no toxic residue left in the environment. The sustainability of protected horticulture depends on the development and introduction of technologies for implementation in the field.

Agrobacterium rhizogenes vs auxinic induction for in vitro rhizogenesis of Prosopis chilensis and Nothofagus alpina

The induction and improvement of in vitro rhizogenesis of microshoots of Prosopis chilensis (Mol.) Stuntz and Nothofagus alpina (Poep. et Endl. Oerst.) were compared using Agrobacterium rhizogenes (Ar) versus indole-3-butyric acid (IBA) in the culture media. Microshoots of P. chilensis (1-2 cm length), coming from in vitro grown seedlings, were cultivated in a modified Broadleaved Tree Medium (BTMm) containing half salt concentration of macronutrients and 0.05 mg x L(-1) benzilaminopurine (BAP). After 30 days, microshoots with 2-4 leaves were selected and cultured in BTMm-agar in presence or abscense of Ar and in combination with IBA. For N. alpina, the apical shoots with the first 2 true leaves, from 5 weeks old seedlings, were cultured in the abovementioned medium, but with 0.15 mg x L(-1) of BAP. After 2 months, microshoots with 2-3 leaves were selected and cultured in BTMm-agar, supplemented with 5 mg x L(-1) IBA or in liquid BTMm on perlite and, in the presence or absence of A. rhizogenes (Ar) and in combination with 3 mg x L(-1) IBA. Rooting in P. chilensis reached 100.0% when Ar infection was produced in the presence of IBA, increasing both, the number and dry weight of roots. In N. alpina, 90.0% of rooting efficiency was obtained when Ar infection was produced in liquid culture and in the absence of auxin.

Agrobacterium rhizogenes vs auxinic induction for in vitro rhizogenesis of Prosopis chilensis and Nothofagus alpina

The induction and improvement of in vitro rhizogenesis of microshoots of Prosopis chilensis (Mol.) Stuntz and Nothofagus alpina (Poep. et Endl. Oerst.) were compared using Agrobacterium rhizogenes (Ar) versus indole-3-butyric acid (IBA) in the culture media. Microshoots of P. chilensis (1-2 cm length), coming from in vitro grown seedlings, were cultivated in a modified Broadleaved Tree Medium (BTMm) containing half salt concentration of macronutrients and 0.05 mg x L(-1) benzilaminopurine (BAP). After 30 days, microshoots with 2-4 leaves were selected and cultured in BTMm-agar in presence or abscense of Ar and in combination with IBA. For N. alpina, the apical shoots with the first 2 true leaves, from 5 weeks old seedlings, were cultured in the abovementioned medium, but with 0.15 mg x L(-1) of BAP. After 2 months, microshoots with 2-3 leaves were selected and cultured in BTMm-agar, supplemented with 5 mg x L(-1) IBA or in liquid BTMm on perlite and, in the presence or absence of A. rhizogenes (Ar) and in combination with 3 mg x L(-1) IBA. Rooting in P. chilensis reached 100.0% when Ar infection was produced in the presence of IBA, increasing both, the number and dry weight of roots. In N. alpina, 90.0% of rooting efficiency was obtained when Ar infection was produced in liquid culture and in the absence of auxin. (AU)

Agrobacterium rhizogenes vs auxinic induction for in vitro rhizogenesis of Prosopis chilensis and Nothofagus alpina.

The induction and improvement of in vitro rhizogenesis of microshoots of Prosopis chilensis (Mol.) Stuntz and Nothofagus alpina (Poep. et Endl. Oerst.) were compared using Agrobacterium rhizogenes (Ar) versus indole-3-butyric acid (IBA) in the culture media. Microshoots of P. chilensis (1-2 cm length), coming from in vitro grown seedlings, were cultivated in a modified Broadleaved Tree Medium (BTMm) containing half salt concentration of macronutrients and 0.05 mg x L(-1) benzilaminopurine (BAP). After 30 days, microshoots with 2-4 leaves were selected and cultured in BTMm-agar in presence or abscense of Ar and in combination with IBA. For N. alpina, the apical shoots with the first 2 true leaves, from 5 weeks old seedlings, were cultured in the abovementioned medium, but with 0.15 mg x L(-1) of BAP. After 2 months, microshoots with 2-3 leaves were selected and cultured in BTMm-agar, supplemented with 5 mg x L(-1) IBA or in liquid BTMm on perlite and, in the presence or absence of A. rhizogenes (Ar) and in combination with 3 mg x L(-1) IBA. Rooting in P. chilensis reached 100.0% when Ar infection was produced in the presence of IBA, increasing both, the number and dry weight of roots. In N. alpina, 90.0% of rooting efficiency was obtained when Ar infection was produced in liquid culture and in the absence of auxin.

Vegetative propagation of Cecropia obtusifolia (Cecropiaceae).

