Roles of glycine betaine and proline in improving plant abiotic stress resistance

Salt tolerance and salinity effects on plants: a review.

Developments in nanotechnology are leading to a rapid proliferation of new materials that are likely to become a source of engineered nanoparticles (ENPs) to the environment, where their possible ecotoxicological impacts remain unknown. The surface properties of ENPs are of essential importance for their aggregation behavior, and thus for their mobility in aquatic and terrestrial systems and for their interactions with algae, plants and, fungi. Interactions of ENPs with natural organic matter have to be considered as well, as those will alter the ENPs aggregation behavior in surface waters or in soils. Cells of plants, algae, and fungi possess cell walls that constitute a primary site for interaction and a barrier for the entrance of ENPs. Mechanisms allowing ENPs to pass through cell walls and membranes are as yet poorly understood. Inside cells, ENPs might directly provoke alterations of membranes and other cell structures and molecules, as well as protective mechanisms. Indirect effects of ENPs depend on their chemical and physical properties and may include physical restraints (clogging effects), solubilization of toxic ENP compounds, or production of reactive oxygen species. Many questions regarding the bioavailability of ENPs, their uptake by algae, plants, and fungi and the toxicity mechanisms remain to be elucidated.

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Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi

Nanoparticulate material delivery to plants

Photosynthesis and activity of superoxide dismutase, peroxidase and glutathione reductase in cotton under salt stress

O crescimento e a eficiencia na conversao da energia solar foram estudados em soja (Glycine max (L.) Merri ll, cv. 'Uberaba'), cultivada em condicoes de campo, sob quatro doses de metribuzin (0, 0,35; 0,70 e 1,05 kg i.a.ha-1). O valor maximo da conversao da energia solar foi de 0,75%, para as plantas cultiva das na maior dose do herbicida. Os valores da conversao da energia solar media durante o ciclo da cultura foram 0,32 ; 0,31 ; 0,32 e 0,33%. em ordem crescente de dose do metribuzin. De modo geral, na fase vegetativa as plantas controle apresentaram valores inferiores em todos os valores de crescimento determinados, superando as tratadas com metribuzin somente na fase reprodutiva, mostrando que no periodo critico de competicao o dano causado pelas plantas daninhas e maior que a possivel fitotoxicida de causada pelo metribuzin.

/pdf/efeito-de-doses-de-metribuzin-no-crescimento-e-na-conversao-57p4ijwkje.pdf

Efeito de doses de metribuzin no crescimento e na conversão da energia solar em plantas de soja (Glycine max (L .) merrill)

Planta from lAN 717, lAN 873, lAN 2903, lAN 3087, lAN 6323 and Fx 3899 rubber tree (Hevea spp.) clones grown in a greenhouse were subjected to cycles of water deficit with the objec- tive of evaluating the elfecta on growth and assimilation partitioning. After 185 days and tive cycles of stress, a reduction in the number of leaves, iii the number of flushes, and in the Iength and diameter of the shoots occurred in the majority of the clones. The lAN 2903 progeny showed an increase in the number of leaves (4,7%) and in the number of flushes (10%). Shoots of the lAN 717 and lAN 3087 progenies were the Ieast affected in their growth. The assimilation partitioning showed a modification in relation to the sinks occurring with the deficit; the prefered sinks were the root In the Fx 3899 and 873 progenies the stem in the lAN 3087 and lAN 6323 progenies and the leaf in the lAN 717 and lAN 2903 progenies. The ratio of the aerial part te the root system was greater in the lAN 2903 progeny and smaller in the Fx 3899 progeny. Ijnder water stress no significam changes occurred in the specific leaf area production values for leaf area and in the leaf area ratio, but the net assimilation value and the accumulation and production of dry matter decreased differentially when submitted to water deficit. The dona Ieast affected by the stress was lAN 3087. The greatest reductions on studied parameters occurred in Fx 3899. The resulta observed in each dono were discussed in relation to each parameter studied.

Resistcncia á seca em seringueira.

Foi estudado o efeito do sombreamento artificial sobre a resistencia estomatica e as condicoes microclimaticas na cultura da soja ( Glycine max (L.) Merrill). As telas plasticas usadas para regular o nivel de radiacao solar (30%, 50%, 70% e 100%) alteraram a qualidade da luz incidente sobre as plantas. No entanto, a temperatura e a umidade relativa do ar nao foram modificadas, embora a temperatura da copa das plantas tenha decrescido com o sombreamento. As plantas sombreadas apresentaram maiores valores de resistencia estomatica que as plantas expostas a plena radiacao solar.

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Influência do sombreamento artificial nas condições microclimáticas na cultura da soja

Contents of chlorophyll and crude protein in soyabean (Glycine max (L.) Merrill) treated with imazaquin.

Stomatal sensitivity to abscisic acid (ABA) can be modified by variations in the xylem sap traits such as pH, Ca2+, NO3- and PO43- concentrations. In order to verify this hypothesis, plants of Licopersicon esculentum L. cv. Santa Clara were submitted to sudden and slow onset of water stress by PEG 6000 addition to the nutritive solution. The stomatal sensitivity to ABA was estimated by changes in the transpiration/xylematic ABA ratio. To evaluate the inhibitory effect of Ca2+, NO3- and PO43- at different concentrations, detached leaves were submerged in artificial sap containing exogenous ABA. In intact plants, under sudden stress treatment, the ion concentration increment gradually raised the stomatal sensitivity to xylem ABA. Under slow stress treatment the stomatal response to ABA was not modified by Ca2+. A dose of 2.5 µM exogenous ABA was needed to induce a drop in the transpiration rate of detached leaves. The presence of Ca2+ in the transpiration flux stimulated the ABA inhibitory effect on transpiration rate.The stomatal closure response to ABA was intensified when Ca2+ and NO3- were added to the artificial sap.

/pdf/sensibilidade-estomatica-ao-aba-em-funcao-do-ph-e-de-niveis-2bvtm674ti.pdf

Marco Antonio Oliva

Papers

Efeito de doses de metribuzin no crescimento e na conversão da energia solar em plantas de soja (Glycine max (L .) merrill)

Resistcncia á seca em seringueira.

Influência do sombreamento artificial nas condições microclimáticas na cultura da soja

Contents of chlorophyll and crude protein in soyabean (Glycine max (L.) Merrill) treated with imazaquin.

Sensibilidade estomática ao ABA em função do pH e de níveis de Ca2+, NO3- e PO4(3-) na seiva do xilema