Cecropia is a relatively well-known and well-studied genus in the Neotropics. Methods for the successful propagation of C. obtusifolia Bertoloni, 1840 from cuttings and air layering are described, and the results of an experiment to test the effect of two auxins, naphthalene acetic acid (NAA) and indole butyric acid (IBA), on adventitious root production in cuttings are presented. In general, C. obtusifolia cuttings respond well to adventitious root production (58.3% of cuttings survived to root), but air layering was the better method (93% of cuttings survived to root). The concentration of auxins used resulted in an overall significantly lower quality of roots produced compared with cuttings without auxin treatment. Future experiments using Cecropia could benefit from the use of isogenic plants produced by vegetative propagation.

Morphogenesis in short-term and long-term anther derived calli of Oenothera hookeri de vries

Anther culture of O. hookeri on Murashige and Skoog (1962) medium supplemented with 2 mg l-1 2,4-dichlorophenoxyacetic acid and 2 mg-1 1-naphthaleneacetic acid produced callus formation. When subcultured onto medium lacking auxin, the callus regenerated through the organogenic pathway. Non-organogenic and organogenic callus was observed using histological methods after 2, 3 and 24 weeks in culture. Three types of calli were recognized: non-organogenic friable calli, organogenic friable calli with roots and organogenic hard calli with shoots. The microscopical sections showed striking differences in tissue organization among friable and compact calli. Vascular bundles were prominent in compact calli, but were not found in friable calli. Calli sections showed at light microscopy cells at two developmental stages; differentiated highly vacuolated cells and meristematic small isodiametric cells with densely stained cytoplasm. At electron microscopy level abnormal chloroplasts were present in non-organogenic calli, while chloroplasts were well developed in organogenic hard calli. Peroxisomes with paracrystalline protein bodies were abundant in both types of calli.(AU)

Morphogenesis in short-term and long-term anther derived calli of Oenothera hookeri de vries.

Anther culture of O. hookeri on Murashige and Skoog (1962) medium supplemented with 2 mg l-1 2,4-dichlorophenoxyacetic acid and 2 mg-1 1-naphthaleneacetic acid produced callus formation. When subcultured onto medium lacking auxin, the callus regenerated through the organogenic pathway. Non-organogenic and organogenic callus was observed using histological methods after 2, 3 and 24 weeks in culture. Three types of calli were recognized: non-organogenic friable calli, organogenic friable calli with roots and organogenic hard calli with shoots. The microscopical sections showed striking differences in tissue organization among friable and compact calli. Vascular bundles were prominent in compact calli, but were not found in friable calli. Calli sections showed at light microscopy cells at two developmental stages; differentiated highly vacuolated cells and meristematic small isodiametric cells with densely stained cytoplasm. At electron microscopy level abnormal chloroplasts were present in non-organogenic calli, while chloroplasts were well developed in organogenic hard calli. Peroxisomes with paracrystalline protein bodies were abundant in both types of calli.

Germination responses and boron accumulation in germplasm from Chile and the United States grown with boron-enriched water.

Boron (B) is toxic to most plant species when accumulated in high concentrations. Differences in a plant's ability to adapt to high concentrations of B may depend on the origin of the germplasm. Chilean and domestic (U.S.) germplasm, corn (Zea mays L.), carrots (Daucus carotas), tomato (Lycopersicum esculentum L.), and alfalfa (Medicago sativa L.) were evaluated for germination, emergence of cotyledonary leaves, and tissue B accumulation under high-B conditions in both an environmental growth chamber and a greenhouse. Increasing B levels (20-40 mg B liter-1) inhibited the percentage germination for both the Chilean and domestic germplasm. Chilean germplasm exhibited generally a greater percentage of healthy cotyledonary leaves at the 20 mg B liter-1 treatment than the domestic germplasm. Comparing B concentrations between both germplasm grown and irrigated with B-enriched water (10-20 mg B liter-1) under greenhouse conditions, leaves from domestic germplasm contained more B. Moreover, B troxicity symptoms were more severe for the tested plant species from the domestic germplasm. Apparent B tolerance by germplasm of different origin should be further tested under field conditions.

Contribuição ao estudo de Laurus nobilis l. (louro) / Contribution to the study of Laurus nobilis l. (louro)

Realizou-se a caracterização química, macroscópica e microscópica das folhas de Laurus nobilis L. (louro),com a finalidade de contribuir para a sua identificação e controle de qualidade, já que é utilizado pela população como condimento e fitoterápico. Na caracterização química, ralizada segundo as técnicas da Farmacopéia Brasileira,1977 e Instituto Adolfo Lutz, 1976, determinou-se a umidade, resíduo mineral fixo, extratos alcoólico, aquoso,etéreo e seco, nitrogênio total, proteína bruta e fibra bruta....